Electrical! Wiring Dash, Radio, Lighter for 71 C10

[BossHoss1]

Howdy,

So I'm embarking on the long put off wiring project for my 71 C10. When I purchased the truck the dash/instrument lights, radio, and cigarette lighter were the only electrical items 'out of order.' Everything else seems to get regular power without any issue.

The Cigarette lighter is disconnected with a hot black wire, that assume feeds the lighter close by. The radio appears to be wired up but in a way I don't understand. I'm attaching a picture of the fuse box to help illustrate my confusion.

The red wire from the "radio" post makes sense but why is another red attached to the 'lights' fuse above the 'cluster' feed? the appear to get spliced together (second photo) and sent to the radio as one wire...

Thanks for any insight...

[markcurry]

....

[ray_mcavoy]

I can definitely see why where that radio wiring would cause some confusion ...

I noticed that the "PNL LTS" fuse is missing from the upper right corner of your fuse box. And it looks like one of those red wires is hooked to the empty fuse clip. I'm guessing the dash lights were not working off their original circuit so the previous owner rigged that mess up to "backfeed" the dash lights off the radio feed wiring.

[BossHoss1]

Thanks Ray. Ok yes, a "backfeed" that would make sense. Could nto figure out why it was wired as such. Going to try and replace the 3A fuse that is pictured above between the fuse box and the radio. Hopefully, when doing so I'll get radio and dash back....

Do I need a fuse for my lighter connection or is that wire always live?

I've got a black 'live' wire under the dash near my lighter; unsure if this was disconnected on purpose or by accident...

[ray_mcavoy]

You're welcome.

The factory lighter wiring used a 12 gauge red wire that plugged into the fuse panel right below the 15A "TRAFFIC HAZ" fuse. It looks like yours has a black wire plugged in there ... does the other end of that trace back to that "live" black wire you found near the lighter? If so, someone probably just wired it up with black (instead of the stock red color) wire.

According to the factory wiring diagrams, it doesn't look like they used an inline fuse for the lighter circuit. And the receptacle it plugs into on the fuse panel is not protected by a fuse either. So the only factory protection would have been in the form of the fusible link out under the hood that protects the main feed wire coming into the cab. Adding an inline fuse to the lighter wire wouldn't be a bad idea though.

[BossHoss1]

What size fuse makes sense if i'm adding an inline to the lighter circuit? 3A ?

Thanks!

[ray_mcavoy]

I believe the lighter circuits in many later model vehicles are on a 20A fuse. So you should be okay with a 20A inline fuse if you wire it up with 12ga wire. A smaller fuse would probably work okay too if you are just using the lighter socket for light loads such as charging a cell phone.