Chassis Electrical Problems

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biscuitWizard

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Hello everyone!

I'm really glad to have bought a Pontiac, I haven't ever loved a car as much as this since my first car. (A Cougar. Show disdain if you must! But the V8 was just so fun. :)) I've been spending a lot of time working on it, doing general maintenance work and getting everything up to snuff so it will pass inspection.

There's just a few problems I can't seem to figure out, though.

One is that the left headlight does not come on, but both highbeams do come on. I checked the fuse and replaced the relays with no success. I thought it might be the sockets, so I removed those and replaced the headlamps and the sockets. It was then that I discovered the previous owner ran a wire from the right headlamp to the left in order to get it to work, and I removed that wire. No hacks here. :P I began tracing the system looking for shorts and examined the harness, seeing no imperfections in the wire casings as far as I can see. (There's a point that it runs under the battery and I can't see it anymore.)

Is there anything I can check to locate why it won't turn on?

There's also a few other oddities. While driving, electrical components will turn off and on if there's a high power draw. (Stereo loud, highbeams on, etc.) The dash cluster will turn off and on. The stereo will turn off and on, the lights will go dim, so I don't know what's happening there. I thought it might be the alternator or battery, so I brought it into a shop to have it tested. The alternator is fine.

The battery however went to 8v during draw, and the tester said it was a "Bad Battery". So we replaced the battery, and sure enough the draw was back to correct levels with the new battery, but the new battery still had the "bad battery" error from the external tester, so there's probably a short somewhere that I can't find, yet. I don't have any more information regarding the tester, other than it was just a computerized device. Maybe it was faulty? But there are issues here, so I don't know. Replacing the battery didn't fix the issues. :/ (But it was worth replacing anyways. Now I have a battery warranty. Go Interstate.)

When I got the car, the stereo didn't work. The 20A amplifier fuse was removed. Replacing that was easy. Didn't know why it was removed, maybe the previous owner knew something I didn't or was trying to alleviate the power draw issues. I am not using an expensive set of aftermarket stereo equipments. All factory, save for the headunit.

The car itself is a 5-speed standard 2001 Pontiac Sunfire. I do love this car to bits, and will spend whatever time I need to, to find this problem. But some tips would be greatly appreciated so I'm not as blind as I feel right now.

I have a digital multimeter at the ready! So hit me.

~ Julie
 
Does your service vehicle soon light (service with a little wrench on the left side of instrument cluster) stay on after you crank the car? Does your DRL indicator flash after cranking? Did you replace the stereo HU, or was it already aftermarket when you bought it?If the car didn't come with the Monsoon radio system, you probably never had a fuse in the amplifier location of the fuse panel. I would remove the battery, and look at the harness where you said you lost it under the battery. Check for worn insulation, etc. Also, there is a grounding point usually right by or under the battery compartment, check it for corrosion and tightness at the body. Other than that, you might have a weak voltage regulator in the alternator. I have seen them check good on a tester, but still not be able to keep up with the load that's being put on it in the real world. I'm sure some others will chime in with suggestions as well. Good luck with diagnosing the problem.
 
The light stayed on after cranking. The PCM was recently replaced. When I got the car, it had the monsoon head unit in it. I removed it and added an aftermarket stereo because the stereo wasn't working (I should've checked the fuses first! Doh. But I needed the aux in anyways..) It still didn't work after we put in the new stereo, so I checked the fuses and adding the amp fuse turned the stereo sound on. So I suppose there's another amp somewhere in the car for the monsoon system. I think tomorrow I will look for it to dig it out.

The headlights flash when the car starts, so I suppose that the DRL indicator?

I'll check those things when it's actually daylight and not raining! So hopefully today.

I took out the dash and found out the bulbs were burnt out behind the cluster, so I'm going to replace those with some LEDs since they're SMD.
 
Did some more digging around in the car day. Removed the instrument cluster trim and everything so I can replace the cluster when it arrives...

Tested the Lft headlight fuse and got 0.0v. Rght had 0.98.

Now here's the interesting part... If the right fuse was in, the left fuse had 0.0v

If the left fuse was in, the right fuse got 0.08v.

If neither were in, there was no voltage to be had at either socket.
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You could have a problem with the BCM (Body Control Module) Here is a pinout/ wiring diagram for an '00, it should be the same for yours. http://www.justanswer.com/pontiac/337j8-need-2000-sunfire-bcm-wiring-diagram.html

Notice that there are two grounding points for the BCM, you should check those for corrosion and solid connection. The one under the battery tray is known for becoming corroded. you might want to look under the dash, and unplug the BCM, and look for any corrosion on the connector there as well. Do you have a check engine light on? You say some IP bulbs are blown, so you might want to have the car scanned to see if there are any codes set, especially body codes.
 
Yeah. I tried a different IP today and the dash lights came on and it didn't blow, so I think the dash lights might just have needed replacement or something... I removed a blown bulb and did a multimeter test on it and the voltage was super fine. 12v. (11.56+ area)

I'll have an OBD-II reader here in about a week, so I can check the codes then. Until then, I'll look into checking the connections.
 
I ended up hooking my obd-ii scanner in today and bazinga, error codes.

B1295, B1254, U1301.

I also ended up replacing my instrument panel today. (Picked up a broken panel from a car that had a head-on collision. The clear part was broken but the circuit and face were intact. Swap the shields with a spare Canadian IP I had laying around, and bamf. Working IP in Miles instead of KM. Also shows mileage now. 163xxx.)

After getting the error codes, I sifted around the engine bay more and found a loose connector from the negative battery terminal that looks like it needed bolting down to the battery tray. So I bought a bolt and bolted it down.. Then I tested the car by running with highbeams on, ac on, stereo full, and nothing quit or shut down.

There are probably still other problems.
 
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