Heater Valve Motor Help

[Marty V8]

Hi,

I have finally decided to refit the electic motor to the heater valve, having run the car with it uncoupled for a while. Whilst swapping valves over on the motor (I bought a new one to replace the existing) I have successfully managed to snap off two of the three connectors that are connected to some sort of variable resistor - shown as the round black doo-dah in the photo attached below. I re-soldered the the connections, but now the motor wont settle but continues to twich one way and the other, or just tries to keep turning in one direction. I think I may have damaged the internals of this electric thingy due to heat transfer from the soldering iron.




Does anyone know what this thing is, and whether I can get a replacement for it; or do I have to buy a whole new motor assembly?

Thanks

Marty

[Loubaruch]

Are you sure you put the wires back in the correct place? It is simply a variable resistor, if it is damaged maplins should have something similar or RS components.

Unsolder the wires and with a multimeter measure the resistance between the connections, 2 should measure a constant value (10KOhms from memory) the third (the slider) should measure from 0 to 10kOhm:

This may help:
http://www.bertram-hill.co.uk/Pages/TVRGriffith.as...

[Marty V8]

Loubaruch said:

Are you sure you put the wires back in the correct place? It is simply a variable resistor, if it is damaged maplins should have something similar or RS components.

Unsolder the wires and with a multimeter measure the resistance between the connections, 2 should measure a constant value (10KOhms from memory) the third (the slider) should measure from 0 to 10kOhm:

This may help:
http://www.bertram-hill.co.uk/Pages/TVRGriffith.as...

Thanks for the reply.

I have photos of the wiring before I managed to break them off, so yes, they have gone back in the same order.

I'll check the resistances across the poles and if all else fails, I'll try Maplins/RS.

Cheers

Marty

[Marty V8]

Quick update.

Checked variable resistor with a multimeter and it seemed to have a couple of 'dead spots.' Maplins provided another for the huge sum of something like 60p. New resistor connected and it works like a dream and coupled to a new heater valve I can now get total closure of the valve.

Now just got the messy job of draining some coolant and plumbing in the new valve.

Cheers Loubaruch

[Loubaruch]

Glad you got it sorted. Just to cheer you up, dont be too surprised if the cockpit still gets warm even with the valve fully closed, some cars seem to suffer much more than others. I had to put a stop tap in the main heater feed from the block to cool things down.

[Marty V8]

Yeah, there's a lot of potential heat soak from the big heater under the bonnet.

I replaced the original valve a couple of years ago and currently have it installed in the heater pipework. Its not currently wired up and I have to reach underneath the glove box to change temp via the lever that came attached to it. I can get cold air through the system with it in 'manual' mode so am hoping that when I wire another in it will also work as well. Photo attached shows the new valve and the existing one removed. The existing one has the open and closed end stops filed off.

Its worth getting a new valve to replace the existing. I took my old one out and found out that it would only just shut off through an extremely small angular rotation and it would have been almost impossible to 'tune' the closed position with it insitu.

Having got another new valve and tried it wired up - Ive got the heater ECU and the wiring pulled out through the stereo panel at the min to test it all - there is a definate improvement over the old one. For the small cost, its worth buying and even if they wear quickly and only last a couple of years, its a cheap part to replace.

When I refurbished the car in 2010/2011 I made up new heat shield matting that extends further down the inner wings in the hope that this will reflect some heat as well. So far it seems to have worked.

Cheers

Marty

Edited by Marty V8 on Thursday 26th April 18:36

[David Beer]

I found my valve crept open when the ecu warmed up, so using the spare push switch on the temp control, it can not move unless it is turned on. I think that makes sense !

[Loubaruch]

David, thats interesting, perhaps the reason some cars seem to suffer and others dont, I must have a squint at the valve after a good run. Before installing a simple timer on the boot lock I used the panic switch on the dash in series with the boot lock switch to minimise motor burn out. The chances of them both sticking are low. Had to do something after burning out 2 motors.

[David Beer]

I have never heard of burnt solenoids, rather burnt motors within. Is the mechanism nice and free working, mine pops open within a second.

[Loubaruch]

The boot release button had a habit of sticking On (before I modified the dash) thus burning out the boot lid release motor. Since fitting a simple circuit 7 years ago no further problems. Boot lid always has released instantly.

http://www.bertram-hill.co.uk/Pages/TVRGriffith.as...

[David Beer]

Only three views on this subject shows its not a problem. I would of changed the switch , good on you for not upsetting the dash.