Looking at the schematic for reversing and it’s related components
#14,, since it’s the only fuse that fails, doesn’t have any power distribution/supply or have any circuit protections for anything other than those listed in the post above... I’d suspect or check all those related before looking elsewhere. If selecting reverse blew the fuse, different path...

Guess the part about unplugging the DTRs didn’t sink in..

With the DTRs disconnected, and a meter test on pin 9 on the unit, what value does it read?
It must be indicating a short when parked.. Or, is it indicating open?

Hayapower, i think we’re on the same page. If I check the other gear positions and they don’t blow the fuse that means the position(tr1, tr2, tr3a, or tr4) signal wire that’s energized in park is the wire that has the short. Right? Do you know which position circuit is complete when the trs is in position 6, park? Thanks

Hanky, I have not measured the current on the circuit. I assume the light blue/pink would be the power wire as the schematic shows it going to 14 from the trs. I just checked it with the light to verify power when I started to try to find the issue. When I get home I will test with the meter. I assume it’s a short because it blows instantly and with authority eg. wide open. Thanks

Hanky, I bought the trs sensors from 2 different auto zones. They said I could return them so I tried 2 different ones from different stores thinking one might be bad. The schematic I posted only shows the reverse circuit on the trs. There are others not shown. I am not a professional mechanic by any means, just a normal guy that does all his own work. When I rebuilt the trans I did not test any of the internal electrics. I just cleaned and lubed everything and reassembled. I have thought about the solenoids being the issue, but I unplugged everything from the transmission and it still blew 14 so it can’t be inside the transmission.

Hayapower, I agree. Pin 9 will be the first thing I check when I get home. In looking at the schematic you already sent, is pin 9 the reverse lamp power side?

Pin #9 and it’s color/tracer is on the schematic you posted above. LB-PK
I can send a connector view, but the reading taken on #9 may help..

Hayapower, that’s what I thought. I only hit it with a test light when I first started with this problem. I know it’s powered with the key on, but I will get a reading for you when I get home. Thanks.