Daveayerstdavies

I'm currently working on a 1986 944 that has a heater control problem. It blows permanently hot, whatever position the controller is set to.

I thought it would be the usual problem of a broken clip on the servomotor arm that operates the hot/cold air-mix door. It is a RHD car so the controls are in the passenger footwell next to the passenger's right knee. Unfortunately in the right hand drive 944 you have to remove the glovebox to see the three servomotors and actuating rods. Once I had removed the glovebox and revealed the side of the heater assembly, I was surprised to see all the mechanical parts still attached. On closer inspection, the clip on the air mix control was slightly broken and in need of replacement, but not yet so broken as to stop the arm working. I tested the controls and found all to be working apart from the hot/cold air mix control. The servomotor just doesn't move.

Is it most likely to be the controller or the servomotor that is faulty?

How can I determine if the servomotor is getting drive from the controller unit?

Wipeout

One thing I've done with some success is turn the temp **** to full hot with the fan on high for about a minute, then turn it back. Might fix it, might not. If it was "stuck," that can fix the problem.

Daveayerstdavies

I think it might be beyond that, but anything is worth a try!

I'll let you know.

Daveayerstdavies

Sorry. I tried it but still the servos refuse to budge a millimetre.

Any other thoughts still welcome!!