I have an intermitant fault with C/C. Sometimes the fail safe message appears and the C/C won't work. I took the pedal switch off and it seems OK, no burning on the PCB. Any other sugestions?

 

I assume you have a XJ8, but the year is important with cc problems. It would also be of use if you would have the stored codes read and list them here.

 

Yes it is an XJ8 3.2 2001 with 70000 on the odo. The only fault code coming up is P1647, hot sensor, which I'll change when the frail looking LHS Cat eventually fails. The reason l believe it is the C/C is that the light on the J gate doesn't light up when C/C is selected and the fail safe mode appears. Seems that when the ignition is turned off then turned on again as it if it is reset or rebooted it works again, or until it croaks again.

 

One of the micro switches in the brake switch may be intermittent/failing, or the plug needs cleaning.

The following is what I learned from the XK8, and I suspect the XJ8 is the same:

I know it's inconvenient to access the plug, but not as bad as the switch. When the problem occurs, try checking the pins with a multimeter. The outer pins are one circuit, inner the other. Pushing the pedal opens one set, closes the other.

 

Yeah I think this is the way to go. As you say it is a tad awkward, but hey, I'll buy a reversible ratchet wrench which will make it easier. Thanks a lot RJ237.

 

Hi Kjallak,

If you need one ratcheting box-end wrench/ring spanner, I'd recommend buying a full set. They're a lot more expensive to buy individually, and once you have one, you'll wish you had all the sizes. Here in the U.S., Sears currently has an individual 17mm GearWrench on sale for $15.00, but a set of 8 wrenches (sizes 8mm to 18mm) is on sale for just $40.00. I honestly don't know how I ever lived without them.

Cheers,

Don

 

+1 - it is the brake switch

 

Just called at Homebase, UK equivalent of US Homedepot, and got an 8mm flexi/combi ratchet for £4.50 made by TorQ. Fortunately Jag used a 7mm bolt and an 8mm nut for mounting the switch so a regular combi will for the nut, however it'll also come in handy for removing the air filter and such like so money well spent.
I've got a replacement switch coming tomorrow, funny thing is the fault didn't come up during trip to and from the store but I'm damn sure it will just when I need the C/C most...

Thanks Don

Kjallak