Jaguar Repair: jaguar xs ceased, ford motor company, test light

Question
Hi there,

I have a jaguar xs 2002 and i have been travelling in east africa with it. I hit a hump quite unprepared at a fast speed. After landing back down, the car has ceased and wont start, in addition, the air conditioning and windows wont start/come down respectively. Now due to the general ignorance on cars like this in the area that i'm in id like to be able to at least guide my mechanic...Is this a wiring problem? And what should I definitely be looking at?

Many thanks

Answer
Hi Viv,

Sorry to tell you but I stopped working on any Jaguar after the 1987 models so I have no experience on your car, which is completely different in the electrics as your electrics were designed by Ford Motor company. (an improvement over the original Lucas system)

However, I have studied electronics a little and for any car to loose that many items especially just after a hard bump clearly indicates a connection problem of a major power supply.

Unless you have an experienced Jaguar mechanic he will be hard pressed to come up with a quick fix unless you or he has a wiring diagram of that car. Look through your owners manual to see if Jaguar included one. If not order one from Jaguar right away.

With a wiring diagram most any mechanic who understands electrics can probably trace down the problem.

I found that on any car if you have a wiring disgram you just need to pick one of the several circuits that have failed. I found that usually when you trace that one circuit from "Load" (item that don't operate) and with a 12v test light or a volt meter start checking for power at the "Load" then follow the trail of the wiring diagram one joint at a time and head toward the "Source" (the power supply). With that method when you find the problem of that circuit most likely it will be the cause of all the other failed circuits.

When I had several failed circuits like you do I pick the easiest to trace. This method allowed me to correct most cars very quickly.

Tracing a failed circuit from "Load" to "Source" with a test light and a wiring diagram is a 100% fix rate method. It is impossible to fail to repair a wiring circuit with that method.

Your mechanic does not need to know Jaguar to repair electrics as long as he has a wiring diagram and understands electric.

Even though there are some high tech circuits on the car like the injection system, your problem sounds more like a power supply loss.

Sorry, that is the best I can tell you. Good luck.

Howard