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93 GMC K3500 6.5 Turbo Diesel 4x4 4L80E Auto. Recently the 10 amp IGN/ECM fuse is intermittently blowing with key on, this powers the ABS module and the transmission control module; when it blows the abs/brake light comes on and the truck defaults to 2nd gear only and reverse. OBD1, I have pulled codes 59, 85 and 87. Transmission fluid appears to be good. I have eliminated the throttle position sensor, ABS module, trans control module, all sensors on the transmission and internal harness in the transmission pan. Believe there is a short in the wiring harness somewhere grounding it out. Pink wire with black tracer. I am having a heck of a time finding a wiring diagram and don't have access to shopkey anymore.
Anyone able to pull up a legible and complete wiring diagram of the IGN/ECM circuit?
Is your ICM tied into the IGN/ECM fuse on this truck? Reason I ask is because I have a 92 Cavalier that kept blowing the ECM fuse as soon as you turned the key on and it was from an internally shorted ICM.
Get a one day subscription to Alldata DIY for your truck so you can look at the wiring diagrams to see what all is on that IGN/ECM circuit.
