Electrical issue outside of my wheelhouse
Electrical issue outside of my wheelhouse I am not very experienced with electrical issues so I thought I would post this here to see if anyone had any suggestions. I have an 2002 Trans Am that I am just finishing up a H/C/I swap on. This problem has existed since I bought the car 6 months ago and before I started the work and I am not really sure where to start looking for the culprit.
I have something that is slowly draining the battery over a 3-4 day period if I don't start the car. There are a couple of other notable issues that I will mention that may help you help me. The head unit (the factory one is still in it) doesnt work. The digital face and buttons light up but it just puts out static. While the digital face will light up, it does not display anything (time, stations, etc). I also noticed the the courtesy lights do not turn on, nor does the power antenna work. You also can not turn on the map lights manually. Power windows, seats, locks, wipers, A/C etc work fine. All of the exterior lighting (headlights, taillights, turn signals, etc) work fine as well. Any suggestions on where to start with this?
I have something that is slowly draining the battery over a 3-4 day period if I don't start the car. There are a couple of other notable issues that I will mention that may help you help me. The head unit (the factory one is still in it) doesnt work. The digital face and buttons light up but it just puts out static. While the digital face will light up, it does not display anything (time, stations, etc). I also noticed the the courtesy lights do not turn on, nor does the power antenna work. You also can not turn on the map lights manually. Power windows, seats, locks, wipers, A/C etc work fine. All of the exterior lighting (headlights, taillights, turn signals, etc) work fine as well. Any suggestions on where to start with this?
Last edited by Mike TA; Jan 7, 2016 at 12:05 PM. Reason: error
Launching!
Joined: Apr 2015
Posts: 237
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From: Henderson NV
Usually the way you do this, is you put an ampmeter on the positive battery cable and see if there's a drain. If you find a drain (several hundred mA) then you start pulling fuses until it stops. Then at least you know what section to start investigating.
Generally for safety reasons you use the negative terminal. Remember most car batteries give off hydrogen gas, and touching the positive like that will cause a spark. I've seen batteries blow up because of that and battery acid to the face is not fun.
How old is the batt?
How old is the batt?
Wells just did a webinar on diagnosing this sort of problem. It may be useful to you:
https://www.youtube.com/watch?v=DBBh...ature=youtu.be
https://www.youtube.com/watch?v=DBBh...ature=youtu.be
Generally for safety reasons you use the negative terminal. Remember most car batteries give off hydrogen gas, and touching the positive like that will cause a spark. I've seen batteries blow up because of that and battery acid to the face is not fun.
How old is the batt?
How old is the batt?
No problem. Generally on a stock car with no aftermarket electrics yooy won't want anything over 30mA of draw. If you do, start pulling fuses and see what drops it. Make sure to let the electronics settle as well, oftentimes when you hook the meter up the electronics reactivate for a bit, giving you high readings. Let it sit for a few and it should drop.
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Thanks for the tip guys. Between the time that I posted this and the time I started to get advice I switched out my head unit. The factory one was busted. It appears that was the issue. Perhaps there was a ground or something that wasn't solid. I didn't get a buddy, who is good with electrical stuff, over here with a multi-meter until after I changed out the head unit. With everything shut down (the car had sat overnight) it was pulling just at 30. We will see how it goes.
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