rear heater blower

[Bazzer]

Having just read the latest edition of the Porsche mag I have a question about the small extra blower fitted to the heater system which helps to blow hot air to the cabin which is situated on the top of the engine on the left hand side.

I know the motor works as I have run a direct feed to it but somewhere along the line there is a fault, could someone tell me where the relay is situated and is this motor supposed to work when you turn the control knob between the seats?.

One other quicky, the senser that fit's into the rear heater pipe by the left hand butterfly valve, is this supposed to be fitted into the metal part of the valve or can you get away with fitting it into the red heat resistant pipe if sealed properly, assuming it locates before the valve and not after, sorry chap's but this is all new to
me!!!

Thank's Baz

 

[Guest]

Hi Bazzer,
The relay is in the engine bay on the left side as you open the engine lid.
My Bentley manual shows 2 relays mounted on a horizontal plate(1978 to 1980 )and one relay for (1981 to 1983) with 3 fuses on the vertical plate. The hot air blower motor relay is closest to the fuses or closest to the centre of the car.
The blower motor on my car runs when I turn the heat control knob. You also need to check the link arm connecting the servo motor to the lever which operates the butterfly valves under the car, if this link arm has disconnected or fallen off ( as mine had) the blower motor will not run. This link rod can be accesses by removing the side panel cover of the heat control unit mounted between the seats. The panel is about 50mm square. The link rod has 2 plastic ball socket joints at each end. The lenght of this rod between the centres of the ball ends should be 124mm +/- 2mm. I purchased my new plactic ball ends from Specialist cars of Malton.
My view on the position of the sensor is that it should be in the same position or as close as possible to the correct position and well secured, this should be OK.
Cheers
John

 

[Bazzer]

Cheers John, that makes sense, I know the arm is still connected as I have fitted new butterfly valves and know these work fine, from what you have said I presume the knob between the seats is also the power switch to the motor, so if it still does not run do I assume either the relay has gone or possibly need to rewire from the switch to the relay, is there anything else wireing wise relevant to this motor.
Sorry to appear a little dim but am still finding my way around this beauty!

Baz

 

[sib8292]

Bazzer when you say the butterfly valves work fine, do you mean that you can operate them using the red lever? Or that the electric servo works the valves for you?

The first means that you have disconnected the rod from the servo, which could be why the hot air motor does not work.

If the servo is working the valves, the question is whether there is power getting to the motor. Its one thing checking that the motor works and another that the suply is getting to it! If power is not getting to the moptor then the problem may well lie with the relay or possibly with the little fuseplate at the rear of the engine compartment. Try cleaning up the contacts in that fusebox. To test the relay, you can swop with one of those in the front fuse compartment and see if that works

 

[Bazzer]

The valves operate when turning the knob between the seats and I get hot air into the car, the only thing that appears not to be working via the knob is the hot air blower motor itself , the red lever also goes up and down when turning this.
Thanks for the advice on the fuses and relay I will now give that a go.

Baz

 

[lesworth]

ORIGINAL: Bazzer

..... I have fitted new butterfly valves and know these work fine....

Baz,

Did you have trouble removing the nuts from the old valves? I understand this can be tricky without breaking the fixing studs. I want to replace mine at some point so would be interested in how easy / difficult you found this.

Les.

 

[Guest]

Hi Les,
Don't know about Baz but I removes the nuts on my car which hold on the heater flap valves with no problem at all. Just a splash of WD40 and worked the nuts backward and forward i.e. undo 1/2 turn retighten 1/2 turn until they came off.
Cheers
John

 

[Bazzer]

No problem Les and I think mine had been on there 30 years, well rusty, infact no valves left at all, but same as John just lubed them up and off they came, the hardest bit was getting the new valves over the old studs as these appeared to have had a little bending and twisting at some point over the years.

Cheers Baz

 

[lesworth]

Great - I feel much more confident tackling this job now.

 

[Bazgillie]

When fitting new valves it is important to set them to the closed position with the dial on the lowest setting or they will let hot air through a cook you in the summer. The fan in the engine compartment is only there for when you are doing low revs, as the revs build up the main engine fan takes over and pushes the air through the heat exchangers. Lots of people remove the motor and fan to backdate the heating, saves a bit of weight and les to go wrong.
Hope this helps Baz Gillie