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Barry, we would love to know what program your friend has that will program the BCM, Thanks, Mike

Not sure if this is what your talking about but found this on the internet....talked with a dealer and if I replace the BCM they have to re-program it. I think this tells how you can do it yourself.

http://www.fullsizechevy.com/forum/general-discussion/performance/port-injection-96-obd-ii/164702-gm-computer-relearn-procedure-including-crankshaft-relearn.html

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When you disconnect the BCM, does it reset the trip odometer?

Not sure...it was already to zero when I unplugged the BCM..

Do me a favor, run up some mileage on the trip odometer.

Park the car, and quickly before the 19 min period shuts it off, disconnect the BCM from power and see if it erases the trip mileage. That will be something good to know

I will do that and let you know...

Okay..I unhooked the BCM and it zeroed out the trip meter, avg mpg, avg mph, gallons used, avg speed etc....the BCM definately controls these digital meters.

I am convinced the problem is in the BCM. I talked with the dealer and they have to re-progam the new or used BCM......I am wondering if I get a used BCM with the same part number as the one I have....only have to re-program the theft security part with the key for the car.

Any thoughts....$431.32 for a new BCM versus $100.00 or less for used one....

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Glad to see that you guys are still hot on the trail of this problem. My trip info resets at between 19 and 20 minutes.

I am still experiencing the problem with the RKE turning the radio on then off before it opens the doors, as described in earlier posts. This problem has become more intermittent now that the weather is colder. Sometimes it only takes one click and the radio cycles. Sometimes the doors unlock on one click and the radio does not cycle on and off. I suspect the problem is related to outside temperature.

I am not sure if this problem and the reset problem have a common cause. Now that the symptoms of one problem have changed I will time the reset problem again and see if it is still 19 to 20 minutes. What does the RKE the radio and the trip info have in common? Sounds like a tribond trivia question.

I appreciate your tenacity on this problem. Wish I could be more help.

I think your problems relate to the BCM....it controls your remotes also...

Okay..I unhooked the BCM and it zeroed out the trip meter, avg mpg, avg mph, gallons used, avg speed etc....the BCM definately controls these digital meters.

I am convinced the problem is in the BCM. I talked with the dealer and they have to re-progam the new or used BCM......I am wondering if I get a used BCM with the same part number as the one I have....only have to re-program the theft security part with the key for the car.

Any thoughts....$431.32 for a new BCM versus $100.00 or less for used one....

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Now what I want you to do is to check the power feeds to the BCM, after 19 minutes, see if there is an interruption in power to it...., I would put a meter on the power lead and watch or when it has reset, see if you have power, if you do, I'd suspect BCM. Check grounds also

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Now what I want you to do is to check the power feeds to the BCM, after 19 minutes, see if there is an interruption in power to it...., I would put a meter on the power lead and watch or when it has reset, see if you have power, if you do, I'd suspect BCM. Check grounds also

Hmmmm....getting above my skill level on this one...I know you are right...it would eliminate everything but the BCM.

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Yep, don't worry about the grounds right now, just check for power, if power remains constant after the 19 min shut down, I would look to a new/used BCM

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Yep, don't worry about the grounds right now, just check for power, if power remains constant after the 19 min shut down, I would look to a new/used BCM

Not sure how to check the power....I don't have a meter...do have a 12volt tester (with the bulb that lights up when there is power) What wire would be the power coming into the BCM?

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OK, there is a 10 amp fuse "comfort fuse" in the trunk compartment, it is HOT at all times to terminal B3, check that fuse for corrosion and loose connections.

The power runs from the fuse to the BCM via an ORANGE wire (at least on the 96) on what appears to be terminal B3

Do you have any PZ codes?

It is very interesting to note that the BCM is tied in to the Retained Accessory Power via PZM fuse (10 amp) at C2 and there is a controlled power relay. Modules under the Controlled Power Relay are supplied power through the Controlled Power Relay to the High Power Control...hmmm. The High Power Control is grounded whenever the PZM or BCM is awake and for 15 minutes after the ignition switch is turned to the LOCK position.

