Instrument light accessory plug

Reply Subscribe

Thread Tools

Search this Thread

Oct 4, 2017 | 04:32 PM

ddepumpo

Thread Starter

Cross-Country

Joined: Jun 2017

Posts: 82

Likes: 1

Instrument light accessory plug

The truck is a 1974 F100 short bed, manual trans, original motor was a 302.

Does anyone know where the accessory plug C-789 (it might be C-709) can be found behind the instrument cluster? See page 5 of the wiring diagram (at grid E-50) below. In the notes, it is described as “behind instrument cluster for customer usage”. I can’t find it under the dash. It is supposed to be BL-R wires, so I assume it is connected to the dash lights. If so, I would like to use it for my tach light.

FWIW, I did find the yellow plug under the dash, and am using that as a switched power source for the tach. (I learned about this on the forum….thanks.) I currently have the tach light tapped into the fuse block, but it would be nice to find the accessory plug.

Attached Images

Oct 9, 2017 | 09:12 PM

ddepumpo

Thread Starter

Cross-Country

Joined: Jun 2017

Posts: 82

Likes: 1

Anyone, anyone, Buehler ... just kidding. Has anyone else found this plug for accessory dash lights? Thanks.

Oct 9, 2017 | 09:33 PM

meangreen92

Logistics Pro

Joined: Jul 2005

Posts: 4,217

Likes: 154

Look for a light blue wire with a red stripe. There is for sure a place to plug in with a male spade terminal, at the radio connector. It's a two-wire connector with a yellow wire for switched power, and the blue/red wire for the radio dial light.

Oct 10, 2017 | 03:52 PM

ddepumpo

Thread Starter

Cross-Country

Joined: Jun 2017

Posts: 82

Likes: 1

Thanks meangreen. I'll check it out.

Oct 10, 2017 | 05:10 PM

meangreen92

Logistics Pro

Joined: Jul 2005

Posts: 4,217

Likes: 154

Oh wait, the three wire one is probably going to be up around behind your light and wiper switches. It's yellow on my truck. Sorry, kinda misread the OP...