Hi to alls
The car heating and ventilating system consists of a heating element and 2-speed electrically driven fan on the Jaguar MK 2.
Only one speed works: the lowest one.
How do I fix this malfunction ?

Thanks in advance for your advices.
My best regards
Gérard

 

Could be the switch. You could try some Contact spray. If you are comfortable reading the wiring diagram you could use a jumper wire to see if it’s the switch.

 

I agree it could be the switch.

exercising the switch up and down might give a hint if by chance you get the fan's High speed.

 

If it's not faulty switch, check if cable GY is broken