Digital cluster on 96 DeVille

[jndnaps]

The gage cluster in my 96 DeVille went out on me the other day. It went out for a few mins and came back on. Today it worked for a few mins and went out. Can't see my speed or anything. It's just the center cluster. The idiot lights along the top work, but nothing below that. Can't even check codes. What is the fix on one of these things?

Thanks

By the way, it took my dumb a$$ 15mins to figure out how to get on the forum since it's been changed. So nothing is easy for me.. LOL

[Cadillac Jim]

There are two simple possibilities for cluster lights going out. The first is, of course, a fuse. The instrument cluster fuse is a 20 Amp fuse in the trunk compartment fuse block, which is on the left side of the rear of the back seat. The next most likely thing is a problem with the dimming control on the headlight switch; you can try turning or wriggling it around. Its connector may be loose or off, too.

You might run your OBD trouble codes and post them here. That may tell us something, like whether a fuse is out and which one. The link in my signature block goes to a Caddyinfo page with instructions on how to do that.

[winterset]

There are two simple possibilities for cluster lights going out. The first is, of course, a fuse. The instrument cluster fuse is a 20 Amp fuse in the trunk compartment fuse block, which is on the left side of the rear of the back seat. The next most likely thing is a problem with the dimming control on the headlight switch; you can try turning or wriggling it around. Its connector may be loose or off, too.

You might run your OBD trouble codes and post them here. That may tell us something, like whether a fuse is out and which one. The link in my signature block goes to a Caddyinfo page with instructions on how to do that.

during the daytime, the dash lights are on max, and there is no way to dim them - so that will rule out the dimming POT.

what happens when you press the "Display" button on the left to turn the display on or off?

Since you have no display screen, you CANNOT CHECK CODES - which makes this one tough.

Hopefully it's a fuse, or a connector. Did you have work done recently that might have upset some wires?

did you try disconnecting the battery at ground & re-attaching it?

At worst, I have seen complete clusters on ebay for as low as $35 with $15 shipping.

being that it happened before & fixed itself, I'm leaning towards a faulty wire or connector.

[jndnaps]

They worked a few mins and went out, then came back on a few mins later. That was yesterday. Today they were out when I started the car, but came on a few mins later and went back out a few after that. It's not the dimmer switch because the radio lights up fine and the lights for the A/C temp still works and they dim when I try the switch. Not a fuse either I'm sure. Unless it's loose somehow. If I can catch it on, I can check codes. It doesn't flicker on and off when I hit bumps either. I haven't had any work done to the car recently and the battery is charging fine. When it went on I was driving and checked that in the info center. I'll try disconnecting the battery tomorrow. I've heard getting one from a junk yard or ebay, I'll have a problem with the security settings. Just wondering if this is a common problem and hoping something easy to fix. Really hoping to hear that the wire always comes unplugged or something like that. Not my kinda luck though.

[Cadillac Jim]

You should be able to check the codes in the daytime when all the lights are on full. What happens when you press [OFF] and [WARMER] together for about five seconds? All the warning lights (except Service Engine) and all the segments on the information display should come on for about five seconds. If you see the DIC segments you can check the codes. If this is the case, pick a time when they work when you turn on the key and run the codes right then.

The dash lights are not on the dimmer when the headlights are on. When the headlights come on, the dimmer does determine the brightness of the dash lights. If some lights set by the brightness control work, and the dash lights work when the headlights are off but not when they are on, well, that sends me to the schematics in the FSM.

There are three fuses, all in the trunk compartment fuse block, shown in the 1997 FSM page 8A-117-0: CLUSTER (20 Amp), RLY IGN 1 (10 Amp), and IGN0-BODY (10 Amp). There's an IGNITION 1 relay in the trunk compartment relay center#1 that proviides power to the RLY IGN 1 fuse and the air bags.

On page 8C1-64, under "Dimming inoperative/improper" the 1997 FSM says that the dimming circuits are short-circuit protected. If a short exists anywhere in a circuit, the voltage shuts down. The way the dimming works is that the IPC reads the dimming level, then sends the data through the network to the radio, phone, and climate control panel. So, the dimmed circuits on the instrument panel, radio, phone, and A/C panel are all separate, but if any of them work then the dimmer pot is OK and the instrument panel module is OK. The IPC directly powers the dimmed lights to the electric windows switches and the door lock switches.

