Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
Welcome, I'm Chris (aka Moose), my normal schedule online is around lunch and after dinner past midnight.
Did I understand correct you remotely powered the pump and it still would not run?
At the pump if the black/white wire is a good ground and powering the gray wire does not result in the lift pump running then the pump is faulty.
Is ECMB 20 amp fuse under the hood good, this powers the pump relay.
At the PCM connector 1 pin D8 dark green/white wire is this powered with the key on, it is the power signal to the pump relay.
Here is a wire diagram. https://dl.dropboxusercontent.com/u/90220402/k3500.pdf
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Hello again Chris here,