95 hard body 4x4 no reverse

[RT K_line]

I'm having an issue with my truck. I'm hoping it's an electrical issue. It quit backing up with no warning. It never slipped or gave any indication of a problem before it failed. Once though it did go into reverse like normal with no slip. I was checking power to the ecu pin# 26. Mitchell on demand shows there should be power at all times. But it doesn't. I checked the fuses and found no problem. Any help would be appreciated.

[pendulum]

I'm not familiar w/ the auto trans, but if you've got a component that's supposed to be receiving power and it's not, just move backwards through the circuit until you get to the electricity.