heater blower

[nige]

Hi everyone I have a right pain of a problem. The heater blower in my 1.9Diesel finally stopped working, its been getting slower and slower and a bit hit and miss for the last few years, it used to take a thump to work but now dead. So bought another from a breakers. It seemed to work fine .. then it it stopped working too.

There are two connectors on the fan, one goes into a heavy duty PCB board am assuming this is the variable control, out of this is a heavy duty 2 wire feed to the fan. If I connect the 2 wire plug to 12V the fan works fine.

The fan control knob looks like it opens and shuts the air flap does this have any control over the fan speed as well?? I know sounds a daft question. I have now managed to knacker the mechanism that opens the flap, I can close it from the knob but it wont open. Any idea how I get to the control knob and check out this
mechanism

I have some options I guess
1.Does any one foresee any problems if I wire the 12V fan directly to an on/off switch to the dashboard, and wedge the flap open?

2. Could there be an issue with the heavy duty PCB?

3. Is the an electrical connection as well as mechanical control on the fan knob, and if so any ideas how I get into this

Can anyone offer any advice – I know it seems a bit trivial but its my my wifes car, she uses it every day for work and with the winter coming I realy need to be able to demist the windows.

Any help gratefully received

Thanks
Nige

[Tim Leech]

Ive got a couple of spare motors if you need one.

[Defender110]

Sounds like it might be the common earthing track problem, if you read through this thread further in there are several posts on joining connections 2&3 together to get a new earth.

http://www.bxclub.co.uk/forum/viewtopic.php?f=15&t=5515" onclick="window.open(this.href);return false;

[mat_fenwick]

In my experience the earthing problem causes sudden failure to work, so it could be that but teh fact you had lesser problems before that suggest it could be something else. The tracks on the PCB behind the knob can wear out or get dirty, so cleaning those up may work.

A simple on/off switch of sufficient current rating (or a smaller switch to operate a relay) would do as a temporary solution until you can solve the problem.

[mds141]

There's a NOS heater blower on eBay at the mo.

[nige]

brilliajt.! I am going to rig up a temp switch relay and fuse or the moment and have a direct on/off

Could someone confirm that the knob also opens and closes an air flap - mine can only close and is stiff cant get it to open again, is this going to be a pain to sort?

thank you

[nige]

also, the pcb in the fan is a voltage control board? - is this also do to with voltage control to the fan - ie variable fan speed and taking the higher current so does high current does not have to go through the knob?

[mat_fenwick]

The PCB behind the knob controls a small current going to a large transistor on the PCB in the blower casing, which controls the main current to the motor. This transistor may have failed, but it relies on a connection to the (metal) case of the transistor to complete the circuit. So if corrosion is present, if will stop the blower from working.

The only thing which can really go wrong with the PCB behind the knob, is that the tracks which give a variable resistance can wear out with use. This should be obvious if you pull off the white plastic rotator from the PCB, taking care not to loose the two springs and contact between it and the board.

This has more information on the transistor. Which part of the car did you have to hit to get it going previously? Dashboard or blower casing? That may be a pointer to where the likely problem is.

[nige]

i bashed the fan case housing, suspecting the old fan bearings were causing it to seize at it did feel tight and sticky. Got a new fan from the breakers though in both the pcb is well shot, however in messing about with it all i have busted the fan control knob - hence was wondering what kind of a job it is to repair the air flap from the knob cable. I think in hindsight orignaly i had a kanackerd fan and corroded board, and the replacement is a good fan also with a corroded board. Now i have a knacked knob!!

[Mickey taker]

[quote="nige"]Now i have a knacked knob!!
There's some little blue tablets you can get from the internet that can help with that problem Nige,

Seriously though, if I can get to the shed this weekend I think I have a spare dash control panel and round turny things if you need them,I gave away a heater fan assembly at the cxm show

[mat_fenwick]

I assume the knob has split around the spindle, in which case it might be glueable. I'd put that on the RH spindle, as that usually requires the least effort to rotate it. The thread that Defender110 linked to shows how to get at the knob end of the cables - then you'll hopefully be able to see what is stopping the flap from working.

I have a spare dashboard end PCB if needed, which I modified so still works even if the earth to pin 3 has failed.

[Mothman]

If its just the knob, i have plenty of these, let me know and ile send you one.

Andy

[kiwi]

That knob/spindle problem. The previous owner of my TXD found a way of reairing that with a small metal ring. Not sure exactly what that thing he used is but being an Engineer he obviuosly enginnered something.

Am I also correct in assuming the Heater Flap problem refers to the one that controls heat? That would be the sticky dreaded Tap under the steering column. If its the one I m thinking of! But do you really want to do that job?