Backup light connections

[david7w5@gmail.com]

I have a 1972 Chevrolet C30 cabin chassis that does not have any backup lights. I remove the tunnel in my sm-465 does have the backup lights installed in the transmission. There is no wiring where it goes, does anybody have any ideas of a wiring harness or how to connect the wiring.

[RustyPile]

Do you have a fuse socket on the fuse box labeled "B/U Lites"?? If so, run a wire from that terminal to a terminal on that switch on the transmission.. From the other terminal, run a wire along the frame to the backup lights.... An 18 or 16 gauge wire is plenty heavy enough to handle the small amperage demand of a couple bulbs..

[david7w5@gmail.com]

Thanks

[RichardJ]

Did your truck come with the sm-465 as original equipment?
If the truck was originally a 3-sp column or an Auto, you may find the wires up by the column where the neutral safety switch/backup light switch would have been.

[david7w5@gmail.com]

Yes. Sm465, I was told the cab and chassis wasn't wired for backup

[Mickeymotormount]

Had a similar issue with my 67 C20. Sold as cab and chassis. SM420 transmission with the reverse light switch, but no wires attached to it. Even the frame harness for the tail lights had only 3 wires, not the typical 4 wires you normally see. The cab however did have all the wires on the inside.

[awryexperiment]

This is something I still need to do. I currently have a toggle under the steering column but need to check the switch in the tranny.

One question: where does the wire from the fuse box to the tranny penetrate the cab? Does it go through a grommet in the firewall or through the tunnel hump?

Thanks!

[RustyPile]

If factory equipped with B/U lights, the wire passes through the grommet with the brake lights and tail lights..

A wiring diagram can be downloaded from the ELECTRICAL forum on this site..