Hi gang,
my A/C blower motor works on speed 1 and speed 2, however when switched to high speed,
there is no increase in blower motor speed. I have verified that both blowers are working.
Is there a relay for just the high speed setting?
Any and all suggestions are welcome.
1995 XJS conv.
Thanks!

 

Hi Ted,
I'm assuming you have a V12, having looked at the diagram there is a relay in both blower units which is fed from the climate control module, so as they are working on 1 and 2, the problem is not there.

The mode switch drives into the climate control module as well as the control panel module.

So, your problem could be with the mode switch, the wiring between the switch and modules or one of the modules.

Personally, I would start with the switch and go from there.

As far as I can see, there is no separate fuses or relays for the high speed setting.

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Hope this helps you,

 

Thanks Jim!

 

As Jim suggested, start with the switch. You are looking for a 4v output on pin 5 of the connector when 'high' is selected. If not you should pull the switch and test it.

If you have 4v there, then check the top connector of the CCECU. You should have 4v on Pin 15. If you don't then the problem is in the wiring between the two connectors.

Make sure you inspect the connectors and clean them if necessary.

Also, out of interest, if you turn the fan selector to 'Defrost' do you hear an increase in blower motor speed? There is a separate high speed relay in the system, you can check pin 1 of the central connector on the CCECU. There should be 10v when 'high' is selected.

Cheers,

Allan

 

Thanks Allan,
not sure about the defrost thing yet but will check. One thing I forgot to mention,
when I switch to the highest setting, I do hear a slight click noise..almost like a relay

 

The defrost setting also activates the highest fan speed, so if yours does that, the motor and relay should be fine. If not then the blower motor assembly might still be the problem.

Cheers,

Allan

 

Just checked, the defrost setting does not activate the high speed blower.

 

In that case it could be anything from the switch to the high speed relay. Best to work your way through the circuit testing at each component. You can start at either end, whichever is most convenient for you.

Let us know how you get on.

Cheers,

Allan

 

Thanks guys!
I do hear a faint "tic" in EACH blower motor housing when switched from speed 2 to high speed...and then again when switched back to a lower speed.