Porsche Enthusiasts Club Forum

Right ive got an oval dash car with no heating.

Ive done a lot of research so far, heres what I know.

The system is designed to fail open (hot) mine has failed cold.

The flaps for directing the air dont work, but the blower motor does work at all the different speeds.

If you pull the vac hose from the control valve under the bonnet then the heater comes on.

I have bought a new heater control panel which has made no difference

I have checked all the push rods and no plastic clips have broken.

It looks like an electrical fault, under the dash I have found two plugs in the passenger footwell in the ECU area but cant find anything they will plug into in range.

Ive checked fuses, so what have I missed gents?

James, can you prove either of the vac control units on another car?

Less of a problem now, but if you go back far enough then these items had a reputation for failing regularly. Its always possible that youve replaced bad with bad and whilst I suspect that youre right about a fault elsewhere, youre going to need to rule out the controller before trying to find it.



Simon

Where is the second vac unit? and what controls the vacuum? What ever controls it is telling the vac to suck which is why when i pull the hose off i see the arm move and it opens the valve allowing the hot water the circulate.

But that tells me at least that valve works, your right about the heater control though. It was bought on ebay from Fazepart who said it had been tested. So as they're a company and said it worked I thought I stood more chance of it working than from a private sale.

is there a means of testing the controller? I re soldered a lot of stuff on the old one and checked a lock with a multi meter.

Is there a relay im missing? And what controls the vacuum?

Sorry for causing confusion.

Can you prove either of the heater control units that you have: either the original or the replacement?

I would view any replacement as suspect until Id extablished otherwise because they used to be one of the most popular and quickly selling items (along with door handles, window regulators and front bumper and bumper lamps).

Unless i speak very nicely to my friends dad who also has an oval dash car I dont think I can. Is there a known test or a pin out diagram and I can bench test it? I didnt see anything on clarks?

I understand the heater controller are a common failing point but have seen no knowledge on what it is that fails?

Have got another heater controller on its way, lets see if that cures it

i have the same problem on my cab. i have tried swapping bits over from my S2 and the problems still there.
I have put it down to 20 plus years of tap water being used and furring up the heater radiator.
Its only a guess, i may pick up a spare rad and de scale it and fit in the summer ( when i need the heater now! )
Anybody else had to do this?

Hmmmm, my heater went off tonight, but i did plug a vacume hose back in that had bee left unplugged. . . . . sculdugery afoot i,ll be bound. . . !
So how do i fix it then. . .

Sounds like the same fault as mine. If it is we don't know how to fix it yet