Heater Blower again

[Dodgey]

After fixing a water logged motor a few weeks ago, once again it failed. Though this time more seriously.

I noticed a strong smell of burning electrics the other day, which then passed. I could not figure out what it was until yesterday when I tried to switch the fan on!

Not only does the fan not work in any position, but if you switch the AC on it lights up (and you can hear the compressor engage) on fan settings 2 and 3 only, nothing on 1 and 4. What does this suggest? I have a horrible feeling I've toasted the motor and perhaps the resistor pack.

[ginger colin]

Hi. the aircon light (system) will not come on without the blower running (or selected to 1) . I think its the same for the rear cab heater fan as well.

I use servisol super 10 switch cleaner in motors... its should flush any pieces out that may be restricting the motor.
also check the intake in the grill (it could be full of leaves/crud). You can remove it by removing the plastic scrivets and clean it out. It pretty tough so a medium brush is suitable.

[Dodgey]

I checked and it's (the AC) actually not coming on on only setting-4 (and off, of course). So the AC comes on on 1,2 and 3.

I'm guessing my motor seized and it's burnt through the link for "4" on the resistor block. Hence AC doesn't come on on 4, but it does with 1 2 and 3.

I'll strip it when the weather improves...

[Dodgey]

Got it all stripped out today. The fan was seized - no surprise - the amount of water that is getting in the bottom of the motor housing is shocking. There are rusty tide marks over all of the inside of the plastic lower housing. I've drilled three small holes in the bottom of the housing to let future water out.

I'm bemused as to where the water is getting in. Even if the gutter drain hole is blocked (which it isn't) the water sill should not be able to get into the fan. The only way I can see is through the air intake, but that's protected by the bonnet - mostly. I assume rain as I drive is cumulatively getting through the intake, and then pooling in the motor hosing.

When I drilled the three small holes I notices there was an exiting blocked hole so I assume this is the root of the problems.

I'm about to test the resistor pack - any one know the ohm readings and pin config? I'll take it apart to work it out but it would be nice to know.

[jimmo62]

If you have climate control (not the manual controls) then the "resistor pack" is actually a transistor controlled by the Aircon ECU. If the fan only runs on MAX then it's likely this is broken because on max it is bypassed by a relay. Its plugged into connector G3-04 on this wiring diagram http://www.g8dhe.net/bwm/bwmanualp.htm?1995/Page_84

You may find the dealers call this a resistor pack in their parts lists as it does the same job as the resistor pack - but you will probably not be able to test by measuring (although if you have a continuity tester you could try between base and emitter and base and collector - in each case you should get continuity one way round but not the other) - base being the lead connected to pin 2D on the ECU

[Dodgey]

Thanks Jimmy - I've got it all sorted now (I have the traditional resistor pack, that was blown in 2 places).

So what happened is this.... my fan suffered from water ingress for the 3rd time. The 1st 2 times the motor electrical internals got rusty and wet and just didn't work. I cleaned them up, and it was fine. The 3rd time, the motor seized on the bottom bushing with rust. This caused the motor to stop with the brushes in contact and then burnt out 2 tabs on the resistor pack.

The resistor pack is easy to take apart, you just bend the little pins inwards and then remove the bakalite black bit and you can see all the soldered tabs. 2 of mine had gone and I simply resoldered them. Why the fan fuse never blew god only knows.... I measures the resistance across various pin configs (once re-soldered) and got between 1 and 4.5 ohms.

At this stage I cleaned up the motor, again, and cleaned and realigned the bottom bushing (it moved to an angle in it's plastic mounting) and re-greased it. I greased all the brush areas too. It now spins freely. I then reassembled the motor and ran a smear of silicone around where the base metal can meets the motor can to waterproof it.

I then went about figuring why it kept getting wet. The drain hole in the bodywork above was clear. I tested it by pouring water in the gulley fast. The hole coped, but I can see how it would not have in very heavy rain, and how hail would have certainly blocked it for a short while. We've had a LOT of rain and hail in Somerset.... as we have everywhere really!

I then wondered how water was getting in the motor cowling. The piece of black plastic that screws into the base of the motor. This is the problem area. Water has been collecting in there and filling up - the rusty tide marks showed this. It has been filling up enough that the 2 screws holding the motor end cap on had rusted so badly that I had to use mole grips to remove them. These screws I used with no problems only a month or so ago.....

So the motor end has been sitting in water - hence the bushing rusting up. I decided to add drain holes....



I never noticed an existing drain hole, but the central one I drilled went through as if there was already a blocked hole there. So I assumed there was. I added 2 more.

To be honest, the fan would be altogether better off without this plastic cowling. It's the cause of the motor sitting in water. But as it came with the car I decided to keep it.

I then looked for how on earth water was getting to it as it sure as hell wasn't coming via the fan opening. Dry as a bone and no signs of rust at all. But then I noticed, the bottom cowling has a raised edge that runs round part of the fan housing, sticking out - a perfect water trap.....

So I ran a bead of silicone sealant around it...



I'm betting I won't get any further problems...