Weird automotive electrical issues.

January 23, 2009 9:35 AM

I'm looking for some ideas on the numerous weird electrical issues with my car.

My 2003 Chevrolet Impala has begun to show some odd behavior. The most troubling seems to be that the dashboard lighting never works. When the light sensor detects darkness and thus tries to turn on the dashboard lights, the gearshift indicator and radio LCD dim, and the dashboard lights do not come on. Manually turning on and off the interior lights doesn't seem to do anything, nor does dimming them. The interior cab lights do work, however.

Another odd symptom seems to be that when I roll the windows up or down, the voltage seems to drop way down (while the window motor is on).

Add to this the fact that sometimes when I start the car, the clock has been reset to 12:00, but not always.

Also, the check engine indicator has come and gone for quite awhile now (perhaps entirely unrelated).

I have checked all of the fuses, and they seem fine. I appreciate any suggestions!

posted by kingbenny to travel & transportation (8 comments total)

you're in a cold place, so check your battery often.
it may just be that you never got a new one and your old 2003 one is slowly dying. have you tried charging it overnight using a wall socket? how are the connections? any grime, dirt on them? (there is a way these are supposed to be cleaned using oil and warm water but I can't tell you exactly how to do that. a mechanic did that once for me and it worked wonders.) this is sort of what I'd hope for.

countdown until someone says 'car talk' ... ah well, I'll do it: call the car talk guys.
posted by krautland at 9:45 AM on January 23

Take the car to an auto parts store (NAPA, O'Reilly, etc; one of the major chains). They will put your battery on a tester, and they should do it for free. If your battery is good, it might be your alternator (battery is dead because it is never getting charged).
posted by ArgentCorvid at 9:53 AM on January 23

I will chime in with "get your battery checked" too. It is rare that a battery will have enough cranking amps to get the thing started but not have the juice to run your accessories, but something like that could happen.

You will want to check the battery (voltage and cranking amps). If you get a new one, think about buying a deep cycle battery (Yellow Tops from Optima, are supposed to rule the roost here).

You will also want someone to check the alternator.

If those show up clean, then there is a hidden electrical issue that will take some forensic electrical work to find.

Good luck!
posted by milqman at 10:00 AM on January 23

I would also check the battery cables for a loose connection or a bad cable.
posted by rfs at 10:37 AM on January 23 [1 favorite has favorites]

Check the connections, as krautland suggests. If the positive terminal is exposed to the air it can get crusty oxidant buildup on it. You can clean it up with a wire brush and it'll be okay.

If you don't see any white crusty stuff, then take the battery in to be checked.
posted by echo target at 11:20 AM on January 23

I agree with all suggestions to check the alternator. Your electrical symptoms sound very close to what I experienced in a car with alternator issues. If you're out and the alternator goes out, you are not going anywhere, the battery usually cannot be charged. Good luck!
posted by Elaisa at 2:27 PM on January 23

A co-worker's car had strange electrical issues this fall. Not exactly like yours, but similar in their scope and apparent randomness. A mechanic found that a mouse had chewed the wiring insulation.
posted by Snerd at 4:46 PM on January 23

I think you have two issue. The bulbs in the dash have blown or a somehow broken. In addition, your battery is on its last legs. The drop in voltage you see that triggers the clock to reset and the windows to draw seemingly excessive current are most likely signs of the battery losing effective capacity. Chances are, the clock gets reset when you start the car as cranking is possibly the highest load you have.

Get the battery replaced, and then see if the dash lights fix themselves. My guess is it is unlikely they will, but the coincidence is making you think this is something more odd than it is. The interior lights are not in any way connected to the dash ones, so playing with that switch will have no effect anyway. My guess it is either a connection under the dash, a broken wire or some way that one bulb has blown and is ruining the circuit for the others to work.

I can't see how this can be an alternator issue. Alternators have a separate warning light and wont trigger the check engine light, so if the battery light isn't on and your car continues working normally apart from this, I'd say it is almost certainly battery related. That the car seems fully charged (or I imagine you'd mention it) when you first start it seems to suggest the alternator is functioning. Over, rather than undercharging, may have caused the dashlight issue, but the voltage drop issue wouldn't appear.
posted by Brockles at 7:57 AM on January 25