I know there have been several write ups on this. I finally gave up on the garbage pressure switches. 1st one lasted ~6mo, 2nd one last about 18mo (surprisingly), the 3rd one lasted ~2 days. Total garbage.
This is a rev0 configuration that works for now. The switch came from Welsh. The bracket it came with was too short for my configuration so I made another one, about 1/2 in longer. Here is the Jerry Rig bit; I routed the wires throught the bulk head using the 2 of the 3 existing holes for the carpet pad under the pedals, then ran them to the wires at the old switch. So for now I have one screw holding the carpet and the left side tucked away. Works for now. I did not want to drill a hole in the bulkhead. I know JM had a write up on wiring it under the dash which is much cleaner. Installation was easy. Below is a pic. What you are looking at is unrestored original carpet.
It is the way to go. More than once I had folks tell me on the road that my brake lights weren’t illuminating. The best one I tried was a VW pressure switch but even that one would only come on when I stopped on the pedal rather than lightly applied it.
FYI, no kit is necessary for this. There are some old posts about this that described a common Volvo mechanical switch. It was less than $10 on Amazon and it has a decent amount of threading for adjustment. It took 30 minutes or so to fabricate a bracket out of some strap steel. Also no reason to wire it all the way out to the engine bay. There is a multiway connector for the lights in the left corner of the dash so I was able to run wires behind the trim panels just a few feet from the switch. Between that and the LED taillight kit from XKs I have a lot more confidence that people will see me stopping.