The PRNDL lights are powered separately from anything else. Do they dim properly?

Poking around in various places in the 1997 FSM, the plasma lights in the IPC are powered through the RLY IGN 1 fuse and IGNITION 1 relay. If your wipers work, your IGNITION 1 relay is getting power.

[jndnaps]

OK, I went out this AM and started the car. The cluster came on and went off within like 2 seconds. When I say off, I mean you don't see anything at all day or night. Lights on or off. Wipers work fine. The radio, climate control lights to the right and the average mpg or what ever is on the left side work. The PRNDL does not show. The turn signals work, but the arrows don't blink on the center cluster. The only thing working on the center cluster are the idiot lights at the top. Anything below that doesn't work when it goes out. So I can't see the PRNDL, Gas, message center, spedo or miles on the car. I let the car run a few mins and it came back on. I was able to check codes. I got the PC0603 and the RS0061. Those I always have. Now there is also PC1520 and PC1574. all are history codes. I just discoed the battery so I'll see if that helps.

[Cadillac Jim]

Old, chronic:P0603 Control Module Long Term Memory Reset

B0061 Roof Rail Module-Left Deployment Loop Circuit

New of late, perhaps related:

P1520 Transmission Range Switch Circuit

P1574 Stoplamp Switch Circuit

I guess PC means PCM, and the codes are P[owertrain] codes, and RS is restraints, because B0061 seems to be a seat belt code. Neither of these codes reflect anything that will directly affect the IPM segment displays.

The most interesting thing to me is that, on page 8A-117-8 of the 1997 FSM, the electronic PRNDL module is shown as powered by a separate line from the IPC, circuit 1382, the PPL/WHT wire going through C301.

I see the schematic of circuit 147 on page 8A-11-19 that the IGN 0-BODY fuse, 10 Amps, in the trunk compartment fuse block, powers the electronic PRNDL, the climate control panel, the IPC and other stuff. One line powers the PZM so I expect that other codes would be thrown if this fuse was bad, but it's worth taking a look at. Most auto fuses are built so that you can shine a light on them and see if they are blown without removing them. If the rear defogger comes on, this fuse is OK.

The smoking gun is circuit 1039. That schematic is on page 8A-11-23 in the 1997 FSM. If the cruise control works, this fuse is OK. Note that you must be over about 45 mph for the cruise control to work.

I'll look at the P1520 stuff on pages 6-552 through 6-555. The transaxle range switch generates four signals that provide the PCM with the gear selection. They are (1 means open and presumably pulled up to 5 Volts, 0 means grounded, on lines A, B, C and D respectively:

P 0111

R 0011

N 1010

D 0001

3 1000

2 0001

1 0100

The DTC is set if an illegal combination (one not in the table) is detected for 3.3 seconds. Note that none of them are 1111 or 0000 so a shorted or open connector is always flagged. I don't see any actions that would result from this DTC that would affect IPM segement illumination.

The other new DTC, P1574, is set when one of the rear wheels slows down too quickly when the brakes aren't on. If it's HISTORY, we'll ignore it; it doesn't seem related to the IPM segment display.

This all seems to show that the DTCs don't tell us anything about the IPM display segments being intermittent. That's news it itself, though. It gets us back to the troubleshooting steps in the 1997 FSM on page 8A-117-14, "VF Displays Do Not Light." The troubleshooting process says to check for 12 Volts on circuit 1039, which is powered by the RLY IGN 1 fuse (10 Amp) in the trunk compartment fuse block (page 8A-11-23) and the IGNITION 1 relay in the trunk compartment relay center No. 1 (page 8A-10-12). That in turn is powered by a Maxifuse, IGN 1 (50 Amp) but if the wipers work that Maxifuse is OK. So, you need to look at the IGNITION 1 relay and the RLY IGN 1 fuse.

