HI guys,
My fan control switch is playing up and the higher speeds no longer work, and the lower speeds only work when I jam something underneath the slider which pushes it up. Presumably this is not repairable and requires replacement?

Has anyone removed this switch before,which I assume comes out as an assembly with all four sliders? I have looked in the manual and it talks about removing the various cables from the back but I don't know how to do that when they can't even be seen. It also says to remove the heater control knobs and carefully pull out the heater control panel. What holds this panel in? There doesn't seem to be anywhere to pry it off and I don't want to destroy it. Any ideas?

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What line is your TM? (GLX, Executive, SE or Elite?) I've done this on my TP executive wagon but it was years ago, so I don't remember how I got the panel off. I do remember that when I finally got it off, I realised it could have been done a lot easier. I need to do the same on my TP sedan but have bigger problems to fix first. In fact, you may not need to take the panel off as the problem is usually not the switch but the resistor block.

Have a read of this thread: http://www.aussiemagna.com/forums/showthread.php?t=84737&highlight=resistor

It is a very common problem, so much so that you'll be hard pressed finding a working resistor block from a wreckers. The resistors are just coils of wire. They get very hot and they burn out. I replaced mine with 10 watt ceramic resistors but I don't remember the resistance values I used. They too get very hot. It is a very inefficient arrangement and when I get around to fixing this on my sedan, I intend to fit a variable speed DC motor controller like this: http://www.ebay.com.au/itm/130850777369?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

Coldamus,
It is just the GLX. I had seen other posts about the resistor block but I couldn't determine from the posts if it was relevant to the TM. I didn't notice the square block when I had the glovebox out today but will have a better look. I had assumed the control was a potentiometer arrangement.


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Yes, the resistor block is relevant to the TM and particularly the GLX and Executive. The Elite is different because it has the climate control system. I'm not sure about the SE but think it would be different too because of its "wing" controls. My first Magna was a TM GLX. I bought it new in 1987. It developed the same problem after a couple of years. The lowest fan speed fails first, then the second speed. Sometimes the third speed fails too but mine didn't. The fastest fan speed usually continues to work because it doesn't use a resistor but applies the full 12 volts to the motor.

Mine has failed in the opposite direction, from high to low. But I will locate and check the resistor pack first.

Tools

And if that checks out I might check the continuity of the switch before removing it.

Tools

And if that checks out I might check the continuity of the switch before removing it.

Good idea. Strange that high speed would fail first. That would almost have to be a switch problem.

Resistor block plugs into the ducting right beside the fan motor.
I have soldered my broken ones together on occasions and they have lasted. Basically the coiled wires corrode thru on them.
From memory you can pull the knobs off the three sliders but i think there are screws on the back of the dash that hold the fitting in place.
Will check later. Vee

Pulled the glove box down and removed the little black trim on the right that stops stuff falling down behind the heater controls and i could feel the phillips head screws that hold the controls to the back of the dash pad.
I have seen the back of it several times when taking out dashboards and only ever disconnected the cables from the lowers ends.
I am not sure if the front cover pops out or not once you have taken the knobs of the sliders. proceed with caution.
I would rule out the resistor block first. Vee

Be buggered if I could find the resistor block today. I just had another look in the manual and it doesn't appear to be as big as I had imagined. Is the block screwed on to the motor housing or does it plug in to it?

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If you look under the dash on the passenger side with the bottom trim/kick panel removed that has vents in it below the glovebox.
When you see the blower motor just to the right there is an oblong shape with wiring going to it there is one big fat wire that goes to the blower motor from it. Two phillips screws and it will pull down to remove. The coils on it are cooled by the airflow thru the ducting etc. Vee

Thanks veeone. I hadn't removed the bottom trim panel, just the glove box itself when I looked today I could see some wires going to the left of the motor but not the resistors. I shall remove the panel tomorrow and look again.

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Although I am yet to locate an check the resistors, I am leaning towards it being the switch because on the lower speeds I need to jam the switch up a little for the fan to run. I was near pick-a-part today so thought I would go in a get a switch. For $20 I now don't have to make a special trip to the wreckers which is more than two hours round trip. Turns out the fascia panel is just clipped in, and screws for the controls are on the front. The switch itself unscrews from the other controls so I will just replace that and not bugger around with the cable on the vent controls. I Will let you know how it goes!

Tools

Although I am yet to locate an check the resistors, I am leaning towards it being the switch because on the lower speeds I need to jam the switch up a little for the fan to run. I was near pick-a-part today so thought I would go in a get a switch. For $20 I now don't have to make a special trip to the wreckers which is more than two hours round trip. Turns out the fascia panel is just clipped in, and screws for the controls are on the front. The switch itself unscrews from the other controls so I will just replace that and not bugger around with the cable on the vent controls. I Will let you know how it goes!

Tools

Well I did find the resistor block and the small coil had a break at one end. I have soldered that back together and now have continuity throughout. The switch was buggered as well. When I opened it up there were scorch marks on the high speed contacts, and a couple of the wires from the switch had blackened slightly and had melted together. So all back together now and the fan works on all speeds, but it lacks power and runs slower than usual. Does the fan have brushes that can be replaced, or does anyone know what test I can do on the motor to see if it is buggered?

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Well I took the fan out today and opened it up for a look see. The whole motor was full of dust and fluff from the ventilation tube that blows air through it. One of the brushes was about 5mm long but the other had worn down completely and was non existent, the motor running with a spring providing power in to the commutator. I will source some replacements tomorrow from the tool shop and see how it goes.

Tools

Picked up some brushes today and after modifying them a little to fit I put the motor back together and it now works well on the bench. Tomorrow I will put it back in the car and touch wood with the switch,resistor block and fan fixed everything should work as it once did.


Tools

Back in and running but for some reason it doesnt seem tO be running on the lowest speed. Not too fussed really as I am happy to have it working on all other speeds now. It is slitly noisier thAn previously, not sure why. May have something to do with the type of brUshes that I put in, or the irregular wear on the commutator from one previous brush being non existent. It's not too bad though so not a show stopper

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