Ok. So I just bought this beautiful 1991 Jaguar Vanden Plas. I was getting around to fixing the A/C (made a post already) because both blowers aren't working. And then I would fix all of the other "little" problems. But I have a feeling all of the other "little" problems is the same problem as the A/C. I find it strange for both blowers to just stop working.

The other problems are all electrical. On the AC instrament panel, all the bulbs are illuminated and non turn off or on when you click buttons. Door unlock buttons don't work, in fact it just rolls up the windows. Car can't lock or unlock and the right side seat belt motor doesn't go down or up. What do you guys think the problem is and where should I start looking?

And yes, I did check the fuses on the LHS, RHS and Center Console lol

 

Hi cjcarson,
As I may have mentioned in your A/C thread, it is unlikely that both blower motors did fail at the same time. Usually one blower fails and the owner continues to drive the car until the other blower fails. There are plenty of known causes for blower motor failure and I may have mentioned some of them in your other post, which is where you should maintain all your discussions about the A/C system to avoid duplicate effort on the part of other members.


Regarding the seat belt motor, it is covered by a lifetime warranty so you should contact a Jaguar dealership about having it repaired at no cost to you. If the dealership gives you a hard time, search this forum for information on the lifetime warranty that you can use to compel the dealership to cooperate.

The door lock issues may have something to do with the driver's door switch package, door lock actuators that are seized or out of synchronization, a problem with the Central Processing Unit, which manages central locking, or some other issue. You can download the wiring schematics here:

Jaguar XJ40 Electrical Guide 1991

Cheers,

Don

 

Fuse box is probably in need of a reflow. Im going to have to do the same very soon.

 

What is a reflow? How much does it cost and how do you know if it needs done lol

 

The fuse box has to come out, and then the soldering points have to be reheated, allowing the solder to flow again, making a solid connection.

 

Ok. Here is the update lol. I still need help. I took the Jag to a mechanic. He tested the blowers and they work. He is saying that he believes it's the microprocessor, he needs to find the schematics for that, but is having a hard time doing that. What are yall's thoughts and where can I find that schematic.

 

Hi cjcarson,

The schematics are available in the Electrical Guide which I provided a link to in Post #2 of this thread....

If the blower motors run when 12 volts is applied directly to the motor terminals, the most likely cause of malfunction when installed in the car are a failed relay or a failed speed-control circuit, all of which are mounted in the blower motor housings. There is plenty of information available on how to repair the speed control circuits. See this section of the Jag-Lovers XJ40 eBook:

Air Con Blowers

Air Con Blower Testing

The rest of the XJ40 eBook is a good reference:

Jag-Lovers XJ40 eBook

The Haynes Repair manual is also invaluable. You can download a mostly-complete U.K. edition here:

Haynes Jaguar XJ40 Repair Manual

If your control panel isn't working it may be a small microswitch on the rear of the panel that can be replaced. Lots of information about this in the Jag-Lovers archives.

Cheers,

Don

 

Did you already re-flow the fuse boxes like @Brewtech suggested?

Larry