My guess is this, you are NOT going to find power to terminal C2 for some reason. There is a junction at S404 that branches off to the orange wire going to B3 and to the controlled power relay. I need to scan some pictures for you and this will make more sense.

I would advise that you buy an inexpensive digital voltmeter, home depot or lowes, but stay away from radio shack junk spend up to $40. But, check for power on B3.

Stay patient, I need to run some scans for you and read this section of my manual. I think we can figure this out now and it may not be the BCM.

Check for PZ codes. Do not test without me coming back to you. There is more than one orange wire. If you pull the plug on the BCM see if it is marked, you are looking for terminal B3. Looking at the plug with the flat part of the plug DOWN, the bottom row is B, and it is numbered 1 to 12 from left to right. Ill post a scan of the plug and do some more research.

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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OK, there is a 10 amp fuse "comfort fuse" in the trunk compartment, it is HOT at all times to terminal B3, check that fuse for corrosion and loose connections.

The power runs from the fuse to the BCM via an ORANGE wire (at least on the 96) on what appears to be terminal B3

Do you have any PZ codes?

It is very interesting to note that the BCM is tied in to the Retained Accessory Power via PZM fuse (10 amp) at C2 and there is a controlled power relay. Modules under the Controlled Power Relay are supplied power through the Controlled Power Relay to the High Power Control...hmmm. The High Power Control is grounded whenever the PZM or BCM is awake and for 15 minutes after the ignition switch is turned to the LOCK position.

My guess is this, you are NOT going to find power to terminal C2 for some reason. There is a junction at S404 that branches off to the orange wire going to B3 and to the controlled power relay. I need to scan some pictures for you and this will make more sense.

I would advise that you buy an inexpensive digital voltmeter, home depot or lowes, but stay away from radio shack junk spend up to $40. But, check for power on B3.

Stay patient, I need to run some scans for you and read this section of my manual. I think we can figure this out now and it may not be the BCM.

Check for PZ codes. Do not test without me coming back to you. There is more than one orange wire. If you pull the plug on the BCM see if it is marked, you are looking for terminal B3. Looking at the plug with the flat part of the plug DOWN, the bottom row is B, and it is numbered 1 to 12 from left to right. Ill post a scan of the plug and do some more research.

I will wait till you get the pics out...closest Lowes or Home Depot is 125 miles one way....Billings MT....long highways here in Wyoming.

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Wow, God's country, nice!

I need to go out, Ill scan when I can. I think you can use that test light to check for power, by backfeeding the plug, I need to get you a photo of the plug

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Wow, God's country, nice!

I need to go out, Ill scan when I can. I think you can use that test light to check for power, by backfeeding the plug, I need to get you a photo of the plug

Sounds good....Thanks

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OK this should help you diagnose. You should be able to check the power from the back. BE CAREFUL, that you are checking the correct circuit. Remember that when the connector is connected you are looking at a mirror image (probably obvious, but I wanted to say that anyway). I would take the plug out and compare it to the photo I posted above, follow the pin to the color of the wire that you are testing. I noted the colors that you are looking at above.

post-2998-132007165999_thumb.gif

post-2998-132007166679_thumb.jpg

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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My description above was wrong, I dont know how I made that mistake. B1 (Orange Wire) is hot at all times out of S404. That is where I think your problem is, you want to check for power on B1 (key off). IF there was no power on B1 either from a bad fuse or corrosion, your BCM would energize when the key was turned on, and shut down 15 to 20 min later. Not sure if that would set a code, but it seems logical given your symptoms.

By the way, if you look at BCM Scan 2 of 2 below, B3 is fed via IGN power, meaning it is fed when the key is on. (Maybe my 96 manual shows something different, these scans are from a 98 manual).

