Climate Controller Quick Question?
Thread Starter
Racer
Joined: Nov 2010
Posts: 258
Likes: 0
From: North Wales
Climate Controller Quick Question?
Not sure if this is normal, and I may have added to the problem but this is where I'm at:
I had the AC compressor removed along with some rubber flow/return flexible supply pipes from the engine bay as I was told initially when I got the car that the AC rarely worked in the 964 and being in the UK the 2 weeks it does get hot, I want to feel the pain! So it was removed.
However fan unit seems to blow randomly, I set the temp control set point to blue dot or 16degrees C and recently regardless of where I set fan speed dial from 0/1/2/3/4 it seemed to blow at max, but would also stop for a minute when I adjusted the temp guage up/down, but blow full on again.
This weekend I kind of found possible clue, if I set the temp set point dial to a setting which is near to the actual cabin air temperature, then the fan speed dial then becomes active again and I can adjust the fan speed from 0 (off) to 4 and it step up/down if speed perfectly.
So the temp dial has to be near to actual cabin temperature before allowing normal fan speed adjuster to become active?
So I am assuming that when temperature dial is set very low or high, your fan speed set point is ignored and fan operates to try and satisfy the temperature set point in an override mode??
Does anyone know if there is an on-board air temp sensor build into to the AC controller, and if your controller strategy works like the above?
Or I might just have a stuffed controller!
I had the AC compressor removed along with some rubber flow/return flexible supply pipes from the engine bay as I was told initially when I got the car that the AC rarely worked in the 964 and being in the UK the 2 weeks it does get hot, I want to feel the pain! So it was removed.
However fan unit seems to blow randomly, I set the temp control set point to blue dot or 16degrees C and recently regardless of where I set fan speed dial from 0/1/2/3/4 it seemed to blow at max, but would also stop for a minute when I adjusted the temp guage up/down, but blow full on again.
This weekend I kind of found possible clue, if I set the temp set point dial to a setting which is near to the actual cabin air temperature, then the fan speed dial then becomes active again and I can adjust the fan speed from 0 (off) to 4 and it step up/down if speed perfectly.
So the temp dial has to be near to actual cabin temperature before allowing normal fan speed adjuster to become active?
So I am assuming that when temperature dial is set very low or high, your fan speed set point is ignored and fan operates to try and satisfy the temperature set point in an override mode??
Does anyone know if there is an on-board air temp sensor build into to the AC controller, and if your controller strategy works like the above?
Or I might just have a stuffed controller!
Drifting
Joined: Sep 2010
Posts: 2,591
Likes: 19
From: Philly 'burbs
I believe the only temperature sensor is in the CCU. If you look at this image*
it is inside the little circular hole behind the l'il grille on the far left. (next to recirculation button) There is a fan that sucks in cabin air to sample and adjust accordingly. Perhaps the the sensor is gunked up in dust, and/or perhaps the little fan isn't sucking in air (You can hear the fan run inside the dash for a few minutes after shutdown)
The CCU slides out like a radio, and the fan is mounted on the back. Removing and cleaning is a 1 hour job. Couldn't hurt if it's never been done.
(*stolen from HERE )
it is inside the little circular hole behind the l'il grille on the far left. (next to recirculation button) There is a fan that sucks in cabin air to sample and adjust accordingly. Perhaps the the sensor is gunked up in dust, and/or perhaps the little fan isn't sucking in air (You can hear the fan run inside the dash for a few minutes after shutdown)
The CCU slides out like a radio, and the fan is mounted on the back. Removing and cleaning is a 1 hour job. Couldn't hurt if it's never been done.
(*stolen from HERE )