I decided it was time to get the A/C in my 1966 Mark X working as I plan a trip through Death Valley in the Fall. I purchased a rebuilt York 210 compressor, drier and a set of new hoses. Also purchased about 5.5lbs of R-12 Freon. Had my A/C shop drain the packing oil from the compressor and replenished it with the correct oil and then I installed the new drier and hoses (no easy feat). Before I have the Freon installed I tried to test out the fans in the evaporator but they will not turn on. Checked the fuse and it's okay. Question is, will these fans work without the compressor being engaged or must the compressor be on for the fans to run? If they should run without the compressor, what could be causing the failure?

Phil E.
Menlo Park, CA
1966 Mark X
2002 XK8

 

Hi Phil E.
Page 12 of the JCNA Jaguar Air Conditioning Judges’ Guide has the wiring diagram for the Mark X. I only see one ground and that's on the compressor clutch. Same with the 3.8S on page 36. But the picture of the 420 evaporator (NOT 420G) on page 49 it looks like the motors have their own ground to the housing. The 420 doesn't have individual blower controls so it's wiring maybe different from the 420G.

https://www.jcna.com/sites/default/f...9;%20Guide.pdf

I would first check the fuses and connections. Then I would turn on the A/C and turn the temperature switch to cold. The clutch should engage since I don't see a low pressure switch in the wiring diagram. If that doesn't work, then run a ground wire from the motors to the chassis or battery.

Let us know what happens.

 

Phil the evap. fans should be able to control w/o the compressor being engaged. I suggest powering the fans at the fan after I checked that there is power at the switch. You can easily access the switch by removing the two knurled nuts and pulling forward--remember to remove the tray above first. If you have power at the switch and the fans power remember the wiring has a very long run under the carpets and would check there. If still faulty as a JCNA member why not call the technical hotline?

 

Thanks to both of you for your insights. I will work on this over the next few days and let you know the results.

 

The issue with power to the fans in the evaporator unit was due to connecting the power to the control unit to a connector on the fuse block that for some unknown reason isn't working. Moving the connector from block 4 to block 3 resolved the issue. The system was vacuum tested for leaks and has been charged with 3 lbs of R-12 and now turns out cold air. Last issue to resolve is to find a way to tighten the a/c fan belt. As it rotates on a fixed pulley, I need to determine a means to move this pulley to increase the tension. Suggestions?

 

Phill E.
Glade you got it fixed. One of the components on that belt has to be adjustable, otherwise you couldn't get the belt on. Could it be that the belt has stretched and you may need a new one? Keep us in the loop.
Have a Great Holiday!

 

There is a pulley that is on a cam near the top of the engine. You must loosten the bolt on the back side and turn the arm to adjust. One warning---do not use a tooth belt--they will stretch out. You must use a solid belt.

 

After a massive struggle, the pulley has been moved so the belt is now properly tightened. The A/C is running perfectly (and rather frigid) - and just in time for this weeks scorching temps in the high 90's. Now one last question. What is the purpose of the spindle (see photo) which is on the bracket that connects the pump to the pulley?

Spindle under A/C fan belt