dash instrumentation behaves irregularly, why?

[mywitchywoman]

Hello,

On our 2003 GrandAM SE1 we are having a problem with our dash instrumentation. It began with our fuel guage not moving occassionally after starting, and continuing to not work until the next time we started the car. Now it has progressed to the point that the dash instruments don't work when we start the car about half the time, until we have driven a mile or more. Then all the needles and odometer/tripmeter begin to work.

Does anyone have any good ideas of why this would happen? My only guess is a poor connection, but I don't know where to look for the most likely candidate to remove, clean and reinstall.

A weak battery wouldn't do this would it?

Thanks for any/all tips you can give.

[440Brian]

My daughter's 2001 had those syptoms, the windows wouldn't even work. I found the ignition switch was intermittent, probably the contact that supplies power to the BCM. I replaced the switch and it's worked perfectly since.

[rixGAphx]

Witchy, it's prolly a faulty ground from the Instrument Control Panel (IPC) to the body.
Or from the body to the battery, but that would *prolly* cause even more symptoms.
Nonetheless, battery cable service is always important on the GA, and relatively easy, so do that first.
The procedure is here, under the site FAQ menu tab: http://www.gaownersclub.com/forum/faq.php?faq=maint_repair#faq_batt_serv
* * *

There are 3 major different things happening in the IPC:
* Nightime illumination, 12v controlled thru the dimmer switch.
* Idiot lights, gage needles (except fuel level), and odo/trip data; comes as a 'data stream' at 5V from the PCM and goes into a little microprocessor built-in to the IPC; can't be repaired.
This IPC microprocessor gets its own 12V power from the ignition switch (with which it operates and converts the PCM 5V data so it can do actual 'work', like lift a gage needle), then grounds-out to the body.
* The fuel level gage, which gets 12V directly from the sender (inside the fuel tank, which gets the power from the ignition switch) and then grounds to the body after the gage.

The problem *might* be with the ignition switch as 440brain suggests, and lord knows these cars have problems with that switch.
But the fact that your problem, though similar, progressed in 2 different steps (fuel gage, then other stuff) suggests to me that it's a problem with faulty grounding.
All the dash stuff on cars *usually* grounds to one or 2 'common grounds' on the firewall, under the dash (on some cars, the ground wires go through a rubber grommet in the firewall and ground to sheet metal in the engine bay).
Sorry, I don't have wiring diagrams available for '99+ GA's.
Mebbe somebody lse can chime-in; I know somebody was offereing wiring diagrmas on this forum recently, he needs exact info on model/year/engine/options and where you want to look.

As I stated in the thread "Help! Engine Temp Gage,":
First step is always to unplug/re-plug the wiring connectors to make sure they're clear of foriegn matter.
Second step would be to check the wiring in the area where somebody might have been working (like installing a stereo under the dash) shortly before the problem was first noticed.

Hope this helps,
-Rick