If you can verify that the cruise control works while the display is out, you have verified that circuit 1039 is OK and you don't need to deal with the trunk compartment fuse and relay blocks. That will leave the connector C1 (note typo on item 2; connector C3 should be connector C1) terminal A3 (connector end diagram on page 8C1-22), the pink wire. If it has 12 Volts on it, and the terminals are clean and not pushed into the connector, and the pin A3 on the IPM isn't bent or broken, then the IPM is bad.

[jndnaps]

Thanks for the info. Since I disconnected the battery it's been working. I cleaned some corrosion from the Neg cable and kept the batt discoed for an hour or so. Since then it's been fine. Although the battery died on me tonight after I washed the car. I have it on a trickle charge right now. Don't know why the battery died though. Cable is back on tight. I don't drive a lot and the car will site for 4 or 5 days at a time. When I do drive it, I go to the store around the corner. Don't really drive around a lot. Last I checked, the battery was charging at around 13 or so according to the info center. Maybe it has something to do with the battery? It's only 1.5 years old. If it goes out again I'll check the cruise. The wipers worked on or off so that was fine.

Today I scored 2 used vogue tires for $85.00 mounted and balanced. Lots of rubber, They're like 85%.. I needed two new ones and these suckers are like new. Great score for me there. Wish they had a set of 4..

Thanks again for all your help..

[Cadillac Jim]

Uh, oh. Low battery means all bets are off. I'm surprised that you didn't get some low-voltage codes, though. If it drops below 9 Volts on starting, or if it goes below 10.5 Volts after starting up, you will get trouble codes.

The bad ground would have been giving you low voltages and noise on the electrical system. This makes most troubleshooting pretty much like looking for a cricket in a trainyard.

Definitely get the battery checked out. You might consider a trickle charger or small battery maintainer to keep it fully charged. That will extend your battery life too.

[winterset]

Uh, oh. Low battery means all bets are off. I'm surprised that you didn't get some low-voltage codes, though. If it drops below 9 Volts on starting, or if it goes below 10.5 Volts after starting up, you will get trouble codes.

The bad ground would have been giving you low voltages and noise on the electrical system. This makes most troubleshooting pretty much like looking for a cricket in a trainyard.

Definitely get the battery checked out. You might consider a trickle charger or small battery maintainer to keep it fully charged. That will extend your battery life too.

If you still have troubles,

Disconnect the ground again, then take the red + off the battery. remember how they go, then separate the + cables out of the red plastic insulation, and clean the round contacts front and back. could be the starter is getting the juice, but the wires for the rest of the car are corroded & making poor contact. use a wire brush and/or sandpaper followed by wiping it down with a cloth to remove rust & green corrosion. the reconnect the red terminals to the battery followed by the ground. also check the ground where it connects to the car & make sure it is clean and not corroded.

[jndnaps]

Well it went back out again today. I didn't get to check the cruise control, I'll check it later tonight when I go back out. I'm sure I'm gonna have to replace that cluster. I was doing good with the car for a while with no repairs. I'll also get out there and check the positive cable and the ground. Everything else works fine so it'll probably need some repair or replace it. Will also hit a bone yard Tuesday too.. I'll see if there are any there. I read on another board that I can get a used cluster and use just the center of it. Then I'll still have my original odometer reading.

[BodybyFisher]

The next time it comes back up check the codes or use a hand held reader if you have not done so already, maybe something will show up

[jndnaps]

It's been out all day today. Just got back and it didn't work at all again. Was able to try the cruise and it did work and the wipers did again too. I don't have a hand held scanner. Can I go to a parts store and have them check it? Discount or Autozone maybe? I'm also gonna go by a spedo repair place on Tuesday and see what they have to say. It really sucks not knowing how fast you're going. Plus, it was kinda strange driving with that thing blanked out at night..

[Cadillac Jim]

You check the codes without a scanner in a Cadillac. On the A/C controls, press the [OFF] and [PASS WARMER] buttons together for several seconds, then all the dash warning lights and message display segments (except Service Engine Soon) will come on for a few seconds, then the message display will begin cycling through the ten or so modules in your car, displaying either something like NO PCM CODES or the codes set by the module. Instructions on Caddyinfo are linked from my signature block.

