Failed interior heater blower

[KamperMan]

We have a 1983 DF water cooled engine. (done 130,000 miles!) For years the interior heater blower only worked on fan switch No 2 position. Now it doesn't blow at all. Is this likely to be a heater motor failure requiring a full strip out of the dash and replacement motor or could it be the variable speed resistor electrics? There is a good You-tube video of how to strip the dash off but I don't want to go to all that bother if it could be something much more simple! All ideas welcome.

[CovKid]

This is an electrical rather than mechanical question. The only way to know for sure is present the motor with 12v (bypassing resistor) and see if it spins. If it does you can rule it out and look elsewhere. Electrics fault tracing needs method rather than guesses so check the motor then work back.

You don't need to remove dash to check if motor works - although you have more room if you do.

[Ian Hulley]

You can bridge out the wires on the back of the fan switch to test if the switch itself has died ... that is a common fault and it costs nothing to check out and the switch itself is cheap to replace. Sadly the fan motors have 'form' as well and not only in T25s as the same unit also fails in Sciroccos and Golfs (the fan in our daughter's Jetta is starting to make all the wrong noises too)

Ian

[CovKid]

The one good thing about removing dash (and to be honest it doesn't take that long) is you get an opportunity to replace/rewire/refit items that haven't really been seen since the vehicle was built, and that includes washer pipes which by now will be furred up like a smokers arteries.

[nevill3]

When my blower stopped working this winter I stripped the blower switch down, I was trying to work out what had gone wrong when the blower started working if I pushed the switch in towards the dash. Take the switch out, it's really easy and it comes apart easily too, but do it on a table so you don't lose any bits. Mine was all covered in fine carbon like deposits, I cleaned it up and the heater blower works as it should now. An easy fix to try before stripping the dash.

[mrdp]

Hi, same as above fan only worked flat out or nothing push switch in and up and worked if you held pressure on it . The switch comes out and apart really easily and it's got to be worth checking before removeing the whole dash. I found the springs were getting snagged , worked them loose a bit and contact cleaned and worked fine ever since. Good luck.

[California Dreamin]

The problem is, a new switch is a 'Plaster' on a wound and not a fix. The extra resistance from the worn and partially seizing motor effectively overheating the switch and burning out it's contacts. Cleaning up the existing switch or fitting a new one appears to make everything work again but in reality the high resistance/high current draw still remains meaning inevitable blower motor failure isn't too far off in the future.

Martin

[CovKid]

Would agree and any child who ever played with a micro DC motor and consistently stopped it from going round with their hand will vouch for how rapidly the motor weakened and then required a hand-spin to get it going again. Most are around 30 years old now, even 20 years is good going for a motor like that. If the motor isn't completely dead it will certainly draw more current on start up than a new one would. The fuses just get bigger over time, and the switch more clogged. Cleaning switch or 'oiling' motor WILL often get the motor running again but its no way a cure - merely an extra couple of years for a terminal patient. In the end, its better to just get in there and do the job rather than fettle with it.

To be honest, if I were going to strip dash I'd be doing the wiper motor too. Who wants to do jobs like that twice? The price of both motors combined is only marginally over £60.

[_colin_]

Hello all!

I've just bought another T25 after a 5 year hiatus and am getting quite a few easy fixes done. Next on the list is the heater, I have noticed the heater switch is missing completely and I can't see any wiring.

I was just wondering if anybody could help me by having a look at theirs and let me know which colour wires etc I should be looking for!!

Thanks in advance!

Colin.