No rear taillights help

[jut]

Hi all new here. Just got a 86’ and the rear taillight harness was missing. I had a harness from a 77 k20 that I thought I would use but the wiring is confusing me. The truck harness has 2 browns, 2 dark greens, 1 lite green and 1 yellow. My question is what’s the extra wires for? If I hook up the one brown and yellow and put the left turn signal on I get side marker and running lights both come on but no flashing. They are also lite very dim. Any help is appreciated. Thanks!

 

[Barrman]

Welcome to the fun. At the top of the page there is a tab labeled "TM". Open that tab then click on the very first thread called "TM's for the CUCV." Then open the one that ends in -20. Appendix F of that manual is a complete very detailed wiring diagram for the entire truck.

The CUCV wiring for the lights is just a little bit different than the civilian because of the black out light system when the years are the same. You taking a glass fuse wiring system and putting it on a blade fuse truck could be part of the problem. That same -20 manual has a great electrical troubleshooting section that will also talk you through everything.

 

[jut]

Welcome to the fun. At the top of the page there is a tab labeled "TM". Open that tab then click on the very first thread called "TM's for the CUCV." Then open the one that ends in -20. Appendix F of that manual is a complete very detailed wiring diagram for the entire truck.

The CUCV wiring for the lights is just a little bit different than the civilian because of the black out light system when the years are the same. You taking a glass fuse wiring system and putting it on a blade fuse truck could be part of the problem. That same -20 manual has a great electrical troubleshooting section that will also talk you through everything.

Welcome to the fun. At the top of the page there is a tab labeled "TM". Open that tab then click on the very first thread called "TM's for the CUCV." Then open the one that ends in -20. Appendix F of that manual is a complete very detailed wiring diagram for the entire truck.

The CUCV wiring for the lights is just a little bit different than the civilian because of the black out light system when the years are the same. You taking a glass fuse wiring system and putting it on a blade fuse truck could be part of the problem. That same -20 manual has a great electrical troubleshooting section that will also talk you through everything.

I see the brown/w and dark green/w are for the black out lights. That’s a start I can eliminate those 2 wires. Thanks for the help

 

[cucvrus]

I probably have a rear pickup harness in my stash of parts. How far away from Fort Indiantown Gap are you? I am in Jonestown exit 90 of I 81. Good Luck. Give me shout back.

 

[jut]

I probably have a rear pickup harness in my stash of parts. How far away from Fort Indiantown Gap are you? I am in Jonestown exit 90 of I 81. Good Luck. Give me shout back.

I am close to Altoona, if I can’t this to work I’ll look you up. Thank you!

 

[nyoffroad]

The dim bulb is probably a bad ground, very common.

 

[jut]

The dim bulb is probably a bad ground, very common.

Bad ground was the culprit! Wire looked intact but hard a break under sheath. Thanks for the help!