A/C Clutch not Engaging

[jimmyt]

OK folks, I can see that this topic has been touched on before but the threads have not solved my issue. The scenario is thus:

1993 80 Series Land Cruiser:

A/C Magnetic Clutch is not engaging when A/C button pressed. Cannot find Magnetic Clutch Relay.

The Magnetic Coil has been replaced and works when hard wired to 12v, the system has refrigerant (checked by garage) and functions when hard wired. At this time there was power at the magnetic clutch +ve wire but not now for some reason.

There is power at the A/C fuse on drivers side. The A/C CUT RELAY (water temp) functions (shown in picture) and I have tried another A/C Amplifier however I cannot locate the A/C Magnetic Clutch Relay. Does anyone know where the little bugger is?

I have not checked the Pressure Switch yet.

James

 

[Dave]

Check you got continuity across the low pressure side of the switch first.

 

[jimmyt]

Will do, just found another circuit diagram. It is possible my HZJ80 does not have a relay for Magnetic Clutch - just runs through A/?C CUT RELAY controlled by water temp sw. Will check for continuity here too. Possible corroded wire.
Cheers.
James

 

[frank rabbets]

Short circuit the pressure switch. If the A/C cuts in it's a low pressure in the system. DO NOT RUN LIKE THIS AS YOU WILL SEIZE THE PUMP. This is just a diagnostic check.

 

[jimmyt]

So I think this is the circuit for my HZJ80 which does not show a Relay for the Magnetic Clutch. It shows the A/C Water Switch charges the A/C CUT Relay (normally closed), I assume to CUt Out the A/C when the engine is running hot and thus help with engine cooling, however I cannot locate the said A/C Water SW.

When I remove the A/C CUT Relay and bridge the terminals 3 & 4 the Magnetic Clutch functions leading me to the A/C Water SW being ON. Any ideas of the A/C Water SW location? I tried to locate using wire colour in the engine bay but with little sucess. The Circuit location in the manual is not very helpful.

 

[jimmyt]

So just to close this one off. The offending part was the A/C CUT Water SW. These are about $150 from OEM and not much less for aftermarket ones, I have disconnected so the A/C works and will wait to get a second hand one.

 

[Noel]

Did you find / locate the Magnetic Clutch Relay on the vehicle?

 

[Dave2000]

Car not with me at the moment but, did I see a label on the under bonnet fuse box, or just wishful thinking?

regards

Dave

 

[Seancruiser80]

So just to close this one off. The offending part was the A/C CUT Water SW. These are about $150 from OEM and not much less for aftermarket ones, I have disconnected so the A/C works and will wait to get a second hand one.

Where did you end up finding the faulty switch?