2001 Chevy Malibu electrical gremlins

[Raswan]

Hey everyone,

My girlfriend has a 2001 Chevy Malibu with about 97k on it. Today, while driving suddenly the gas and temperature gauges went dead, and the doors (which have an automatic lock that triggers when you put the car in drive) unlocked themselves. About five minutes later, the gauges came back to life (though the doors remained unlocked). This persisted all the way home from the airport, for a total of about 8 cycles. Sometimes instead of going dead and staying dead or coming back to life to stay, the gauges would jerk quickly and then return to wherever they were.

Does this sound like a problem anyone's had to deal with at all?

Thanks in advance for any help.

 

[LTC8K6]

Alternator going bad?

Bad ground?

 

[marvdmartian]

Did you notice it doing it whenever you hit a bump? Loose wire? Not sure why the doors would unlock, as that should be tied in with the gear shift lever position......

Like you say, gremlins. Not the AMC variety. :hmm:

 

[Raswan]

Alternator going bad?

Bad ground?

I thought maybe the alternator too, but wouldn't the radio and other electrical components also be affected? I did read something about a bad ground on one forum elsewhere--is this something I can check myself, or will I have to bring it in?

To Marv-- Didn't notice any more prevalence while going over bumps. Happened all on 1-35, a straight shot.

 

[boomerang]

Don't throw parts at it in an attempt to fix it. In other words don't start replacing alternators.

IMO, this isn't going to get fixed without the technician having access to a wiring diagram for the car. I would take this car to the dealer or an independent shop that has a good electrical tech. You'll probably only find that shop through word of mouth.

 

[marvdmartian]

Don't throw parts at it in an attempt to fix it. In other words don't start replacing alternators.

IMO, this isn't going to get fixed without the technician having access to a wiring diagram for the car. I would take this car to the dealer or an independent shop that has a good electrical tech. You'll probably only find that shop through word of mouth.

Let me second that. Especially with electrical, it takes no effort at all to start throwing parts (and money) at a problem, with no results.

Years ago, I lived down the street from a place that specialized in automotive electrical problems. For $15, they would diagnose your problem. If you got it fixed there, they waived the fee.

I would look for some place that has a similar deal. :thumbsup:

 

[BUTCH1]

Sounds like something is shorting out to ground, confusing the BCM (body control module). Maybe remove drivers side door trim , expose wiring and look for anything rubbed or chafed to bare wire..

 

[Raswan]

Sounds like something is shorting out to ground, confusing the BCM (body control module). Maybe remove drivers side door trim , expose wiring and look for anything rubbed or chafed to bare wire..

Only the driver's side front? Or could it be a wire exposed in any of the door panels? The reason I ask this is her rear passenger side window motor cable got all tangled up in the motor about a month ago, and we rigged it with duct tape rather than get it fixed. But it was definitely being moved around a lot manually, so it's possible we snagged a wire there.

Edit: I'll pull the driver's side apart tomorrow and get back to you.

 

[Raswan]

Let me second that. Especially with electrical, it takes no effort at all to start throwing parts (and money) at a problem, with no results.

Years ago, I lived down the street from a place that specialized in automotive electrical problems. For $15, they would diagnose your problem. If you got it fixed there, they waived the fee.

I would look for some place that has a similar deal. :thumbsup:

I'd love to do this, but we're both down in Oklahoma in grad school and don't have any kind of reliable mechanic down here. I've already been screwed once, and have replaced her blower resistor motor myself rather than take it to a shop (and I'm pathetic at fixing things. Took me three hours to do it). I'm planning on called my family's auto electric guy back in MN tomorrow, on the chance he's run into it before.

Incidentally, I checked the fuse boxes as well as the ground that runs into the fuse box, and everything seems secure and functional. If I could get a hold of an OBDII reader and plug it in, would it tell me anything useful? My brother's got one, and I could get him to ship it down here for pretty cheap I bet.

 

[punjabiplaya]

check out a local autozone or w/e. They used to check codes for free, don't know if they still do though.

 

[pcgeek11]

I had a similar issue with an Isuzu Pickup. Dash and gauges would flicker go out and back on all by themselves.... ( The radio was never effected BTW ). The slip rings in the alternator were grounding due to wear. Autozone or Advance Auto can check the alternator free.

 

[BUTCH1]

Only the driver's side front? Or could it be a wire exposed in any of the door panels? The reason I ask this is her rear passenger side window motor cable got all tangled up in the motor about a month ago, and we rigged it with duct tape rather than get it fixed. But it was definitely being moved around a lot manually, so it's possible we snagged a wire there.

