P1780 (Transmission Control Switch) with electrical issues?

I recently had the box off my truck, installed new body mounts and installed a new rear bumper on my 02 double cab, and after completing those items I took the truck for a short drive the P1780 code came up. In addition the blinkers will flash fast but only after I either tun the headlights or, or after I have taken the truck out of park.

Last but not least, I hear a whining coming from the transmission at low speeds, but fluid level is good (also new fluid as of 5000 miles ago) .

Any ideas? Would a faulty transmission control switch cause some/all of these symptoms or is this likely a Grounding issue (maybe pulled something loose when removing bed or when lifting cab for the body mounts?

 

Sounds like you pinched a harness when putting the bed back on.

 

Thanks for the tip, I will check that out. Could that cause the whining sound in the transmission as well, or is that a separate issue from the electrical issues?

 

Maybe. Hard to say without hearing it. I don’t know what the response is to that code.

But, you have more than one electrical issue (trans code and fast blinking lights) so I would check all the wiring and connections first since this is something you messed with (intentionally or not) right before the issues started.