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Suburban Body Control Computer?

Hello,

I am new to the forum and I need some assistance with some problems that have popped up on my 2004 Suburban. It all started las spring. I have a large inverter (12v to 110 V) in the back of my truck. I had an 8 gauge wire running from the battery to the rear inverter. I was traveling at highway speeds when the wire shorted to ground (I know I should have had a fuse but I didn't). As the truck filled with smoke the truck stalled. As I coasted to the shoulder crazy electrical things happened. My wipers came on, my a/c fan went to full blast, my electric locks opened and closed maybe 10 or 15 times. And I can't tell you what else went crazy. Lucky the large cable drained the battery quickly before the red glowing cable set the floor mat on fire.

I disconnected the shorted cable and used a battery jumper box to get started and back on the road.

I had been having a problem with electric windows being very hard to get closed and it seemed like all the window motors were wearing out. But since the short the windows and other things have been doing odd things. For example, normal operation when I turn engine off the interior light should come on. Now the inter light comes on sometimes and does not other times. same with door locks, used to unlock the second I put truck into park but now I have a 50/50 shot at doors opening.

I am just now getting around to checking things out. In searching your forum I see the body control computer controls some of these things. I just took drivers door panel off and removed the switch cluster from the arm rest. I took SOME of the cluster apart. I went as far as removing the bottom plastic cover and pulled the first PC board out. I didn't get to the point were I could see the contacts that the plastic open / close buttons push. I wanted to see if any corrosion but I stopped, fearing if I remove too much I was going to spring loose something and end up with a hand full of parts that I would need 10 hands to hold everything in place to reassemble.

After telling you all this I get to my questions. First any advise on trouble shooting the original hard to close windows problem? Second question, I assume my short problem played with the Body control computer, any advise on trouble shooting that?

Thanks in advance

Comments

  • kiawahkiawah Posts: 3,666
    Personally, since you had a major short like that, I'd start by verifying that the basic electrical is okay.

    - Have an electrical load test performed on your battery and alternator, to verify that the alternator is putting out the rated voltage and maximum current. You could have shorted out diodes in the alternator, or damaged some of the alternator control circuitry. They will also check the battery, to be sure that it is holding the rated voltage, and can deliver the cold current amps. You can usually get this done at the larger auto parts chain.
    - Verify that your battery connections are clean, no corrosion, and tight.

    - Then verify with a digital voltmeter, that while under load (current being drawn thru the blocks because devices are on and drawing power), that each of the fuse boxes have the battery voltage on their buss. This will eliminate the possibility that one of the main fuses or cables have a resistance in them, thereby causing a low voltage condition on the block buss.

    - Once you are sure that the basic electricals are sound, then I would recommend moving to the door switches as you have. Meter out the voltages with a digital voltmeter, both under no-load and load conditions.

    - Since you had a major short to ground, and all of the devices in the vehicle use that ground as current return path back to the battery, there's no telling what all might have been damaged. You are just going to have to isolate and repair them one at a time.
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