Edit: I'll pull the driver's side apart tomorrow and get back to you.

I have an 05 'Bu and that's where mine developed a problem, the power locks would pop up and down repeatably, the dealer found a short in the harness where it enters the door.

 

[PricklyPete]

Only the driver's side front? Or could it be a wire exposed in any of the door panels? The reason I ask this is her rear passenger side window motor cable got all tangled up in the motor about a month ago, and we rigged it with duct tape rather than get it fixed. But it was definitely being moved around a lot manually, so it's possible we snagged a wire there.

Edit: I'll pull the driver's side apart tomorrow and get back to you.

I would certainly start there since that happened recently and could very easily be related.

 

[Raswan]

Sounds like something is shorting out to ground, confusing the BCM (body control module). Maybe remove drivers side door trim , expose wiring and look for anything rubbed or chafed to bare wire..

So I checked the wiring on the door panel where the window has been acting up, and I didn't see any exposed wires at all. Question: If I disconnect the power connector to the window motor, and the short is along that line, would disconnecting it stop the short?

Incidentally, I also called my family's auto electric guy back in MN, and he did mention that it sounds like a problem with the Body Control Module (BCM). When I was checking all the fuses, I saw one (or maybe two) of the large block ones are labeled "BCM." 1) Is there any way one of those fuses or whatever they are could be causing this? 2) How large of a problem is it if the BCM is malfunctioning/fried? Is it something you replace or fix yourself, or would I have to bring it in? About how much (approx) are we talking here, if either is an option?

 

[Raswan]

I have an 05 'Bu and that's where mine developed a problem, the power locks would pop up and down repeatably, the dealer found a short in the harness where it enters the door.

Harnesses looks good too.

 

[Raswan]

bump

 

[Raswan]

bump

 

[Raswan]

bump

 

[Raswan]

bump

 

[BUTCH1]

So I checked the wiring on the door panel where the window has been acting up, and I didn't see any exposed wires at all. Question: If I disconnect the power connector to the window motor, and the short is along that line, would disconnecting it stop the short?

Incidentally, I also called my family's auto electric guy back in MN, and he did mention that it sounds like a problem with the Body Control Module (BCM). When I was checking all the fuses, I saw one (or maybe two) of the large block ones are labeled "BCM." 1) Is there any way one of those fuses or whatever they are could be causing this? 2) How large of a problem is it if the BCM is malfunctioning/fried? Is it something you replace or fix yourself, or would I have to bring it in? About how much (approx) are we talking here, if either is an option?

First, if it's a fuse it wont be an intermittent problem, they either are blown (open) or not. Second, it's hard to put a price on it, if it is the BCM you might be able to find one a a local boneyard for much less than a dealer. You might want to disconnect the motor temporarily and see if the problem stops. Might want to invest $20 and buy a DMM meter and look for shorts, my gut feeling is the BCM is just acting up due to a short somewhere but if you can find one cheap enough used you might want to try swapping it out..

 

[LTC8K6]

I'd start tapping, wiggling, and moving stuff around with the engine running to see if I could duplicate the problem.

 

[BUTCH1]

I'd start tapping, wiggling, and moving stuff around with the engine running to see if I could duplicate the problem.

That's actually a good idea, might help OP locate the problem area..

 

[Raswan]

That's actually a good idea, might help OP locate the problem area..

That makes a lot of sense, but are you guys talking about wiggling stuff just in that possible problem area in the where the window motor stopped working? Otherwise, I'm not sure where'd to poke around.

 

[LTC8K6]

You want to wiggle and tap in lots of possible places. The door wiring harness, the BCM area and the module itself, the fuse boxes, relay boxes, etc.

Wiring harnesses that you can reach under the dash would be good too.

Harnesses under the hood as well.

Often the problem will be near a connector or a junction or where the harness bends or where it passes through an opening.

 

[BUTCH1]

You want to wiggle and tap in lots of possible places. The door wiring harness, the BCM area and the module itself, the fuse boxes, relay boxes, etc.

Wiring harnesses that you can reach under the dash would be good too.

Harnesses under the hood as well.

Often the problem will be near a connector or a junction or where the harness bends or where it passes through an opening.

That's what the dealer had to repair on my car, where the wires go from the door back into the car one of 'em chafed itself to bare metal..