Okay.Okay. I have given up. The problem is brake lights and park lock. The vehicle is a Disco 2 2004. Background.:

The vehicle was hit in the rear and the tail door replaced. The door frame was a little out of line on the bottom so the door didn't close. I brought the car to a shop and they "stretched" the floor to fix the door closure problem.

An early 2002? bumper was fitted. With it's lights. I had replaced 2002 lights on the body that had replaced the standard 2004 lights. Up until the replacement bumper was put on, all the directional signals and brake lights worked.
Driving home with the door aligned and bumper on, the directional signals flashed slower. The brake lights failed. the park lockout still worked.

I figured somehow the wires had gotten crossed somewhere and there was a short. I replaced the "bumper" lights with the appropriate 2004 units. The car now has all year appropriate lights

No luck on the brake lights. The first item I checked was the brake pedal switch. Working normally, but I ordered a replacement and swapped it out. Still no brake lights.

Somewhere in my zeal to accomplish too many tasks at once. I used the opportunity of having the brake light switch accessible, to splice a wire into it's 3 wire harness to connect to a trailer brake controller. (just solder spliced in this take-off wire, too the middle wire of the harness. Not connected to anything yet. A 12 volt test light on the tap wire to ground showed it operated when the brake pedal was depressed. This confirmed the electrical supply to and thru the Brake switch.

Satisfied I was on the right track I next went to the trailer harness socket behind the right tail light. I looked at the odd ball connector and figured I'd "improve" the system to wire in a 7 pin trailer socket on the bumper. I had checked that the left and right lights are controlled by different relays for the turn signals, and I knew I needed an electronic "moderator" to "dumb down" all the Disco light paths to a suitable output for the trailer lighting. (And for isolation to prevent the trailer light load from affecting the disco 2 computer.)

Sooooooo, I cut off the trailer harness plug behind the right tail light. My plan was to isolate all the circuits to a EURO Style screw terminal barrier strip. I could solder splice my trailer light "controller - moderator" - to the car harness and then the wires from the moderator controller into the new barrier strip. Then wire the 7 pin socket to the pass thru terminals on the barrier strip. Well I got as far as cutting the connector off the car harness. Went to look for the "Euro barrier" strip in the garage, and other duties interveened.

When I got back to the project a month later, I started the car to move it and though it started I couldn't shift it out of park. I went back and reviewed the electrical schematics and I couldn't see any "cross connection" in the trailer body harness that would send power to the park lock out solenoid in the console.

I was very disheartened, and of course, winter arrived. At 70 years old, working in the cold is impossible for me, and at 6'3" getting under the dashboard is impossible without removing the drivers seat. In preparation for Spring, I am posting this plea for any advice or insight from those of you who might have faced a similar problem. I've used the winter to print out connector diagrams, I purchased a used interior fuse box with the "intelligent" system relays, and found my EURO barrier strips. I'm getting ready to tackle the job again, but I hoped a little extra knowledge from the "bruised knuckle crew" would make my efforts more effective.

Thanks for any insights,

Tom

 

Park issue sounds like the XYZ switch on top of the trans. Did your reverse lights work before you had the shifting issue?

Check your brake light wiring for damage or a short to ground where they pass through the body behind the tail light. If it was hit, it could have caused wires to get cut there. That would cause lights not to come on.

When you step on the brake pedal to shift from park, do you hear a click coming from the transmission? If not, check the operation of the XYZ switch on the trans. They have common problem of ****ting the bed without warning. They're in a bad location which sees a lot of moisture.

That's where I'd start.

 

Just wondering, were you able to test during the entire process of replacing and rewiring the system? Also during that process, were you able to shift out of park? Was the initial wiring project finished before you stopped for a month?

 

Medical problems interrupted project, Then working on summer house for 6 months, got back and it was too cold for outdoor work.

Park interlock had worked before I cut the factory harness end off the trailer connector. (Battery out). I guessed that the installation of the earlier year bumper and lights by body people may have blown something in the electrical system disabling the brake lights. The 2002 light assemblies on the rear body I had changed to the 2004 lights before going to the shop. It was driving home when my follow driver noted the signals erratic and no brake lights. It was after this that I replaced the bumper lamp assemblies to the 2004 units, and replaced the brake light switch. I had started working on the trailer harness, figuring I'd find and correct any problems in the circuitry while installing the trailer kit. Of course I hadn't counted on the involvement of a whole ton of logic circuits under the dash for the brake circuit. The vehicle starts fine. Will not shift out of park because of solenoid not releasing the selector.

Using the schematics in the manual is very difficult (for me) as the various devices and locations, pin outs etc. are illogical to my mind. I'm used to complete circuits and the manual seems to jump from section to section. I guess I'll have to get used to that to fix this. I plan to "cut & paste" a brake circuit, turn signal schematic that is a full flow chart, but I am so frustrated with my own limitations (age related) that this is turning into a very unpalatable chore.

In the mid 1960's I started my job cycle as an installer of car audio systems, then worked as a broadcast engineer, and built quite a fair share of Heathkit devices for hobby use. I've worked on all my own cars for years, and from tailpipes to timing chains, gapping piston rings to plasti-gage the bearings, I've dabbled in quite a few things. I've even had some experience with LUCAS on my Sunbeam Tigers. I am frustrated that I can't "put a finger" right on the trouble and correct it. I was hoping that in the knowledge base here, I could pick up some failure knowledge that would lead me to a likely fault. This isn't my daily driver, so I have time to work on it, but I haven't been continually working on cars for the past 50 years for a livelihood. I've skipped a lot of model years and changes, and this introduction to so many interrelated complex systems, and my own unfamiliarity with the purposes of those systems is raising my level of frustration.

I will check the xyz switch first chance I get. I plan to disconnect the harness to the lockout solenoid and apply 12v direct to see if it failed. If it functions from alternate power, I will run a ground and hot to an external battery like a lantern battery and just apply power to the solenoid to get it out of park. I can disconnect that power once the shifter is free. hook it up again when I need to free the gear selectorfrom the park position. If there is no power to the solenoid, well that's another chase to pursue!

Thanks,
Tom