[jndnaps]

You check the codes without a scanner in a Cadillac. On the A/C controls, press the [OFF] and [PASS WARMER] buttons together for several seconds, then all the dash warning lights and message display segments (except Service Engine Soon) will come on for a few seconds, then the message display will begin cycling through the ten or so modules in your car, displaying either something like NO PCM CODES or the codes set by the module. Instructions on Caddyinfo are linked from my signature block.

Yes, I know how to do that. I can't check it if the cluster is out again. I forgot to quote "Bodybyfisher" He mentioned a hand held reader.

[rockfangd]

now I am fairly sure that the mileage is in the PCM so changing the cluster should not affect the odometer.

I am also not sure if you can use a salvage cluster as It may be programmed into the BCM.

[jndnaps]

I heard that if I get a bone yard cluster, I'd have to take the car to the dealer to get it to work. I read that I'd have to have it reset or programed to work in the car and that the car wouldn't start due to security issues. Kinda like trying to put another radio in the car. Gotta get it reset. I may still try that. The spedo place wants $300 to fix it..

[Cadillac Jim]

The mileage is kept in the IPC, according to the 1997 FSM page 8C1-13, in the last paragraph under Instrument Panel Cluster (IPC) Overview. I think that the IPC is the master computer for the whole network, if you can designate any one module as the master. The EEPROM in the IPC also holds the VIN and the calibrations of all the sensors like the gas gauge sending unit, the several temperature sensors, etc. All the options on that particular car are also stored in the IPC EEPROM. If you replace the IPC, the dealer can recover this data for your new IPC.

[rockfangd]

The mileage is kept in the IPC, according to the 1997 FSM page 8C1-13, in the last paragraph under Instrument Panel Cluster (IPC) Overview. I think that the IPC is the master computer for the whole network, if you can designate any one module as the master. The EEPROM in the IPC also holds the VIN and the calibrations of all the sensors like the gas gauge sending unit, the several temperature sensors, etc. All the options on that particular car are also stored in the IPC EEPROM. If you replace the IPC, the dealer can recover this data for your new IPC.

Thank you that is correct. Upon dealer programming they can recover.

I am in the process of getting a FSM for my cadillac so I can read for awhile.

[Logan]

The mileage is stored in the IPC.

A GM dealer cannot program the mileage in the IPC.

The GM Tech 2 cannot program the mileage in the IPC.

You need to take the IPC to a Delco radio/speedometer repair shop to program the mileage in the IPC. A reman IPC is typically about $300 exchange at a Delco shop with you walking in the IPC.

[jndnaps]

Well thanks for the info. I really haven't done anything with it yet. One of my oldest friends died last week at work and I pretty much lost interest in anything. Once I get out of this funk I'll get back to it. Thanks again for the help.. I'll let you know the outcome.

[BodybyFisher]

It's been out all day today. Just got back and it didn't work at all again. Was able to try the cruise and it did work and the wipers did again too. I don't have a hand held scanner. Can I go to a parts store and have them check it? Discount or Autozone maybe? I'm also gonna go by a spedo repair place on Tuesday and see what they have to say. It really sucks not knowing how fast you're going. Plus, it was kinda strange driving with that thing blanked out at night..

Hmm, now that I think about it, unless its a P code, its not likely that a hand scanner would retrieve B codes, but look into it. Most hand scanners only show P (powertrain) codes.

I guess that means that the next time your panel works you need to retrieve codes immediately, maybe there will be a history code, or you can go to the dealer and have them plug in a Tech 2

[rockfangd]

off hanf the only scantools I have ever used that pulled B and other codes was the Genesys or the OTC top end scantools, but I am sure there is others. I have a snapon one that does not.

[jndnaps]

My next question would be how do I get the cluster out? Does anyone have a diagram of the dash and all? There's a 96 DeVille in the bone yard and I broke the wood around the A/C vent on the left side. I know that has to come off and don't want to break mine. Does the dash pad have to come off too?

[jndnaps]

Anyone?

My next question would be how do I get the cluster out? Does anyone have a diagram of the dash and all? There's a 96 DeVille in the bone yard and I broke the wood around the A/C vent on the left side. I know that has to come off and don't want to break mine. Does the dash pad have to come off too?