Heater blowers not working. Pre HE 1977

Hi All, New to the forum having just purchased a non running Pre HE XJ-S. After a week of replacing fuel lines, leaking fuel pump, 2 new fuel pressure regulators and refurbishing the AAV, I know have a purring happy Jag.

However, the heater doesn’t seem to operate, control do nothing. I have checked the fuse and that’s good. What would be the next thing to check? relays?


Good work !

There are four fuses to check

Two will be in the fuse boxes but I can’t tell you the exact positions on your '77

Two are inline fuses. One of these will be behind the RH console cheek panel on brown/brown yellow wires. The other will be behind the LH console cheek panel on the ground wire for the amplifier.

Also behind the LH cheek panel is the blower relay (which is actually four relays in one box). Check/clean/tighten those connections


This may help

Also search the archives for “Delanair MKII Manual”. If you can’t find it I can send it to your email


Excellent, Thanks very much. I should be able to sort it with that information.

Well a bit of an update. I broke down due to an open circuit ballast resistor, possibly be caused by my alternator failing a few miles earlier and running at 17 volts. I replaced the regulator in the Lucas alternator and the ballast, then noticed some pin holes and water leaking from the bottom of my header tank. A new one arrived today and the car is now driving again.

I was about to start work on the issue with the fans not working and then they suddenly came to life. Could it have been air in the cooling system? I’m not sure if the water temperature sensor by the heater would disable the fans if it wasn’t being heated.

Anyway, it’s nice to have some heat at last :slight_smile: