I am unable to get great pictures of the modified harness at this time. I live in a high rise downtown and the association is very strict about anyone doing any work on their car in the garage (big pain). However, the picture below is as much as of the harness I could pull out without breaking out the toolbox. Generally, everything you see pictured is hidden within the lid for a much cleaner look.

*Disclaimer*The following process is based from memory of a quick fix I did several months ago, so please be kind as it may not be 100%

With the decklid open, you will see the harness traveling up the passenger (right) side of the lid, underneath the assembly plate. Unplug the bay light and fan. Remove the hex bolts securing the assembly plate inside the decklid. I believe there are 9. Remove the assembly plate. This will expose (among other things depending on the model of your spoiler) the harness. You will recognize the bay light plug, the fan plug. And third brake light plug. You will also see two other wires with switches at the end. I installed a cheap wiretap (I believe they came from Autozone) on each side of the switch and installed a jumper between them. That’s it. When reinstalling the harness and assembly plate, be sure to take notice of the location of ALL of the wires on the harness. It is easy for excess to get very close to the cooling fan.

I plan on going to a friend’s garage at some point soon to troubleshoot my PCM 2.1. If someone would like, I could use the time recreate the process and take pictures to document.

 

Thanks a ton! I'll have to do this tomorrow at my friends garage, I don't have a hex bolt that size.

+Rep.

 

Wow just dug this thread up.

This seems very useful. Has anyone else done this by bypassing the switch and not having to invest in the $70 harness?

 

I just bought a 2005 C2S and have not added my new wing. Yet I have that annoying warning light and 'I' (red) on my dash. When changing the oil I had my buddy hit the brakes and wow no upper or wing third brake light. Open lid and pressed on wiring harness on passenger side forward of brake lens. Closed the lid - and bam both third brake lights worked. Wing down the one below window worked...wing up only the one on wing worked. All fixed, right.

Drove it 10 miles and BAM the annoying light back on. Get home wiggle wire again and lights work. Now here's the rub...the same harness powers the turn signals, R/L brake lights, cooling fan, wing motor, etc. I thought connector would be bad all these would be going out.

What the heck? Has anyone else had this issue?

 

Looks great! One of the best I have seen.