Brake Switch not sending power to brake controller
June 23rd, 2021, 12:39 AM
#1
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Brake Switch not sending power to brake controller
Hi al,,
I have a 2008 Suburban 2500K only about 30k miles on it. It has multiple electrical issues so here is the first post.
The trailer brakes are not working. I traced the problem to pink power supply to the brake switch. This wire is energized when the ignition is on. According to the electrical wiring diagram this wire is fed power from fuse #43 from the engine compartment fuse box. That wire then goes to the I/P Left Junction Block and then to the brake switch. The fuse is good and this pink wire has power at the I/P Junction Block (assuming I am checking to correct pink wire. From the brake stop switch the wire climbs up under the dash to a connector and according to the wire schematic directly to the I/P Junction Box.
I actually broke my dash trying to pop off the cover. Bummer. At that connector there is no power. Between that connector and the I/P Junction box power is lost. I am tempted just to hook up a replacement wire but then this doesn't address what happened.
Has anyone lost power to this wire? It Is Pin B, circuit 239 on the electrical stop Lamp Switch Connector
the blue (white tracer) wire coming off the brake switch does not provide power to the after market brake controller when the brake pedal is pushed. I swapped out the brake switch with another suspected good switch and this did not fix the issue. What I cannot find is an electrical wiring diagram online to where I can see what purpose all wires serve that go to brake switch. I cannot determine why the blue / white wire is not working. The wire appears have no damage.
t
I have a 2008 Suburban 2500K only about 30k miles on it. It has multiple electrical issues so here is the first post.
The trailer brakes are not working. I traced the problem to pink power supply to the brake switch. This wire is energized when the ignition is on. According to the electrical wiring diagram this wire is fed power from fuse #43 from the engine compartment fuse box. That wire then goes to the I/P Left Junction Block and then to the brake switch. The fuse is good and this pink wire has power at the I/P Junction Block (assuming I am checking to correct pink wire. From the brake stop switch the wire climbs up under the dash to a connector and according to the wire schematic directly to the I/P Junction Box.
I actually broke my dash trying to pop off the cover. Bummer. At that connector there is no power. Between that connector and the I/P Junction box power is lost. I am tempted just to hook up a replacement wire but then this doesn't address what happened.
Has anyone lost power to this wire? It Is Pin B, circuit 239 on the electrical stop Lamp Switch Connector
the blue (white tracer) wire coming off the brake switch does not provide power to the after market brake controller when the brake pedal is pushed. I swapped out the brake switch with another suspected good switch and this did not fix the issue. What I cannot find is an electrical wiring diagram online to where I can see what purpose all wires serve that go to brake switch. I cannot determine why the blue / white wire is not working. The wire appears have no damage.
t
Last edited by dwebst02; July 1st, 2021 at 2:20 PM. Reason: Provided better details after acquiring electrical schematic
June 23rd, 2021, 9:21 AM
#2
alldatadiy.com has all the diagrams for yours. Worth the subscription price for a full shop manual. It lists the different wiring diagrams depending on what options your truck was built with. There are different diagrams for my '11 Tahoe for 2 different RPO build codes.
Brake switch may not be sending 12v out but low voltage signals to the BCM to trigger relays.
Brake switch may not be sending 12v out but low voltage signals to the BCM to trigger relays.
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