Hello all. I know its been asked before, somewhat, but I just purchased a used truck cap and I'm trying to find the best way to wire the third brake light. I thought about right to the drivers side but don't want corrosion in the future, I thought about the 4-pin and 7-pin connectors, but it would make the brake light blink if I had a turn signal on while holding down the brake. What would be the best way to go about this?
Thanks!

 

Mine had a 4 pin connector and it did not blink.

 

Hmmm I heard that was a problem. Did you just wire the cap tail light to the right side (or left side) brake light. I figured they would also be used as blinkers. If that's the case I returned the 4 pin already and got the 7-pin connector but has the same connections. But if I hook it up to a tail light it shouldnt blink? And out of curiosity, does our truck have that lone wire underneath (chmbl) for this purpose?

 

I don't know. The cap already had the connector on it, I just pluigged it in.

 

There is a special wire already under your truck that is tied to the Center High Mount Stop/Brake Light. Mine was taped up under the bed near the bumper. This is the proper wire to tap for power for your truck cap.

 

Thank you! I went under there at lunch and found it. I knew there had to be something.

 

Be careful. My cap has a high mount tail and backup light. I don't know what the previous owner did, but it killed the circuit for the backup lights in the PCM.

 

I just rewired mine to install a flasher for the shell. Originally, I wired up a 3 pin towing harness into my towing harness so I could connect/ disconnect any time I needed. I was able to harness power for the brake light, which was always on w/ my running lights than got brighter when I applied the brakes as well as a separate power for my light inside the shell. I bought a new led brake light for my shell and a flasher, so I had to rewire it so it only came on when I applied the brakes. I haven't had any problems with my PCM. I also have 2 additional LED lights tied into my reverse lights.


Wish I would of know this... probably would of made my wiring a lot nicer and easier.

 

you wouldn't happen to have a picture of this, would you? I looked under mine and I can't see anything resembling what you described.

 

Pictures are in this thread ----> Here.