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Insane Instrument Panel

My Daughter’s 2004 Chevy Impala has a defunct instrument panel. The speedometer sometimes works, other times either doesn’t work at all or gives very unrealistic reading. The Temperature guage needle reads upside down. Is this perhaps loose connections on the gang disconnect plug, or is the computer or a module at fault.? What must be done to remove the instrument panel?

A lot of instrument panel issues like this seem to come from a dirty or cracked ground connection. Beyond that I can’t help as I don’t know how your car is put together.

That’s a good possibility. Are you capable yourself of removing the instrument cluster, washing the connections with contact cleaner, and reinstalling the cluster? Typically it’ll be one strip connector on a ribbon cable that mates to the instrument cluster.

Stop by the dealer parts window and ask for an “exploded view” copy of the dash assembly. That should show you how to remove the cluster.

I believe the Impala has what are called stepper motors, they go bad, If you are handy you can pull the cluster and do them yourself, Different GM model but it took a couple of hours to do the job, and $22 for stepper motors, tach, speedometer and one other gauge on mine were whacko. Some places online will do it for < $100. No CEL, or other problems I assume.

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I’m guessing along w/Barky above, quite likely the instrument panel stepper motors have given up the ghost. Not an uncommon thing we hear about here. Common sense of course to check the connectors serving the panel first.

Thanks for replies. It does seem like I have bad stepper motors so I ordered a 6 pack of them from Amazon. $22, as stated by Barkydog. A youtube video also mentioned how often stepper motors go bad, and showed how to do the unsoldering and resoldering work for them. What is meant by CEL?

CEL = Check Engine Light

It’s such a common problem some pro shops even offer the service of soldering in new stepper motors, rather than just replacing the instrument panel.

I replaced all 3 stepper motors, now all gauges working properly, it seems. Will know for sure if she drives alongside her husband’s car to compare speedo readings, and I compare her engine block temp with temp gauge using my laser digital thermometer. I couldn’t really calibrate the speedo and temp gauge like they demonstrated in some youtube videos I watched, based on where needles were with engine off; with original steppers, the needles did not go back to “off position”. Temp gauge needle was upside down, speedo was at about 80mph! Again, thanks guys, for all replies, info, and advice. There is a CEL code - 171, lean system, but surely another issue from the formerly insane instrument panel!

Congrats on fixing those cranky stepper motors. A lean code is something different, unlikely to be related to the instrument panel. It means the computer is having to inject more gasoline than it thinks it should based on the intake air flow; i.e. a discrepancy between the air flow sensor data and the O2 sensor data. Shops would start out by looking at their scan tool’s fuel trim data.

That makes sense, for sure. but out of my league…My car, 2000 Buick Century 3.1L has the same symptom, starts & stalls sometimes, but no CEL code, yet anyway.

Have you cleaned out the throttle body and idle air control valve lately?
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No, never, but I will need to do that, after I locate the IAC valve. Thanks for tip

The P0171 could be a dirty MAF (mass air flow) sensor. You can get a spray can of MAF cleaner at most parts stores for about $7 and the MAF is usually located just behind the air filter box in the duct between the filter and the throttle body. Two screws and one plug to remove. Spray and replace.

Could also be a vacuum leak or any air leak past the MAF sensor.

Thanks for info. I have spray contact cleaner, I think its Ethanol/Methanol based. I could see if that cleans it. I’m thinking that with the comments made on the MAF sensor it requires cleaning periodically…and I should check the large duct connection going to the throttle body, but I always keep that big hose clamp tight…

Don’t use contact cleaner, it can damage the elements. MAF cleaner is alcohol based.

From the CRC MAF sensor cleaner Safety Data Sheet:

OK, I stand corrected. I still would not use contact cleaner. There is a coating on one of the elements that erodes off eventually requiring a replacement MAF. I would not want to take a chance on damaging that coating prematurely from an incompatible chemical.

I wonder if isopropyl antiseptic alcohol would work & be safe, and it’s a common household solvent

just get MAF sensor cleaner at the auto parts store. It’s only a few bucks