Could be massive coincidence but I had AC compressor changed today and now every time I go over 15mph the ABS light comes on and stays on.
is there anything that could be disturbed in area of compressor or right hand wing that would upset ABS ?

 

There shouldn't be anything there close. Since it doesn't come on until the car is in motion I would check the wheel speed sensors.

 

I just think too much coincidence for ABS to go wobbly immediately after AC compressor change.
I spoke to engineer and he replaced a fuse in the R/H wing to get compressor to work and did a fair amount of fighting underneath to remove old compressor.
Is there anything around there that could be disturbed ?

 

Maybe the wiring to the r/f wheel speed sensor but it's not really close to the compressor. You can check the sensors with a volt meter if you don't have access to a scanner.

 

The abs compares wheel speeds continuously, and if it finds them to be out of kilter without the brakes applied or steering turned, assumes a problem and illuminates the light. Some leeway is allowed, so doesnt happen at speeds below 15mph or so.
The symptoms you describe sound very like a wheel speed sensor has been disconnected or its wiring damaged, as has already been suggested. Stranger things have happened when there have been wrestling matches to remove components. Try a code read, as it should tell you which sensor is at fault, if your reader can access abs codes.
Another possibility is dirt/corrosion build up on the reluctor ring. I have had this on other older cars if they have been idle for a while, although not on the Jag funnily enough. Either way, shouldnt be a huge drama, as front sensors arent so hard to replace.

 

Good news, I fixed it ! Basically left car alone all day and she seems to have word with herself and light has gone out.
Bad news reversed into a wall and bent exhaust, grrr

 

The service tech might have had to jumper a wire connector (the low pressure cut-off switch) near the abs module in order to engage the new compressor. Check those wire connectors in that area to make sure they are seated properly.

Its possible that a minor disturbance of the abs module could trigger the intermittent loose connection inside the module that would set the abs light. Many have seen that problem and it can be corrected by resoldering, if your abs light continues without any other obvious cause.

My new Foxwell code reader still will not read abs or airbag codes in my car. I think the x300 software is too arcane and those functions are not compatible with modern scan tools.

 

I think I have worked out what’s going on. Fuse 8 had been pulled from R/H wing. This does AC comp and alarm sounder.
Since fuse was replaced I had ABS light problem and tonight flat battery.
I think fuse was pulled as alarm internal battery was killing car battery? Low voltage put ABS light on.
Does this sound possible, if so can I just unplug Alarm battery or something as I want A/C but don’t want alarm ?

 

Turned out my car battery was week and alarm sounder charging its internal battery was enough to finish off car battery. Alarm sounder unplugged and new battery fitted. Problem solved