Need help with third brake light install

[tlocus]

I have a third brake light on my trucks cap that I want to use (I hook it up to my trailer harness).

It works but when I use my turn signal on one side it flashes.

When I use the adjacent wire (on trailer harness), the other turn signal makes it flash.

 

Is there a way I can hook it up to remain on when applying brakes and using both turn signals?

 

btw it's a 1991 c1500

 

t

[citydriver]

Welcome to the Forum

 

This may sound like a pain,but you could run a wire right to the brake light switch..

Or you could run a wire to each tailight..BUT you will have to ISOLATE them with a diode on EACH wire so that the turn signals will work properly.

[tlocus]

Thanks for the quick reply citydriver.

 

Will try it out

 

t

[redchev]

You should also look at the wires under your truck. On my 1998 there is a wire just for that purpose in the plastic sheathing where the tail lights plug in to the wires on the frame. I don't remember the color but it was marked for that purpose.