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2007 chevy trailblazer_ss_3ss
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Well, about two weeks ago all I did was change my headlights. I put some xenon lights (hyper white) and I had no issues.

I was driving and I noticed all my lights were off. I get home, nothing works. No lights, dash lights, interior lights, and rear windows.

I've been without a car now for two weeks, and its been at my mechanic shop for that long. We cannot find the problem.

I cleared the codes, and this code "U1000" keeps coming up. There is no serial communication.



Please, and thanks trailvoy members!
 

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2006 chevy trailblazer_ls
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1,674 Posts
okay lets see check the ignition switch, see if your getting power to and from it look at the fuse panel in the back, check eveeryhitg there and check the 12v pos. cable comming form the batt. going to that. check the bcm connections too start there....
 

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Discussion Starter · #3 ·
okay lets see check the ignition switch, see if your getting power to and from it look at the fuse panel in the back, check eveeryhitg there and check the 12v pos. cable comming form the batt. going to that. check the bcm connections too start there....
All of the fuses were checked (front and back)

We are doing an ignition switch test right now (I believe?)

I will have him test the ignition switch, and check the 12v cable.

Where are the bcm connections?

Anything else?
 

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2003 chevy trailblazer_ls
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5,268 Posts
just throwing this out-- did you check the MEGA FUSE?
that provides power to the rear fuse box
 

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2006 chevy trailblazer_ls
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bcm is that wired looking thing nex to the rear fuse box stands up and the ECM should be on the driver's side of you engine... did you do anything to the truck recently? have you tried disconnecting power completely for a lil while and then reconnecting and see what happens?
 

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2004 gmc
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Even with a bad megafuse the truck should start. Smells like ignition switch.

2 weeks? :eek:

When you say no lights, did you mean no headlights, either? What if anything in the vehicle DID work? Gauges?

Anyway, the PCM (combined ECM and TCM in the I6) is on the driver's side of the engine. The BCM is just forward of the rear fuse block.
 

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2007 chevy trailblazer_ss_3ss
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Discussion Starter · #8 ·
bcm is that wired looking thing nex to the rear fuse box stands up and the ECM should be on the driver's side of you engine... did you do anything to the truck recently? have you tried disconnecting power completely for a lil while and then reconnecting and see what happens?
Even with a bad megafuse the truck should start. Smells like ignition switch.

2 weeks? :eek:

When you say no lights, did you mean no headlights, either? What if anything in the vehicle DID work? Gauges?

Anyway, the PCM (combined ECM and TCM in the I6) is on the driver's side of the engine. The BCM is just forward of the rear fuse block.
The truck started before today, my mechanic told me to leave the jumper on it for 10 minutes with the ignition on to see if that's the problem.

Okay, we found the problem, and it is the part infront of the fuse block under the rear seat.

I called a few part stores and they are telling me that is not the bcm.

Yes, no highs, no dash lights, some gauges work, no locks, no rear windows, and no interior lights.
 

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2004 gmc
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How are you sure that's the problem? Swap with another trailvoy?

Anyway, if you buy another BCM off Ebay or the dealer, it will have to be configured by the dealer and their tech tool to install the VIN and your list of options. Unless your mechanic has access to the GM tech tool and the latest flash updates.

The parts stores are wrong, I think. Item 3 is the BCM.

 

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2006 chevy trailblazer_ls
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id look and see if that power cable from the front of the car going to the read of the fuse panel is dabaged somewhere... could be your problem right there..
 

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2004 gmc
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One of the connectors going into the BCM (on the top)
PLEASE don't tease us with insufficient detail. What connector, and what pin? Who chose to experiment with it this way? We have access to schematics, and can trace any signal your mechanic suggests.

I'm guessing you put power to a BCM pin that didn't have it. You don't need to "bypass" the BCM, you just need to find why power doesn't get to it the way it was designed.

There are actually MULTIPLE fuses that feed 12V to the BCM for various functions.

Unless you're on a BCM output pin.
 

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Discussion Starter · #17 ·
That's not the problem, we found the problem.

We're trying to bypass it, and re-run a wire to the 6th pin on the top of the BCM.

If not, I found one for $50 my cost. (BCM)

Something odd happened though, as soon as we put power to the connector, one line down the green wires turned black instantly, but still has power..

I'm not very good at describing, sorry.
 

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Discussion Starter · #18 ·
PLEASE don't tease us with insufficient detail. What connector, and what pin? Who chose to experiment with it this way? We have access to schematics, and can trace any signal your mechanic suggests.

I'm guessing you put power to a BCM pin that didn't have it. You don't need to "bypass" the BCM, you just need to find why power doesn't get to it the way it was designed.

There are actually MULTIPLE fuses that feed 12V to the BCM for various functions.

Unless you're on a BCM output pin.
Can I call you?
 

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2003 chevy trailblazer_ls
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That's not the problem, we found the problem.

We're trying to bypass it, and re-run a wire to the 6th pin on the top of the BCM.
Something odd happened though, as soon as we put power to the connector, one line down the green wires turned black instantly, but still has power..

I'm not very good at describing, sorry.
What, no fire and smoke?????:(:(:(
 

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2004 gmc
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...as soon as we put power to the connector, one line down the green wires turned black instantly, but still has power..
This is no way to troubleshoot a trailvoy. It's turned into trailvoy abuse at this point. If burning a wire isn't a clear hint that your mechanic has NO IDEA what he's doing, then you missed something in your own technical training.
I'm not very good at describing, sorry.
Ummmm, and your mechanic is guessing and may torch your vehicle if you let him continue this way. Good luck.

I've suddenly lost interest in the proceedings here.

 
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