Porsche Enthusiasts Club Forum

help

got my s4 1991 back from uplands car autio today after fitting a new stereo head, now the demister is on very low, theres no noise from the fan, but hot air will come out whether you want it or not, if i use the air con it goes cold thats ok,

Have they moved something from behind the dash to disturb the fan vents

john

Possibly a vacuum hose off?

Hi John

I think they had accidentally disconnected the wire to the small fan intake for the interior sensor...

You know that little fan grill thing thats on the left middle side of the dash.... its behind that and an absolute pig to get at unless the centre console is out...

You can test it easily though...

The manual actually says this...lol..although you will not believe it....

With the ignition on and engine running....BLOW SMOKE AT THE SMALL GRILL... IF its sucked in its working...if its NOT sucked in you have found your problem.... and having changed that fan myself, personally I would take it back and get THEM to fix it...lol

All the best Brett

hi brett,

hey thank you for that, that sounds about right I will pop it back

best wishes

john

Hi John

It may not be what I suggested, so try the smoke trick first.....then take it back to them if its NOT sucked in....

All the best Brett

will do brett

many thanks

john

The valve console for the HVAC is also located in the area behind the stereo, ond if one of the numerous vacuum hoses is off it wil play havoc with the system.
Also the electrical connector for the fan control knob is very easy to pull out when you are working around that area, it happened to me twice.
If it's the sensor motor (and the connection won't pull out easily on this) you have to move the centre console to get at it, as mentioned. I'm not sure I'd want a car audio fitter to do this unless they knew about 928's, as it's quite a complex task.

good advice thank you, if its center consol out then paul anderson will have to do it,

theres a couple of things to go on thats great stuff

john

Hi John,

Not quite sure what you mean by the demister?

Anyway here's a photo of that fan motor. It would actually be very difficult to disconnect the motor without removing centre console (not a bad job, but if you can avoid it do!).

If you are a non-smoker <g> then you can also check it's connected by listening for whirr of fan. It's very quiet, so you need to be in a quiet spot.

As others have said, it's much more likely that in working in the tight space under console they have disconnected either vacuum feed to hvac manifold which sits right behind head unit. or one of the numerous connectors which route the various temp sensors to the mixer motor. If any of these sensors are open circuit then you will get hot air unless overidden by aircon.

If you can pull the head unit out then you can remove the H shaped trim in centre console, and undo the philips screws holding in hvac control head and the aircon switch/warning light console. You will then have lots of room to check whether any connectors are loose or disconnected altogether.

You can also get good access from both sides by removing the carpeted side panels which are held in by a few self-tappers hidden in carpet pile, and which just slide back and out. You may have to move seats right back (and down) to access the screws.

If the vac feed(s) have been pulled off then the best access is by removing the carpet sides.

thank you for taking the time to post that up, im taking the car back next week sometime so will gather the info to give them,

I did ask them to be careful with the car and still this kind of thing happens its crazy really especially that they are supposed to be the best audio dealers around

thanks again

john