All,
I am trying to locate the Fan speed relay on an '87. The fan does not work on Medium but does on defrost, Low and High.
I have an '86 that was easy enough to find. Inside the little panel with the foot vents on the front of the console on the drivers side. Held in place on two posts with 10mm nuts. Has 12 electrical connection points. The '86 fan does not work on Hi but does on Defrost, Low and Medium.

The '87 has nothing where the '86 relay is located, no mounting posts and no plethora of wiring connectors.
Additionally I have the Delanaire 3 unit from an '88 XJS in the garage. No relay on that unit either.

My Haynes Manual shows the location where the '86 is located.

Any help is appreciated.

 

Your '87 likely has the Mk III system as well. Thus, no stand-alone fan speed relay as found on the Mk II system.

My Feb '87 build XJS had the Mark III system. I think usage began late 1986 calendar year.

Cheers
DD

 

Thanks Doug,
Yes, My '87 car was a12/86 build. The '86 was built in 02/86.

Sooooo......does the '87 have a relay of any sorts for the fan speeds. As mentioned the '87 does not work on Medium. If not any other repair recommendations.

 

It should have a relay for ON/OFF and a transistor emitter/collector shorting (high speed) relay in the case under the fresh air flap.
Speeds are controlled 'electronically'.

 

Is relay and the transiistor emitter/collector on the Delanaire 3 or the blower motors?

 

Do you not have the Tech Guide for the Delanair MKIII ?
It is available in .pdf everywhere on the internet.

JAGUAR SERVICE
BLOWER MOTOR SPEED DRIVE CONTROL
Mounted in the outlet of the blower motor units are heatsink assemblies, each of which consist
of an interface suppressor diode, a feedback isolation diode and a power transistor.
The unit is supplied with positive battery voltage via an ignition controlled fuse. With the fan
motor running at high speed, a relay is energized with a voltage from pin 16 of the control module,
thus closing the relay contacts.
On all other fan speeds the ground circuit for the fan motor is via the power transistor and the
control module.
The feedback diode enables the control module to sense the voltage at the negative terminal of
the fan motor and so calculate the speed of the blower motor.

 

Mucho Gracias!!!

 

I would look at the micro switches on the mode control if the blowers work on low and high, but not medium. High is through a relay in the blower assembly (right side I believe), low speed is PWM through individual Darlington transistors on each blower assembly. If you have low, that would indicate to me that the transistors are ok, and if you have high, the relay is ok.