A/C fan not blowing

[Mike Peddie]

Car : Series 1, 8V Turbo 1988

Problem : Fan for air conditioning unit has stopped blowing.

Symptoms : Air Conditioning control unit appears to be functional. Selecting a high or low temperature does cause changes in cabin air temp. The lights indicating fan speed adjust as if the control unit is attempting to change fan speed.

Connecting the fan direct to the battery terminals will turn the fan motor, but no power appears to be being fed to the fan.

The fuses are OK.

Attempted fixes : The control unit was interchanged with a unit from an S2 Thema with A/C. The S2 control unit has a button for showing external temperature and this is indicating 122 Fahrenheit!!!

Could a faulty temp sensor cause the fan to stop working?

[paul.o]

I will try to find the self test routine for the air con control unit, i think it is the same for 8v - 16v cars with air con. but it may be better to fit the 8v control unit back first before testing as the 8v outside temp probe was mounted inside the fan housing just before the fan blade and on the 16v was moved to the right hand door mirrior at some point in its production.

[paul.o]

Just nipped out to look at my spare thema which has air con . mounted in front of the air con unit below the large pipe there is the speed regulator for the electric fan. The speed regulator may be got at by removeing the bulkhead. the bulhead on my spare car was removed so i could take out the wiper rack some time ago, so i can see it straight away. if this is faulty it could be be your problem.

Diagnostic check

With the ignition on
press the auto button and the vent button at the same time on the air con control.

the temp display should display a number of dashes and then a number if a fault is found( the number is how many faults it has found)

press the vent button and the display should now show a number and a letter or two letters depending on the fault.

press the vent button until all fault codes are displayed
when all codes have been displayed the last pressing of the vent button will return the unit back to normal operating mode.

fault codes list

3C-3U blend senser ,9C-9U compressor relay, 5C-5U blend flap motor, 6C -6U air flap motor, 7C-7U air intake flap motor, AC-AU electric speed regulator
disregard 4C-4U and 8C-8U(if shown)

[paul.o]

Forgot the folowing codes

1C- 1U internal temp senser, 2C-2U external temp senser

[Daniel]

@Paul:

Since I have problems with my a/c, too, I tried to start the diagnostic check as you explained (pressing "AUTO" and "VENT" at the same time), but there is no effect (only the chosen temperature increases one degree).

Is there a special trick to start the diagnostics?

Thanks,
Daniel

[paul.o]

Try pressing the auto and vent buttons at the same time, keep them both pressed and then switch on the ignition.

[Mike]

Problem was an overheated wire in the fuse box which had melted plastic of connector and consequently insulated the contacts preventing power getting to the fan motor.

The problem was easily fixed by removing the fuse box and scraping molten plastic off the metal contacts. The wire to the fan is on the Right hand side of the fuse box.