I hope this is in the right post.
I have a 1993 chevy truck i swaped a 4l80e into, had a 4l60e
Howell efi did the computer and harness.
The truck has no 4th gear and no tcc apply, the scanner shows im in 3rd on the gear selector when i am in 4th. I checked all wires and are good. I can manually ground both solenoids at 55mph and it will shift into fourth, but still no tcc apply and yes the brake light wire is wired in and working. I am grounding them inside next to the ecm. I changed the ecm and no difference. Could it be the fluid pressure valve position switch? Should i be able to manually make the tcc apply by grounding?
Thanks for any help, I am stumped and no one has been able to help.