Heater fan resistor

[daveblueozzie]

Now dont shout ,but ive just bought a brand new heater fan resistor
Ive soldered the old one about four times now,(and it had already been soldered before i bought it) and i think ive got to the end of its soldered life.
Ive checked that the fan runs freely each time, its a fan i bought from waycar which he had bought and fitted before his bongos untimely death last year, so i know it was in good condition.
what i need is a bit of info now from you techie guys and gals, is it worth taking the fan out and giving it a good overhaul (and what would be the things to look for and the ideal way to do it)
or will it be some other underlying problem causing the resistor to keep breaking. (or just my crappy soldering)
i dont want to fit the brand new unit for that to break.
so any info kindly appreciated.

[mikeonb4c]

I would take the opportunity to give the fan a good old overhaul and clean up. I wonder if it is possible to bench test it out of its housing by using a couple of extended wires. Then you could confirm it is changing speed promptly and freely as you change the dash switch from positions 1-4. It'd be annoying to blow a new resistor if a 'tight' fan is the problem (although it doesn't sound tight from your description).

[brorabongo]

I wonder.... Is your windscreen gully drain hole clear?

[missfixit70]

I'd agree with Mike, take it out, strip it down & lube it up, then do the fan motor
Even if it feels like it's spinning freely, it could be binding slightly on start upif it's got a bit gunked. If you look at the design of the air intake it's bound to get moisture in the motor. forward facing wide scoop, short inlet & the motor is below the level of the intake. May be an idea to add a drain hole, as several people have done, just like I didn't

[daveblueozzie]

thanks guys n gals ,it seems to be the consensus that its the fan motor causing the problem.


I wonder.... Is your windscreen gully drain hole clear?


you will hide brora

[davylaa]

Hi. I had same problem. I took the fan out and found that the brushes were gunked up and were actually stuck so not making contact with the spindle on the fan. Cleaned them up and works perfect now. Good luck.

[mikeonb4c]

Hi. I had same problem. I took the fan out and found that the brushes were gunked up and were actually stuck so not making contact with the spindle on the fan. Cleaned them up and works perfect now. Good luck.

Really ought to do mine sometime. Just for something to do! And actually it doesn't spin quite as freely as I would expect it to, though its' never given any trouble (but it must be slowly heading down the road all Bongo heater motors head down over their lives).

[rwill19050]

Also folks, when you start the fan running take it up to high speed first, then drop it down to your lower desired setting.
Gives it a chance to clear any residual 'sluggishness' (strange word that )
Reason:
When a motor starts it pulls high current until it is spinning, then the 'back EMF' kicks in and reduces the current flow though the windings.
The resistor controller is a crude device designed to 'waste' (in the form of heat, hence it is fitted into the ducting where the airflow can help dissipate it) some of the power available to the motor.
That's why it is soldered, too much current, too much heat, melted solder joint, open circuit, motor not burned out.
Blooming 'eck time I had a lay down in a dark room methinks

[waycar8]

got to agree, no harm in a little greasing , even thoe it looked like new Dave its been about 14 months now , it could well be starting to stick.

someone else not so long ago had the same problem with the resistor after they had soldered it, cant remeber who it was but no doubt a search will come up trumps, they might have found out why it kept blowing

[MattK]

It was me.......

And the cause of the problem was the fan motor.
It seemed to be turning freely, but I took it out of the bongo anyway to strip and lube it just because my resistor kept de-soldering itself. I Couldn't work out how to strip the fan motor so got a second hand unit.
It turned much more freely than the original and I haven't had the resistor blow since.

By the way, my resistor has also been re-soldered 4 or 5 times, and is still working no probs with the new fan.