Series III XJ6 a/c amp questions

[wkilleffer]

Hello everyone,
I'm getting a bit fed up with my Jag's a/c. Just about the time the interior gets comfortably cool, the system switches the heat on full blast. It will respond to the temp setting knob, but not for awhile after it's played that trick.

According to the jag-lovers.com site, that's a symptom of a/c amp failure. The a/c amp's an expensive part, though they seem to think that an aftermarket unit can be obtained for around $150US. I've asked about it on their forum, but am impatient enough to ask here as well. Where can I get an inexpensive new or rebuilt aftermarket unit?

Also, there's supposed to be a way to bypass the amp entirely that requires some cutting into the system wiring. I'm not against the idea, but don't want to ruin things either. Since I'm trying to sell the car, it's probably best that everything work as intended.

Another question: I've heard that changing the amp can affect certain a/c functions, such as being able to swich the system from Auto to High or Low and actually have something happen. It used to, but doesn't anymore. The switching the heat on at bad moments hasn't always been a problem either. I've owned the car for about a year-and-a-half, and this has been trouble for about a year.

Any advice or suggestions would be appreciated.
Thank you,

 

[John S Farrington]

I would not try to modify the system; that is a very bad idea particularly if your system is partially functional. Either your amplifier or the mechanical servo that it drives is causing this problem. The amp is probably the problem as it sounds like it is breaking down after it warms up. If you can get a rebuilt amp for $150 that is a good buy. They usually cost double that and as the car gets older they are getting harder to find.