About a month ago I bought a 1987 Jaguar XJS in rough condition with the goal of restoring it. I was able to get the engine to start initially, but I ran into electrical issues after working in the center console.

While I had the center console apart, I disconnected some ground wires (mounted to the shifter bracket area). I then mistakenly cranked the engine with those grounds disconnected. At that moment, I saw smoke coming from the center console wiring, specifically it was coming from the Auto Gearbox Wiring Harness.

I immediately stopped, reconnected the grounds, and tried again — but the problem persists:

• With ignition ON (engine not cranking): everything appears normal, no heat or smoke
  
• When turning the key:
  • Starter clicks repeatedly (no proper crank)
    
  • Wires in the center console begin to smoke (Auto Gearbox Wiring Harness)
    

My current understanding is that during cranking (high current draw), power is somehow being routed through smaller console wiring instead of the proper path.

I’ve included a Google Drive link to images of the center console wiring and a video of the issue during cranking. I’m looking for advice on the most effective and safe way to track down the fault. Any guidance would be appreciated.







https://drive.google.com/drive/folde...OJ?usp=sharing

 

Here goes.

1) Welcome to the Forums, do your thing in the New Members Area when you can.

2) Being an 87, I will ASSUME a V12. If so you got a TH400 slushamatic transmission, NO electrickery involved.

3) Take good hard look at the engine earth strap fiasco at the LH engine mount, and its brackets. OE is engine to cradle, cradle to chassis, and the OE straps are garbage it best.
That Earth misiing is as common a cold beer in any pub. The system has NO idea, so looks for any earth path it can find, oops. Gear Select cable and accelerator cable are #1 in its sights, and these 2 will smoke like a train when cranking the beast. That starter motir is HIGH Amp sucker.

I will ask Norri to move this to the XJS section, where it belongs.

Fill in the blanks on the car when you can, as it does matter a whole lot.

 

There are two micro switches at the front of the gear selector. One of these controls the power from the starter to the starter switch to the solenoid. If you have that disconnected or wrongly connected, this would cause a short = smoke AND cause the starter not to work.
You need to find the starter circuit diagram for your model and country version, and check through it.