Cold Heater!

[rholt]

Hello everyone, i'm looking for some technical help. The heater on my '89 Turbo just won't blow out hot air. The temperature dial has no effect, but when I press the windscreen demister button, hot air does come out of the wndscreen vents. [] When I turn it off, back to cold [&:]. No problem in summer but no so good now it's getting a bit chilly! Any ideas anyone?

On a seperate note, what is the significance of the 951/952 numbers I've seen in connection with Turbo's? Does it apply to specific models? Thanks again.

Richard

 

[zcacogp]

Heating issues seem to be a function of the levers which move the air-control flaps not doing what they are meant to. More specifically, they connect to the flaps by means of some flimsy (brittle) plastic clips, which break, leaving no flap control. (I'm speaking from theory here, rather than hands-on experience.) An investigation may well reveal the broken clips, and the cause of the problem. And, when you are done, would you mind having a look at mine, which has the same problem! [] (Yes, that's why I know the theory!)

The other possibility seems to be that there is a multi plug under the scuttle, where the heater control plugs in, and this gets dirty. If you can identify the right multiplug, pull it out and clean it, then it may get it working fine.

944 is the Porsche model, and the Porsche internal model designation for the LHD 944 Turbo was 951. When they produced the RHD 944 Turbo they called it a 952. The boostie boys on here are keen to underline their 'elite' nature by referring to their cars with different numbers to the rest of us - hence calling them 951's. All those who drive superior S2's are far too polite to point out that they are actually wrong - they almost all have 952's.


Oli.

 

[Riverside]

ORIGINAL: zcacogp

All those who drive superior S2's are far too polite to point out that they are actually wrong - they almost all have 952's.

Would you be a 945 S2 owner? []

I had the same heater problem when I first got mine, it turned out to be one of the three thermistors that had failed open (they usually fail closed, causing full heat). When you press the screen demist button & get full heat to the screen that confirms there isn't anything mechanically wrong with your heater.

There's a diagnostic section in the Porsche manuals for the HVAC electronics, you'll need a multimeter.

 

[Fen]

I don't think it can have as drastic an effect as this, but what used to be called "the unknown pipe" which connects the fan on the bulkhead to the little grill on the dash near the clock needs to be connected on both ends. It's a relatively quick job to check it and probably also worth pulling it off the fan end to check there isn't 20 years worth of lint blocking the flow.

It's how the heating senses the cabin temperature so if it isn't pulling cabin air through it doesn't know the temperature, but as I said it doesn't have enough effect to cause full cold all the time, just fluctuating cabin temp.

 

[Diver944]

My memory is very rusty about this but myself and another Titanicer had the exact same problem about 8 years ago and it was the thermistor under the plastic shroud in the engine bay just in front of the steering wheel. It's job is to sense the outside temperature and adjust the internal temperature accordingly. When it fails it tells the control unit that it is very hot outside so the heater does not allow any heat from the engine into the car. It was under £20 from the OPC back then

 

[zcacogp]

ORIGINAL: Riverside
Would you be a 945 S2 owner? []

Interesting - 945 being (presumably) the true designation of a RHD 944?

Logical, I guess. But I didn't know that. Thanks.


Oli.

 

[rholt]

Thanks for the advice every one - I'll let you know how I get on.

Richard
952 Owner!

 

[Diver944]

Oooh I managed to find a very old picture on my hard drive. The sensor is the 1 inch long plastic tube at the top RH corner of the mesh grille and it's part number is 964.659.120.00