Does anyone have any suggestions as to what could be the cause of my car problem and how to fix it? I live in Southern California and have a 2001 XJ8. A couple of days ago the check engine light went on for a short period of time and then went off. Car appeared to be running fine. Two days later I tried to start car and it was totally dead. No electrical at all. I thought it might be a loose wire or short because I had experienced this before and then after leaving car overnight the car started up. I jiggled some of the wires under the hood, nothing happened. Let it sit a couple of days and used a different vehicle. Then tried again, nothing. Went to trunk and checked battery cables - all looked fine. Opened fuse box in trunk and pushed on the fuses - they appered to have popped up a little and when I pushed on them they snapped back into place. Opened car door and overhead light went on. Turned key, car started right up. But all of the warning lights on the instrument panel were on, gas gauge kept moving up and down, and warning messages kept flashing. I tried to put car into reverse, but could shift out of park. So I turned off car and used key to manually switch gears into neutral, then started car and was able to drive it. While driving I found that speedometer does not work, neither does the temperature gauge.
I'm assuming that the lock out switch at the brake pedal is not working properly, and that's why I can't move the gears out of park.
The mechanic I took it to says he feels that I need to replace the instrument cluster (new one installed will cost $1200). Does the instrument cluster have anything to do with the brake pedal lock out switch? Or is it a computer issue that is impacting the instrument cluster and the lock out switch? Could it be a bad wire? Any suggestions?

 

The diagnosis you've received could be correct as the mechanic that looked at it had the luxury of seeing the car. BUT, if you're questioning the diagnosis, there are two things to check that are simple.

First, look up the earth links (grounding points) on your MY car. They are available on this site by opening up the JTIS electrical guide, find a page there with a diagram of the car showing all the grounding points. Locate each one and check it for good ground.

Second, the battery needs to be consistently about 12.1v. Once the battery routinely drops below 12.1 weird electrical "things" begin to happen. They get even worse if the batt falls to 11.1; 11.2.

 

Here's a link to the wiring diagrams for your car - so you don't have to deal with JTIS for them.

http://www.captainjaguarscathouse.co...ec%20Guide.pdf

 

There was a service action S484 a long time ago for this fault (413-S484).
There is a specific VIN range of back plates on the INSTPK that were faulty and crushed a solder joint causing the exact fault you have.
You might try to scrape the spreading solder to repair the circuit but sometimes the damage is done and a new inst cluster is required.

I'll attach the service action TSB for reference.

bob gauff

 

Thanks stevetech, QuadManiac and motorcarman for your responses. I'll follow up with my mechanic.