My heater isn't working, blower is working fine on both sides but blowing cold no heat at all, any thoughts, it's a 91 C4, thanks

 

Try THIS LINK Post # 7.

 

Any work, projects, etc., done lately on the car? Or did it just decided to quit working "out of the blue" today?

 

Kovic: Go to ToreBergvill.com, click CARS @ top of page, then "porsche climate control diagnosis faultfinding", etc. Gives near quintessential description of the entire system, and may help your tracing out the prob. Cheers

 

No work done on car, it just stopped working... After the wife drove it forgot to mention car is non air con

 

i'm in walsall and have a bosch hammer if you want to pass by to connect it up?

 

Many thanks, going to check some things then if no success I'll pm you

 

I am in Moseley have pst2 tester and can probably fix your heater if you like

 

is the car running and warmed up?....sometimes its the simplest things.....LOL

 

sorry...just couldn't resist

 

There is a sensor on the back of the control unit. My system was acting up last year. I took out the unit and cleaned the sensor and it worked better.

There were other things wrong (stuck flapper) that contributed.

Mine take a few days to go from hot to cold air... It's like the flappers just take their own sweet time....

 

No heat is probably due to malfunctioning mixer servos. These control the amount of heated air from the engine. The servos are all placed under the black plastic cover under the windscreen in the luggage compartment. It's easy to spot any movement on them, have a mate to turn the temp dial to min and max and see if they move.
The most probable cause is weared out servos, they must be replaced. However, inert servos can be due to a fault inside the CCU as well.
The easiest way to test this is to plug in a new servo and see if this moves OK. You could even use one of the servos that are placed nearby and maybe just stretch the cable harness to reach this.
A CCU fault is indeed repairable too, but I would recommend to check the servos first. You could also use an OBD tool to read out any fault codes from the CCU to determine the culprit.
Details here: www.ccu.tore.bergvill.com
Cheers,
Tore

 

Many thanks for everyone's help, hopefully seems to be a straight forward fix

 

Does the blower only run when you have the heating on the cold setting? ie. As soon as you turn the temp up, the blower stops?

If so, it's a blown fuse in the rear fuse box (in the engine bay). The usual cause of this is bad bearings on the rear blower motor (also inthe engine bay). Try replcing the fuse if it's blown and if it blows again, you'll need to either buy a new rear blower motor or fit new bearings to it.

 

Blower works fine on cold setting as well