What is this wire

[70GMCer]

Found this under the carpet.

Anyone know what this wire is for?

[chengny]

IDK how the circuit is currently wired/routed - but some modifications must have been done. As original:

The cut leads went to the switch for the backup lights.

DK BLU is/was hot from the fuse block (fed by the 15A TURN B/U fuse)

LT GRN supplied the B/U lamps - via the rear lighting harness.

Because of the presence of the grommet, it's likely that the transmission was changed from a 4 speed manual to either a 3 speed manual or an A/T. The B/U light switch used with a 4 speed MT is mounted on the transmission, while the other two types are located in the cab.

[70GMCer]

Originally Posted by chengny

IDK how the circuit is currently wired/routed - but some modifications must have been done. As original:

The cut leads went to the switch for the backup lights.

DK BLU is/was hot from the fuse block (fed by the 15A TURN B/U fuse)

LT GRN supplied the B/U lamps - via the rear lighting harness.

Because of the presence of the grommet, it's likely that the transmission was changed from a 4 speed manual to either a 3 speed manual or an A/T. The B/U light switch used with a 4 speed MT is mounted on the transmission, while the other two types are located in the cab.

That would explain why I have no backup lights then.

The truck is an original auto trans. So, is the backup light switch located on the column?

Is it a part of the neutral safety switch?

Thanks for the help on this...