I have tried many of the items in the cruise control article here My cruise control light turns on, but it will not set a speed. Having owned other 996s, I know how the CC works.

The only thing I think remains is the 3rd brake light. I bought my 1999 996 with an aftermarket Techart wing. The prior owner did not install the engine fan nor the wiring assembly. Since then, I purchased an engine fan and wiring harness. The wiring harness is ONLY connected to the fan and the fan light. Since I have a fixed rear wing, the harness has the bypass for the spoiler dash light.

-Other posts mention how important it is that the brake lights work. My 3rd brake light is part of the body above the rear wing, and it does not work. I cannot figure out how to get to the light assembly to check on if it is wired.
My engine fan wiring harness has the wire lead to go to the 3rd brake light, but it is not connected to anything (yet).
? How do i get to the brake light, located between the engine cover and the rear window?
? I already checked the fuse, but is there a relay I need to check as well?

 

"..important...that the brake lights work..."

Well no, not exactly.

What is important, with regards to CC operation, is that all three brake bilb circuits represent a low resistance when the brake lights are off. My '01 has a 50 watt halogen bulb that is only in the high mount brake light circuit when the brake lights are off. Apply 12 volts to the high mount circuit and that picks up a relay that switches the LED high mount "bulb" into the circuit.

 

[QUOTE=wwest;9633304 My '01 has a 50 watt halogen bulb that is only in the high mount brake light circuit when the brake lights are off. Apply 12 volts to the high mount circuit and that picks up a relay that switches the LED high mount "bulb" into the circuit.[/QUOTE]

Thanks wwest. two noob questions.
?How did you get to the high mount circuit? (no room from the engine bay)
? Are you saying that you installed a 50w bulb on circuit in addition to the led high mount 3rd brake light to make it work?

 

I removed the high mount light assembly and installed the minature relay and 50W halogen in the wiring harness and slid "all" back behind the assembly. Relay NC, Normally closed contacts "power" the halogen, NO the LED HM.

 

I would love it if someone could point me in the direction of a video or a diagram to show me how and where to install the relay and bulb for my LED light.

Any help? Please.

Thank you.

 

My cruise control light would turn off as soon as I pulled out of my driveway. The issue seemed to be tied to LED after market brake lights. I was able to install a relay which went inline from the brake light socket to the brake light bulb.
Seems to be working well now. Purchased on Amazon.