Electrical problems – again

[james s]

I have been having electrical problems for about 18 months with my 98 xj8

About that time the windscreen wiper motor started to behave erratically – doing random sweeps of the screen when off, and then moving jerkily across when on. Only about 1% of the time.

Occasionally the gearbox won’t come out of park – it seems the switch which links it to the brake isn’t communicating properly. Even less frequently the car wont start and the alarm fob ceases to work, and on occasion the interior lights stay on when I lock the car.

Over time I have come to think they are linked, particularly the box and starting problems only seem to happen when the wiper problem has been particularly bad.

In Jan 2006 a well known specialist near Gerard’s Cross had it for a almost 2 weeks and though they had got to the bottom of it when they replaced the fuse box. It did seem OK for several months (with the exception of the wiper problem) but over the last week the gearbox problem has come in a bit more frequently.

The only other info to pass on is that the gearbox was replaced a few months ago It was initially rebuilt, but the change down was very rough and after a while it was replaced. The new one is generally fine, but occasionally seems to stick in too low or high a gear when the box is in ‘normal’ mode. Seems fine in sport however.

Has anyone experienced anything like this. Jaguar diagnostics can’t pick up anything

Thanks

James

[james s]

Still having problems

Can anyone suggest a Jag specialist in the South East with the necesary skill and tenacity to get to the bottom of this

Thanks

[kinjachris]

Check out this video on YouTube. You aren't the only one...

www.youtube.com/watch?v=YAibNrzcigs

[blueflash]

Sounds like a common earth problem to me. Though jag gearboxs are linked to lots of things, i had one tripping out and going into limp home mode (stays in 3rd gear!),had it checked over - oil & filters changed in the box. Ended up being a dirty connection to the throttle. Jag electrics are very sensative could just be a dirty earth connector, give all multi-plugs agood dose of WD40 and work them in n out afew times! Hope it helps.

[Tame Technician]

If your willing to spend a but of money on parts you might want to try the following.

For your wiper fault, it is either the internal switch within the motor that makes the wiper park in the right place, or the two water proof relays under the bonnet that control the wipers park and speed.

When it doesn't start and the remote is inop, is the battery flat? could be way down on volts if the interior lights stayed on all night. Interior lights staying on could simply be a sticking door micro swithc, car thinks door still open and keeps lights on. When it does it and you lock the car do you get a different indicator flash than normal or an error bleep? Could also be the BPM Body Processors Module, they can have bad earth internally. This could effect getting stuck in park, but that is far more likely to be a brake pedal switch issue.

The relays and the brake pedal switch are cheap, but the wiper motor and the BPM are pricey. I would change the wiper relays and the brake pedal switch and see how you go.

[groomi]

I'm experiencing the wiper problem which is infuriating. I have heard though, that it can be caused by incurrect current from the battery. This would seem possible with mine as it only started after I had to replace my battery in a hurry with a Halfrauds one, which despite being the right one in their catalogue, is half the size of the original battery.

Haven't got round to replacing it yet, but hoping it will solve the problem.

[Tame Technician]

Wiper motor only pulls like 10amps max, cheapest smallest nisan micra battery gives 240amps. Dont beleive a word of it, sorry.

Don't waste your money on another battery, change the wiper relay. Or have a good tech test the motor, one of the wires should give an earth as it reaches the park position, if the BPM doesn't see that earth the wiper keeps going.