heater box

[graham]

Can someone tell me what this is fitted to the top of the heaterbox.It has a single and a double spade connector???

[Craig Elliott]

I'm not 100% sure but I have a feeling its a resistor for the fan - If I recall correctly the two tabs close together are for the "fast" blower setting and the one on it's own is the slow... (i.e. the power to the fan is fed through a resistor).

C

[niallf]

I'm not 100% sure but I have a feeling its a resistor for the fan

Yes, that's exactly what it is. If it's broken (which mine was) it means the mid speed doesn't work. Unobtainable as far as I could find out, but I replaced with a wirewound resistor I had from an old VW Golf I happened to have lying around.
Niall

[bob_rich]

Hi Graham

definitely the resistor to reduce the motor speed on the low setting. On mine a blue lead went from one of the double terminals to the motor. Then the fan switch either switches ground (high) to the motor on the other double terminal or ground via the resistor (low) on the single terminal. The resistor look like around 1.2ohms. Should be fairly straight forward to pick up a replacement. Scrap yard or an electronics component supplier something around 1 to 1.5ohms and 25Watts rating should be OK

Best of Luck

Bob

[rjaxe]

If you want to keep the original device its worth dissmantling it and giving the connetions a good clean. The resistor is pretty robust but suffers from corrosion, drill out the rivets holding the spades and the contact washer underneath, clean it up and re-rivet the lot back together, worked fine with mine.

[stugilmour]

Graham:

I just re-looked at the heater switch, resister & motor wiring based on Bob's remarks above. My car uses the resistor and switch on the power side of the circuit to the fan motor, where Bob indicates his uses the ground side. It's another case of both are correct; I expect mine is an earlier car than Bob's. The wiring changed at some point according to the diagrams I have.

When I assembled my resistor to the heater body I noticed I had potential on the heater body; not a full 12 volts but a couple of volts if I recall correctly. I solved this by insulating the resistor from the steel body with a bit of cardboard at the screw mount & the resistor assembly flange. I did not check the rivets as suggested by rjaxe, so this may be the issue I had and didn't know it. Something to check for perhaps. Maybe this is why the wiring was changed so the resistor is thru the ground side, not sure.

Anyway, both wiring set-ups will work, but could lead to a bit of confusion on how to set your's up depending on loom specifics.

[graham]

Thanks guys for the replies - will have to find the wires from the switch on the dash to work out solutions. Black wire on heater motor has spade terminal so maybe we start there.
Just another hiccup in the resurection of a car with classic lines
Graham