electrical problems - again [Archive] - GrandAmGT.com Forum

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hooligan
10-13-2008, 07:35 AM
hi guys. new electrical problems with the car (98 GT) that have me kinda stumped. started getting the random abs/air bag/battery lights flickering, so i did the normal routine of cleaning the battery terminals and cable ends. didn't help a bit. so, i replaced the negative cable as i found a touch of corrosion below the insulation. didn't help a bit. had the battery and alternator tested on the car by autozone and found normal values. kept getting the lights, so i had a shop pull codes for me. came back with C1214-electric brake control relay control circuit open and C1237-high system voltage.

i am thinking that the alternator is spiking the system with high voltage. the current alternator only has about 40K on it, but with as bad as the rest of the electrical system is on this car it might be bad.

so, should i just replace it? i am thinking this is the main component that could be causing the random power spikes...

mhaisley
10-13-2008, 10:16 AM
If the regulator is going out, even intermitantly, you will see voltage spikes, and things like what your describing can happen.

You can get a voltmeter that plugs into the lighter socket, and watch to see if this is happening. If it's bad, you'll probably see voltage in the range of 16-20 volts. That's actually really bad, and eventually you will boil the acid out of your batteries, and then you might have to replace it as well.

hooligan
10-13-2008, 01:13 PM
thanks for the tip, i'll try to pick up a cigarette lighter voltmeter tonight...

rocketfast123
10-13-2008, 02:36 PM
Was the car running when autozone checked your battery?

hooligan
10-13-2008, 02:38 PM
yep, car was running for both tests. not sure if the spike is intermittent, but it tested fine.

rocketfast123
10-13-2008, 04:04 PM
To test the battery the car must be off. If you have it running the alternator will keep the battery at 12+ volts. I going with old battery. On our 97 malibu when the battery was going, weird lights would would come on like ABS, and the SRS light. Because when the car does not have enough power it will kill off some systems like ABS.

gagt Mechanic
10-13-2008, 11:03 PM
get a dvom and dont trust autozone. I do not trust most checkers, my work uses a ed-18 and it dose ok with batterys but not alternators. batter checkers only check dc voltage. your alternator creates ac voltage then goes through a rectifier to turn it into dc then through a regulator to keep the voltage in range. if your alternator is allowing too much ac voltage through the rectifier it can cause those issues. 0-50 mv ac is normal, 50-130 mv rectifier going bad, 130-250 car problems, may take out battery, 250+ by by pcm. your car cannot use ac voltage. to check the alternator have the car at idle, turn your dvom to mv ac, connect comm wire to neg of battery, connect pos to the power output on alt. ac voltage will fool battery checkers some times also.