Look over these scans attached below. Make sure you check the fuses that feed the BCM also both for a good fuse (ohm meter continuity check) and for corrosion that can cause a bad connection. You should purchase a digital volt/ohm meter, you could check the ground on A12. Good Luck, hope this helps

post-2998-132007232585_thumb.gif

post-2998-132007233344_thumb.gif

post-2998-132007234091_thumb.gif

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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My description above was wrong, I dont know how I made that mistake. B1 (Orange Wire) is hot at all times out of S404. That is where I think your problem is, you want to check for power on B1 (key off). IF there was no power on B1 either from a bad fuse or corrosion, your BCM would energize when the key was turned on, and shut down 15 to 20 min later. Not sure if that would set a code, but it seems logical given your symptoms.

By the way, if you look at BCM Scan 2 of 2 below, B3 is fed via IGN power, meaning it is fed when the key is on. (Maybe my 96 manual shows something different, these scans are from a 98 manual).

Look over these scans attached below. Make sure you check the fuses that feed the BCM also both for a good fuse (ohm meter continuity check) and for corrosion that can cause a bad connection. You should purchase a digital volt/ohm meter, you could check the ground on A12. Good Luck, hope this helps

Thanks...I won't get to it till tomorrow but will let you know what I find.

Thanks again for your help on this.

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My description above was wrong, I dont know how I made that mistake. B1 (Orange Wire) is hot at all times out of S404. That is where I think your problem is, you want to check for power on B1 (key off). IF there was no power on B1 either from a bad fuse or corrosion, your BCM would energize when the key was turned on, and shut down 15 to 20 min later. Not sure if that would set a code, but it seems logical given your symptoms.

By the way, if you look at BCM Scan 2 of 2 below, B3 is fed via IGN power, meaning it is fed when the key is on. (Maybe my 96 manual shows something different, these scans are from a 98 manual).

Look over these scans attached below. Make sure you check the fuses that feed the BCM also both for a good fuse (ohm meter continuity check) and for corrosion that can cause a bad connection. You should purchase a digital volt/ohm meter, you could check the ground on A12. Good Luck, hope this helps

Thanks...I won't get to it till tomorrow but will let you know what I find.

Thanks again for your help on this.

I checked the codes today....IPC 1552 history and the battery hasn't been disconnected since codes cleared. The other code was PCM 0463 Current. What do these mean??

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Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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It would be nice if you got DTC's B1972 or B1973, no huh?

DTC P0463 Fuel Level Sensor Circuit High Voltage

Circuit Description

The PCM requires an accurate indictation of fuel level for EVAP system diagnosis. The fuel level in the fuel tank changes the rate of vacuum decay for the EVAP system leak DTCs.

The Fuel Level Sensor changes resistance based on fuel level. The Fuel Level Sensor has a signal circuit and a ground circuit. The PZM (body control module) applies a voltage (about 12 volts) on the signal circuit to the sensor. The PZM monitors changes in this voltage caused by changes in the resistance of the sensor to determine fuel level.

When the fuel tank is full, the sensor resistance is high, and the PZMs signal voltage is only pulled down a small amount through the sensor to ground. Therefore, the PZM will sense a high signal voltage (fuel tank full). When the fuel tank is empty, the sensor resistance is low, and the signal voltage is pulled down a greater amount. This causes the PZM to sense a low signal voltage (fuel tank empty).

The PZM uses inputs from the Fuel Level Sensor to calculate the fuel level in the fuel tank. This information is then sent to the PCM through Serial Data.

When the PCM (through serial data) senses a signal voltage higher than the normal operating range of the sensor, this DTC sets.

Conditions for Running the DTC

  • DTC P0601 is not set.
  • Vehicle speed is more than 5 km/h.

Conditions for Setting the DTC

The fuel level sensor voltage goes above normal operating range for a specific length of time.

Action Taken When the DTC Sets

The PCM uses a fuel remaining value of 40% for the EVAP system diagnostic tests.

