Uploaded some pics of some plugs that are unused behind the dash. Been curious of what they were intended for. Any thoughts?

Anyone?

No one?

.

Only clue i could give is grab a wiring diagram from the FSM and layout of looms and plugs are shown. Might help.

Ive combed through the 1999 wiring maps and have not had any luck on finding anything for these 4 large connectors. What else could you add to these trucks that those would be used for?

Your going to need a FSM book it will show the plug and pin out.

Pretty sure that white one the trailer brake harness for brake controler. If you have brake controler hooked up then im wrong lol

Stanley we need some pics of your rig the built not bought bed and bumper is interesting me. And that youve turned it in sw truck.

Thats awesome, not many know u can put single wheels on.

Edited Sunday at 02:57 AM4 days by Evan

Here are some older pics. I built this truck and redone so much, and its sad to say but shes in pieces now but alot of her parts still live on in the 1500 cummins.

Im gonna try and do some video updates/progress on the 1/2 cummins should anyone be interested. She's gonna be sweet!

Ohhh man that is super sad shes in peices. You did awesome on the bed and bumper.

Thank you for shareing photos

Thank you! The bed still had some things to get done on it, but mostly done lol. Now hopefully someone will buy the rolling cab/frame with it...

On 10/30/2026 at 8:17 PM, Stanley said:

any luck on finding anything for these 4 large connectors

I went through the FSM section 8W-80 CONNECTOR PIN-OUTS and came up with a few ideas. Does this truck have the "high-line" option, seat heaters upgraded factory radio?

That was one thought of the plug in my mind but never really seen a high line truck with the options under the dash. 🙄

6 hours ago, IBMobile said:

I went through the FSM section 8W-80 CONNECTOR PIN-OUTS and came up with a few ideas. Does this truck have the "high-line" option, seat heaters upgraded factory radio?

It has the highline CTM assembly. But that's all I've found under the dash. I wish I could add heated seats, electric seats, and I'd love factory keyless entry!

*Edit: scratch love to have - been reading aftermarket with remote start, alarm, keyless entry is way cheaper and more reliable...?

But unfortunately it does not have seat heater, upgraded radio, electric seats...

Edited Tuesday at 04:07 AM2 days by Stanley

1 hour ago, Stanley said:

*Edit: scratch love to have - been reading aftermarket with remote start, alarm, keyless entry is way cheaper and more reliable...?

But unfortunately it does not have seat heater, upgraded radio, electric seats...

Truth. But I think we can do better with aftermarket at this point than trying to get the highline option working correctly. I could do a car alarm better than a high line security. 🤣😂

It would be easier to find Jimmy Hoffa than parts for an old HI Line system in these trucks. Good quality aftermarket accessories is the way to go.

Ill be honest, I had to Google Jimmy Hoffa 🤣

It would have been cool to have all of it already, but I can safely assert my new opinion that aftermarket is the way to go!