Just picked up a 1977 XJ-S two days ago and enjoyed a brief blast of fresh, cool air before my glory was cut short on my way to work. Previously the A/C would work only if I were to put the right-hand knob juuuust so between "off" and "low". Any setting of the fan control knob would kick on the compressor but only that one spot would spool up the blower motors.

Fast forward to today and now no setting on the fan control knob will make the fan come on *or* activate the A/C compressor. However I do hear a faint "pop" from the speakers when I turn it so at least one of the microswitches is working enough to make *something* happen. Worth noting that the actual temperature control servos are completely dead but I couldn't possibly care less at this moment. What I'm trying to find is fairly simple (in my mind, at least)

I'd like to find the wire for the A/C compressor clutch, right blower, and left blower. Preferably easy to get to under the dash so I can clamp a vampire fitting on them (or solder in a wire) and connect them all to trio of toggle switches giving me the manual ability to turn on the blowers and compressor. Wiring diagrams with colors would be a huge help but I can't find anything useful on the internet.

I did find the attached photo behind the scuttle panel on the right-hand side. I assume the large-gauge red wires have something to do with blower motor operation but I'll be 12 feet under before I figure out exactly what and I'm not a huge fan of randomly probing around with +12v until something does stuff.

Thanks,
Jake

 

Firstly welcome to the Forum.

When time permits, do an Intro in the New Members Area.

My findings over many years.

Remove the radio, remove the 2 knobs of the climate system. Remove the 2 nuts under those knobs, CAREFULLY remove the facia trim, watching for the fibre optic tubes in there.

Look at the RH switch shaft, and at 12 and 6 o'clock are 2 SMALL hex heads. Feel behind them, and the 2 small nuts can be "felt". Push your finger on those nuts and tighten the 2 bolts. NOT STUPID tight, just nice and firm. This will maybe only be 1/2 of a turn or so.

This will "tighten" the switch pack, and restore proper operation of the RH dial.

NEXT

Remove the RH console trim cheek, and look up towards the windscreen, and in a position that the passengers Left knee would be, and you will see (if you are lucky) an inline plastic fuse holder. That fuse it the key to the fan system, and blows regularly. I fit a 10amp in there and move on.