  • The Malfunction Indicator Lamp (MIL) will not illuminate.
  • No message will be displayed.

Conditions for Clearing the MIL/DTC

  • A History DTC will clear after forty consecutive warm-up cycles with no failures of any non-emission related diagnostic test.
  • A Last Test Failed (current) DTC will clear when the diagnostic runs and does not fail.
  • Use a scan tool to clear DTCs.
  • Interrupting PCM battery voltage may or may not clear DTCs. This practice is not recommended. Refer to Clearing Diagnostic Trouble Codes in PCM Description and Operation.

Diagnostic Aids

Important

Fuel level is used to determine EVAP system diagnosis. Always diagnose the fuel level sensor before any other EVAP system components or DTCs.

Refer to Fuel Level Sensor Replacement for fuel level sensor diagnosis. Check for IPC or PZM DTCs.

Do not use the fuel gauge as an indication of a shorted or open circuit as the IPC may always default to EMPTY or FULL depending upon vehicle model

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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It would be nice if you got DTC's B1972 or B1973, no huh?

DTC P0463 Fuel Level Sensor Circuit High Voltage

Circuit Description

The PCM requires an accurate indictation of fuel level for EVAP system diagnosis. The fuel level in the fuel tank changes the rate of vacuum decay for the EVAP system leak DTCs.

The Fuel Level Sensor changes resistance based on fuel level. The Fuel Level Sensor has a signal circuit and a ground circuit. The PZM (body control module) applies a voltage (about 12 volts) on the signal circuit to the sensor. The PZM monitors changes in this voltage caused by changes in the resistance of the sensor to determine fuel level.

When the fuel tank is full, the sensor resistance is high, and the PZMs signal voltage is only pulled down a small amount through the sensor to ground. Therefore, the PZM will sense a high signal voltage (fuel tank full). When the fuel tank is empty, the sensor resistance is low, and the signal voltage is pulled down a greater amount. This causes the PZM to sense a low signal voltage (fuel tank empty).

The PZM uses inputs from the Fuel Level Sensor to calculate the fuel level in the fuel tank. This information is then sent to the PCM through Serial Data.

When the PCM (through serial data) senses a signal voltage higher than the normal operating range of the sensor, this DTC sets.

Conditions for Running the DTC

  • DTC P0601 is not set.
  • Vehicle speed is more than 5 km/h.

Conditions for Setting the DTC

The fuel level sensor voltage goes above normal operating range for a specific length of time.

Action Taken When the DTC Sets

The PCM uses a fuel remaining value of 40% for the EVAP system diagnostic tests.

  • The Malfunction Indicator Lamp (MIL) will not illuminate.
  • No message will be displayed.

Conditions for Clearing the MIL/DTC

  • A History DTC will clear after forty consecutive warm-up cycles with no failures of any non-emission related diagnostic test.
  • A Last Test Failed (current) DTC will clear when the diagnostic runs and does not fail.
  • Use a scan tool to clear DTCs.
  • Interrupting PCM battery voltage may or may not clear DTCs. This practice is not recommended. Refer to Clearing Diagnostic Trouble Codes in PCM Description and Operation.

Diagnostic Aids

Important

Fuel level is used to determine EVAP system diagnosis. Always diagnose the fuel level sensor before any other EVAP system components or DTCs.

Refer to Fuel Level Sensor Replacement for fuel level sensor diagnosis. Check for IPC or PZM DTCs.

Do not use the fuel gauge as an indication of a shorted or open circuit as the IPC may always default to EMPTY or FULL depending upon vehicle model

Interesting on the IPC B1522 I will check the ground and power tomorrow and see what I find....very helpful....I was low on gas must have set the other code.

Thanks again..

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It would be nice if you got DTC's B1972 or B1973, no huh?

DTC P0463 Fuel Level Sensor Circuit High Voltage

Circuit Description

The PCM requires an accurate indictation of fuel level for EVAP system diagnosis. The fuel level in the fuel tank changes the rate of vacuum decay for the EVAP system leak DTCs.

