Can someone help me understand why the #10 fuse on the right side would shut down my a/c? if someone has an 89 or so could you pull the #10 fuse and see if your a/c goes out as well?
will do it in 1 hour and reply
I pulled 10 fuse20a yellow and the air stayed on. no 10 fuse in the handbook gives the list I gave you before , inside the the cover of the fuse box it says 20a auxiliary circuits.11 fuse is for air con clutch, air con, cooling fan.
Thanks for the info but for some reason when the #10fuse was out(problem is the sunroof motor) the ac wouldn’t work, makes no sense but that’s what happened. I disconnected the sunroof and now the ac works.
My car is a 93 so probably different, have you checked the rear of the fuse box for cracked solder joints ? It’s a well known problem on XJ40’s. Even if the fuse 10 is not related to the air con system, maybe when it’s removed the board flexes slightly and a cracked joint around the relevant fuse for the air con (11 ?) opens up causing the AC to drop out.
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That is possible but the blown fuse was still in place. Definitely has me stumped.
David …
Keep in mind the age of the car and over the years what modifications (work arounds) may have been secretly 
done.
So when all the fuses are in, the A/C does work?
We I unplugged the sunroof motor and #10 did not blow and now the ac and radio work.
correction went to check the ac and #10 is blown,sunroof unplugged cigar lighter unplugged and radio, blows as soon as I turn on ignition! Damn! And the ac and radio are out, suggestions?
David …
Here’s the complete wiring diagram for your '89 XJ40. Once you understand the symbols for the connectors, grounds, wire colors, etc. it all makes sense.
http://jagrepair.com/images/Electrical/Elect-Tech%20All2/89%20XJ6%20Electrical.pdf
I can’t open the link.
It opens fine for me. It’s a pdf file so maybe that’s the problem. I’m using an Apple Mac computer.
Perhaps you can download a pdf reader like adobe acrobat.
It’s very detailed and quite lengthy with around 30 diagrams. VERY good info.
I’m on a PC and the link opened fine here too.
OK, the short answer as to why your A/C doesn’t work when the #10 fuse is blown is because that fuse feeds power to the A/C-Radio relay, shown in Figs. 27 and 28.
As to why fuse #10 is blowing, that fuse supplies power to a number of different auxiliary circuits as shown in Fig. 1, including the door lock heaters, for example, as shown in Fig. 20. The wiring from the fuse panel to those heaters is in the wiring bundle that exits the A pillars and enters the forward edge of the front doors. You might have a close look at the wires in those bundles -especially a slate/gray one - to see if any have worn off or broken insulation that would be allowing the wires to short or ground out.
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Yes the insulation in the door entry wires is worn out, definitely going to check those wires closely.
I just pulled the #10 fuse and it does indeed shut down the A/C because among other things it removes power to the console climate control panel.
David were you ever able to open the electrical diagrams ?
If the wires aren’t broken, instead of excising the “worn out” (bad insulation) sections of wire and replacing with new you can wrap the individual wires with electrical tape or apply liquid insulation to shield any bare sections. The object, of course, is to keep bare wires from touching one another or metal body bits (doors, door pillars, etc.).
That would require me being ae to work my computer some how, no I wasn’t able to open it but there was a post about wites to the doors, and an ac radio relay which I hope to loacte.
The A/C-Radio relay is on a relay panel beneath the dash, right side. The wires to the relay base will be blue, light green/orange, and brown/white.
Is that the panel behind the fusebox or above the knees?