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Defroster stuck


drew_826

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When i first start the car i can hear a knocking sound under the dash. Its like the gears are stripped. I can't swap from defrost to heat. I was wondering if I needed to change the gears out or if it is possible. Any information would be appreciated. Thanks Drew

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You might be hearing one or more of the HVAC door actuators trying to move.

Display the trouble codes to help you target the correct actuator; there are six actuators under there if my memory is correct.

Here is how to display trouble codes; you will be most interested in B codes

http://www.caddyinfo.com/readingcodes.html

Jim

Drive your car.

Use your cell phone.

CHOOSE ONE !

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Alright i checked the codes this morning. B0249, B0429, B1004 history

I had a few more codes pop up where can i find out what the codes are. or can yall tell me?

Again Thanks for the help. Drew

B0249 - Heater/Defrost/AC Door Range Error

B0429 - Temperature Control #3 Rear Circuit Range/Performance

B1004 - Keep Alive Memory (KAM)

B1004 you can ignore. B0429 is as common as dirt and only has marginal impact on the air temperature blowing toward the rear seat area.

Which leaves B0249. The actuator could be failed/failing, or the door could be sticking. Since you are unable to do any good with the "mode" switch, something has to be repaired. I will be able to help with location and access information later tonight after I help the Cowboys go 13 and 1.

Jim

Drive your car.

Use your cell phone.

CHOOSE ONE !

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You might want to rethink this being a DIY job!! The Service Manual says the entire Instrument Panel Assembly has to be removed (and that includes the steering wheel and the steering column) to access the mode actuator (which is the source of your B0249).

As an alternative, a Cadillac service department with a Tech 2 scan tool can perform a "recalibration" procedure on any or all of the HVAC actuators without removing any pieces.

Jim

Drive your car.

Use your cell phone.

CHOOSE ONE !

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Ok thanks for all the information. I'll have it checked out. If you dont mind could you tell me what going on with the other codes?

U1064 history

U1016 history

P1860

P0386

P0741

I searched and found what they are but I need some one to explain them. I'm not in a big hurry for them though so when ever you get time.

Thanks Drew

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U codes usually require no action. They can be set by an event as simple as a missed clock cycle.

P1860 - TCC PWM Solenoid Circuit Electrical. Translated this becomes - Torque Convert Clutch Pulse Width Modulation Solenoid Circuit Electrical. My ('04 Deville) Service Manual does not expand on this code so I will have to look in an earlier Service Manual for clues.

P0386 - Crankshaft Position (CKP) Sensor B Performance. Have you been experiencing random engine stalls? GM had a vendor problem with a batch of crankshaft position sensors. Failures can be expected.

P0741 - TCC System Stuck Off. This one could be related to P1860. And your MIL will be illuminated. This is not good news.

Jim

Drive your car.

Use your cell phone.

CHOOSE ONE !

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P0386 - Crankshaft Position (CKP) Sensor B Performance

There are two, "A" & "B" sensors. GM had a bad supplier (Mexico) and nearly every 2000 - early 2003 needs to be changed. It will generally cause an intermittent engine stall. Change them both.

P1860 - TCC PWM Solenoid Circuit Electrical

P0741 - TCC System Stuck Off

These two are probably related. Use the search button to do a search for TCC or P0741.

Don't worry about the "U" codes. Probably from pulling battery power.

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When i first start the car i can hear a knocking sound under the dash. Its like the gears are stripped. I can't swap from defrost to heat. I was wondering if I needed to change the gears out or if it is possible. Any information would be appreciated. Thanks Drew

Does the knocking sound change with the fan speed? If so I would pull the fan motor and check for a mouse nest in the fan. The nest could also block the actuator door.

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