The Fuel Level Sensor changes resistance based on fuel level. The Fuel Level Sensor has a signal circuit and a ground circuit. The PZM (body control module) applies a voltage (about 12 volts) on the signal circuit to the sensor. The PZM monitors changes in this voltage caused by changes in the resistance of the sensor to determine fuel level.

When the fuel tank is full, the sensor resistance is high, and the PZMs signal voltage is only pulled down a small amount through the sensor to ground. Therefore, the PZM will sense a high signal voltage (fuel tank full). When the fuel tank is empty, the sensor resistance is low, and the signal voltage is pulled down a greater amount. This causes the PZM to sense a low signal voltage (fuel tank empty).

The PZM uses inputs from the Fuel Level Sensor to calculate the fuel level in the fuel tank. This information is then sent to the PCM through Serial Data.

When the PCM (through serial data) senses a signal voltage higher than the normal operating range of the sensor, this DTC sets.

Conditions for Running the DTC

  • DTC P0601 is not set.
  • Vehicle speed is more than 5 km/h.

Conditions for Setting the DTC

The fuel level sensor voltage goes above normal operating range for a specific length of time.

Action Taken When the DTC Sets

The PCM uses a fuel remaining value of 40% for the EVAP system diagnostic tests.

  • The Malfunction Indicator Lamp (MIL) will not illuminate.
  • No message will be displayed.

Conditions for Clearing the MIL/DTC

  • A History DTC will clear after forty consecutive warm-up cycles with no failures of any non-emission related diagnostic test.
  • A Last Test Failed (current) DTC will clear when the diagnostic runs and does not fail.
  • Use a scan tool to clear DTCs.
  • Interrupting PCM battery voltage may or may not clear DTCs. This practice is not recommended. Refer to Clearing Diagnostic Trouble Codes in PCM Description and Operation.

Diagnostic Aids

Important

Fuel level is used to determine EVAP system diagnosis. Always diagnose the fuel level sensor before any other EVAP system components or DTCs.

Refer to Fuel Level Sensor Replacement for fuel level sensor diagnosis. Check for IPC or PZM DTCs.

Do not use the fuel gauge as an indication of a shorted or open circuit as the IPC may always default to EMPTY or FULL depending upon vehicle model

Interesting on the IPC B1522 I will check the ground and power tomorrow and see what I find....very helpful....I was low on gas must have set the other code.

Thanks again..

UPDATE:

I checked for power and it has power on B1 after the key is turned off for over 20 minutes and there was power...checked the ground on A12 it is good.

I have a BCM coming with the same number as the one in the car. I was told it should hook right up and not need re-programming other than for the key itself. I will put that on and if it doesn't work then I would guess it is the IPC needs replaced.

Your thoughts please on the direction I am going...

Thanks again.

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UPDATE:

I checked for power and it has power on B1 after the key is turned off for over 20 minutes and there was power...checked the ground on A12 it is good.

I have a BCM coming with the same number as the one in the car. I was told it should hook right up and not need re-programming other than for the key itself. I will put that on and if it doesn't work then I would guess it is the IPC needs replaced.

Your thoughts please on the direction I am going...

Thanks again.

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Sounds good, I think you are proceding correct, I would have though you would not have had power on B1, let us know what happens, how much was the BCM?

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Sounds good, I think you are proceding correct, I would have though you would not have had power on B1, let us know what happens, how much was the BCM?

The BCM was $45.00 on Ebay....should have it tomorrow. If that doesn't work then IPC off Ebay....I think if same year and model car should be plug and play....no re-programming..I hope..do you know? I guess the mileage would be different don't know if the dealer could change it?

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I have never done it so I cant help you, maybe someone will chime in

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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I have never done it so I cant help you, maybe someone will chime in

I relly appreciate your help on this...I will let you know the end result and hopefully help.. bpage....I kinda stole his thread....

Thanks again.

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