'99 Grand Am GT: IPC/Blower/Windows Intermittency

gdglass

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Hello All,

It's been a long time since I've been on this forum so I don't know whether this issue's already come up. I didn't see it.

So I have a 1999 Grand Am GT, ~178,000 miles and still going strong. I've been having a strange electrical problem of late though. Very often when I start the car, the instrument panel cluster (IPC) doesn't power up, i.e. it doesn't go through its "wow sequence", and the gauges remain dead. When this happens, the HVAC blower is also inop as well as the power windows. This does make some sense as these are all on the same circuit governed by the same 10A fuse (at least the fuse is labeled IPC and blower in the fuse compartment). Anyway, after driving a bit, the cluster will almost invariably power on and the blower will become responsive. Sometimes they go out again but they usually come back and so on. If, before starting, I cycle the ignition several times, the cluster will come up immediately maybe one out of five tries.

:confused:

This does not appear to be an intermittent contact as the thing is not blinking on and off. It's either completely off for minutes at a time or completely on for minutes at a time. I suspected a relay but I couldn't find one that governed this particular circuit. I also wouldn't suspect a suddenly pinched or worn wire as I would think the power would flicker or would be completely off.

Any ideas? Thanks!

G
 
Could it be an issue with the ignition unit where the key goes? (whatever it's called) Seems like the ignition switching is a variable. I thought relays would be for high amperage circuits like lights, horns and fans...
 
I would suspect the BCM, body control computer. Check the connector where it plugs into the BCM for poor contact.
 
Could it be an issue with the ignition unit where the key goes? (whatever it's called) Seems like the ignition switching is a variable. I thought relays would be for high amperage circuits like lights, horns and fans...
Thanks, Dane. You're right about relays. I was just trying to think of something that could cause an intermittent connection where the devices in question wouldn't flicker on and off. I thought maybe if a relay coil was sticky or something...
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I would suspect the BCM, body control computer. Check the connector where it plugs into the BCM for poor contact.
Thanks, Melsg. I'm not sure where to find the BCM. I used to work for GM in the early 90s and spent a good deal of time in car plants. My recollection of some of the cars I observed being build is that the BCM can be pretty buried. Granted, I never went to Lansing South, where the GAs were built, so I don't know for this car. Any idea where I can find the BCM?

G
 
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