When you turn the key the only thing that comes on is the check engine light?

2004 CHEVROLET COLORADO
350,000 MILES • 3.5L • 5 CYL • 4WD • AUTOMATIC
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04COLORADOZ714X4
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When you open the door there is no chime, when you turn the key the only thing that comes on is the check engine light. You can hear a click on the top of the motor, like a pump priming. I changed the ignition, i have had trouble with it before. But that didn't fix it. BCM? Also, i had my windshield replaced and it leaks pretty bad, would that help fail the BCM? The truck was running and driving, shut it down to change transmission lines. And the truck sat for 6 months with the windshield leaking. I tried to shop vac it out and put a dehumidifier in my truck. No codes from obd2.

I have also taken out the bcm and inspected it, clean and nothing looked burnt or discolored. Hooked up the battery and tried the key and just the check engine light nothing else. No turn or start. Disconnected the wiring harness right below the bcm, (i think it runs to the back of the truck running along the running panel), and when I tried the key again there was no check engine light or anything else?

Any help will be much appreciated.

Thank you.
Aug 3, 2023 at 1:15 AM
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STRAILER
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It sounds like the battery is low so please make sure it is charged with the battery cables clean and tight. This guide can help us.

https://www.2carpros.com/articles/everything-goes-dead-when-engine-is-cranked

If this is not the problem the water damage to the BCM could be causing it but to be sure we need to do a CAN scan, you can get a CAN scanner (Controller Area Network) which will work on most cars from Amazon.

here is a video to show you how:

https://youtu.be/u-4syLc-ifQ

Here is how to change the BCM out, you can get a preprogrammed unit by searching Google or Ebay. You might want to try to dry out the electrical connectors as well.
Aug 3, 2023 at 7:13 AM
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04COLORADOZ714X4
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I got the Autel al319 today and ran a test, but i am not too sure what i am looking for. The unit did not come with an instruction manual?? So, i am going to try looking on the net.
Aug 5, 2023 at 3:57 AM
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04COLORADOZ714X4
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Do you know what i would be looking for?

Thanks,
Aric
Aug 5, 2023 at 3:58 AM
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04COLORADOZ714X4
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I ran the Autel al319 and it shows that there are no codes, and the readiness test states that evap,cat,hrt and 02s are not ready???
Aug 5, 2023 at 4:26 AM
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STRAILER
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Okay, did you check the main power fuses? And if they are okay, it could be the ignition switch. Let's use this guide to help test for power input and output when the key is on.

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

See if you have power to the orange wire, and then turn the switch on and test the outputs. Check out the images (below). Please let us know how it goes.
Aug 7, 2023 at 2:37 AM
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04COLORADOZ714X4
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I just installed a new ignition.
Aug 7, 2023 at 3:33 AM
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04COLORADOZ714X4
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I know there is power at the white with blackline wire. I will check all of them and let you know. So test with key to on, correct??
Aug 7, 2023 at 3:34 AM
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04COLORADOZ714X4
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There is power to all except blue and yellow.
Aug 7, 2023 at 4:55 AM
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04COLORADOZ714X4
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Also, i forgot to mention i found out that a wrench had touched both terminals, with a big spark happened while sitting.
Aug 7, 2023 at 4:57 AM
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04COLORADOZ714X4
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I have checked all the fuses and none were bad. Have power on both sides of mega fuse.
Aug 7, 2023 at 4:57 AM
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04COLORADOZ714X4
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Also, i have the airbag off of the steering wheel, does that matter?
Aug 7, 2023 at 4:58 AM
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STRAILER
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No that should not matter, do you have power at the orange / blk/white wire going into the ignition switch? here are the entire wiring diagrams so you can see where the main power comes from, I think this is your issue. Please make sure the battery is in good shape. There are several main fuses you need to test. Check out the images (below). Please let us know how it goes.

Aug 8, 2023 at 3:14 AM
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04COLORADOZ714X4
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One the driver side of the ignition is a black cap with the plug. The white wire with black line has power.
Aug 10, 2023 at 7:42 AM
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STRAILER
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Okay, with the key on the remainder of the wires should have power can you please test them? Check out the images (below). Please let us know what you find.
Aug 11, 2023 at 3:10 AM
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04COLORADOZ714X4
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No power at white and blue and white and yellow.
Aug 11, 2023 at 6:36 AM
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STRAILER
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It looks like you have found the problem, here is how to change the switch out. Check out the images (below). Please let us know if you need anything else to get the problem fixed.
Aug 12, 2023 at 2:05 AM
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04COLORADOZ714X4
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It did this with the old ignition and with one i just installed new.
Aug 12, 2023 at 5:03 AM
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04COLORADOZ714X4
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Does anyone know where to buy just the switch??
Aug 12, 2023 at 5:16 AM
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04COLORADOZ714X4
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How can i test the BCM?
And i just replaced the ignition assembly because my truck was just having the check engine light on and nothing else working, so upon installing the new ignition, i still have the problem???
Aug 13, 2023 at 7:23 AM
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04COLORADOZ714X4
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There is power on the blue wire to the BCM, but i do not know how to test if it is coming out, does the white/yellow wire from the ignition receive 5 volts from the BCM to then activate the white/blue to the run/crank??or does 5 volts. come from the ignition to the BCM? So stressed out.
Aug 13, 2023 at 8:47 AM
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STRAILER
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Sorry about that, yes it can be stressful. You will need to send the BCM for testing for it is difficult to test on your own. Did you test through the ignition switch? They are 12 volts only. Please let us know what happens.
Aug 14, 2023 at 5:21 AM
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04COLORADOZ714X4
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There is power to ignition wires wht/blk,wht/red and wht/grn.
There is no power at the ignition wires (wht/blue and wht/yellow) although when testing the white with yellow wire,
i believe that it receives or sends a 5-volt signal to or from the BCM (pass lock) then the white/blue would send 12v to run/crank?
Hence why i think it is the BCM.
Am i wrong?
Aug 14, 2023 at 5:37 AM
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STRAILER
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Nope, it sounds like the BCM. I would replace it with a rebuilt unit, you can get a preprogrammed unit by searching Google or Ebay.
Aug 15, 2023 at 1:32 AM
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04COLORADOZ714X4
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I got a new BCM, door chimes started working as soon as the battery was connected.
Aug 16, 2023 at 7:30 AM
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04COLORADOZ714X4
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Started the pass lock relearn. Turn the key to start, wait for the pass lock to stop, turn the key to off. Repeat,
I did 3 of these 3 consecutive times before i didn't get to turn the key off after the pass lock light turned off for about 1 minute. On the 4th time i turned the key to start and it did.... yeah.
But i thought you need to do these a complete 4 times and on the 5th time it would start???
So, when it started on the 4th time i panicked and shut it off. Only to turn the key to start again and the truck started but i noticed. That the pass lock turned off seconds after starting it.

I have no dash tachometer, display at the bottom, gauges, turn signals on dash (they work on the outside).
Also, 2 codes now (p0017 and p0315).
I cleared them and they are right. Back??

Thank you for the outstanding guidance.
And any more help will be very appreciated.
Aug 16, 2023 at 7:39 AM
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STRAILER
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Glad you could get it fixed, thanks for letting us know. Please use 2CarPros anytime we are here to help. We only handle one problem per thread, please post your new question here, you must be logged in.

https://www.2carpros.com/questions/new

Cheers, Ken
Aug 17, 2023 at 3:16 AM
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