Okay guys....for those of you having the same problem as I had in my 98 XJ8, both rear brake lights wouldn't work due to faulty SCLM. I read several posts and none were detailed enough to figure out what was going on. First, unhook the high mount stop lamp and lay it on the parcel shelf so you can see the wires coming out of the end. Notice the wire with the stripe in it. Go to your trunk, pull the carpet sides and fuel tank carpet. There is a plug up under the deck shelf that has wires going from it. These are the wires we are looking at. Unplug the harness, its easy. Locate the same color wire that is coming out of the high mount light. It's the striped one, other is ground. Cut that wire, but leave enough so you have room to wire it back. You will then pull your driver side brake fixture out unhook that harness and cut the brake lead wire, which should be second one in from right of the harness. Before anyone does this I'll double check and take photos so that I can send you so you know which ones and won't be confused as I was and spend 2 weeks or more asking what to do on here. You will strip both ends of these wires and hook a bypas or jumper wire there. You should twist all 3 ends together and wire cap or use electrical tape to cover them. Run your jumper wire along the original wiring harness up and around past the fuel tank to the wire that we cut at the wiring harness plug. You will strip both ends of that wire and again wire all 3 ends together and tape or wire cap off. Plug your harness in and your brake light plug in. You won't have to jump the other side because the harness doubles back to passenger side anyway and its already going t get power from one side. Now you will have working brake lights without the hassle of going and unlooking the slcm and all that. Anyone that wants to see pictures let me know and I'll take them so you see exactly what wires.

 

Many thanks for the knowledge on this forum. Using the info found here this newbie was able to bypass the SLCM and get my brake lights working via wiring to the HMSL. However, I need to find a way to get a wire from the boot past the bulkhead so that it can connect to the HMSL (without running a wire out the window). I don't want to start drilling without direction - Suggestions ?

 

I cut rear brake light wire from SLCM and connected it to the trailer brake wire that is in that trailer connector right next to SLCM. No need to run any long wires.

 

Where are both wires? Is there pics or a diagram ?

 

Sure, here:
https://www.jaguarforums.com/forum/x...roblem-120667/