93 GMC K1500 tranny fuse

[Gerry47]

Tranny Fuse continually blows. 93 GMC K1500 4X4 (5.7) 4l60E. I have had temporary positive results (twice) by disconnecting all sensors in the tranny circuit (also temporarily disconnecting battery). Fuse held once for a couple days and last time for a couple miles. I found that when circuit is good that a testlight connected in the fuse slot did not light but when the circuit was bad that the testlight did light up bright. Tried unplugging all sensors and tranny plug with no effect on testlight status. Once the fuse fails I get DTC 12, 66, 67, 81 & 82. DTC 12 should be ECM is operating properly. DTC 66, 67, 81 & 82 are all tranny codes which I believe is due to loss of power from fuse. I don’t believe that this is a hardwire problem since it has reset twice nor a tranny problem because unplugging it had no effect. Is it possible that the ECM/PCM fails from a sensor imput and cause a short to ground and sometimes reset after battery has been disconnected? I have disconnected the battery on numerous occasion to clear DTCs but not sure if it helped my problem or not. (I don’t have another ECM available to swap out and verify it’s status.) Could the problem be in the ignition? Appreciate any suggestions or ideas since this is driving me crazy. Gerry47

[Gerry47]

Couldn't wait for professional advise. Dug into problem and found by removing wire harness that several wires were indeed burn out by the one hole strap top of driver side bellhousing. Pulled tranny harness up into engine compartment wrapped all exposed wires and now it works great.