S3 no power to AC clutch
 

Hello

My '85 XJ6 has no power to the AC clutch.

The fuse in the passenger knee-panel is good, and a test lamp shows power going through the fuse holder.

Is there another fuse?

If I run a wire from the battery to the thermal fuse at the pump, it runs.

Thanks,

Rob

The system has 4 fuses.

- on the ground wire for the amplifier
- behind RH knee panel, as you mention
- #16 in the RH fuse panel
- #6 in the LH fuse panel

Cheers
DD

Just a minor clarification

In about 1983 Jag changed the #6 fuse location for the AC to #13. So if your car is pre-83 you'll find the #6 fuse under the scuttle on the drivers side and the big 50A fuse (#16) on the passenger side.

'83 on they are both on the passenger side, but somewhat inconveniently, Jaguar failed to number them. #16 is the big 50A fuse and just count back to find #13, then dig out your Sharpie and mark them!

Rob, I think there's a non-adjustable Ranco switch in there somewher?. If it fails (e.g. think's the evap is too cold) you'd have this symptom.

Also, there's some Leatherique expertise wanted in another recent thread on this site.

Exactly.

The "Ranco Thermostat" is behind the console RH cheek panel, roughly rectangular, brown and/or brown/yellow wires. For testing it would be simple matter to bypass it by jumping the terminals

Cheers
DD

There is an INLINE fuse (usually called fuse 67) on the RIGHT side of the climate control box above the mechanical servo unit.

bob

Thank you all for responding.

I'm sorry for the delay. Retirement has slowed me down.

I checked everything above, and it all checks out fine. I learned a lot too.

So, with all fuses and Rancor checked, I had another look at wiring, and found what I though was the problem; one of the 3 wires coming off the thermal fuse was not connected to the back of the compressor. See pic.

But, the slim straight pin connector on the compressor was capped with a plug. ??? There was no where to connect it, unless I removed the cap. I checked a couple of parts cars I have and all were connected at the back of the compressor. ???

My car is 1985; was there a change, or any reason the connection was capped?

Thanks,

Rob
https://cimg0.ibsrv.net/gimg/www.jag...2d9f9938b4.jpg
https://cimg1.ibsrv.net/gimg/www.jag...3e099c7ffa.jpg

The 'cap' is the plug that all compressors come with....at least all the ones I've installed. My guess is that the compressor has been replaced and the installer forgot to swap the superheat switch onto the new compressor

However, lack of that switch shouldn't prevent the compressor from engaging

Cheers
DD