Electrical problems?

BRONSON420

MEMBER
2007 CHEVROLET SILVERADO
98,000 MILES

The truck listed above is a 1500. It all started when I had a transmission problem at first I lost 3rd gear then it just went completely out so I replaced it with a used transmission from a 2500 4x4 I had got from a really good friend I took it for a test drive after installing it and it drove great for about 4 miles then for some reason when I came to a stop to turn onto another road it went back to the same problem as the old transmission I had lost 3rd gear again so I limped it back home parked it and when I went to start it the next day and had no power to my dash so I attached my obd reader and it told me my ignition switch was bad so I replaced it and still nothing then I noticed some wires dangling from under the dash and when I moved them my dash would flicker so I chased them down to the BCM and noticed some of my wires were spliced I then had my brother fix some of the wires now I have my dash but no head lights and no starter so we bypassed the ignition switch with a push button start but it won't start I need a full detailed BCM wire diagram.

Tuesday, December 24th, 2024 AT 10:22 AM

2 Replies

AL514

MECHANIC
5,499 POSTS

Hello, is this the 1500 5.3Liter 2WD? The Body Control Module sends out an Accessory Wake Up signal on the vehicles network that signals the ECM, TCM, etc. To power up, so it might be that the signal is missing, so some more vehicle info and we can post the BCM diagrams for you. The BCM has 7 connectors, when you check the connectors make sure the key is Off before unplugging connectors and also verify the pins are tight inside the connectors and there's no corrosion.

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Wednesday, December 25th, 2024 AT 1:29 PM

AL514

MECHANIC
5,499 POSTS

The first 2 diagrams (1,2) are the network diagrams showing the Accessory Wake Up signal that comes from the BCM to signal the more important modules on the high speed Bus, the rest of the diagrams are the BCM connectors X1-X7 with each pinout. With the wiring hanging down from the dash, once you get this sorted out check all the fuses with a test light, there's a good chance some wires may have touched ground and popped a fuse or two.

https://www.2carpros.com/articles/how-to-check-a-car-fuse

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

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