The Dispatch | Expert | Scudo Hub

Hi All,

I just fixed this on my van. Turned out to be a stuck carbon brush in the fan motor. If I had tried to replace the "resistor", I would now be £21 down and still no fix. I do recommend a methodical approach to fault finding. I cleaned my slider contacts first because they're easy to get at. No joy. I then removed the blower motor. I pulled the spade terminals that connect the "resistor" to the brushes and connected the brushes directly to 12 volts. That should have made it run at full speed but it didn't so I knew that the motor itself had a problem. After sorting that out, I tried it again and the motor ran. Next I tried it with the "resistor" in circuit and it all worked. Hooray!
If it hadn't I would have checked that the voltages on the 4 pin connector were doing what they should before I ordered a new "resistor".

Ricko or anyone needing to clean the sliders,

Take plenty of photos as you go for reference later.
Your long term fix is to pull the 3 knobs from the sliders
Lever off the gear stick gaiter from the dash.
Remove screws holding the ashtray and then lever that off.
Remove screw holding the heater control panel and then lever that off.
It may now help to remove the connector blocks from the back of the hazard warning light switch and any others.
The sliders are now sticking up through a electrical circuit board. Remove the 5 screws that hold this down and carefully lift it out. There is an electrical connector on the back of the board that will need to be released by moving the locking lever then pulling the connector block off.
The fan speed slider and the temperature slider both have a little brass contact springy things around their bases. Gently lift them both off.
Take your brass contacts and the circuit board to your workbench/kitchen table.
Clean the dusty side of the circuit board with a small paint brush and vacuum cleaner. (Don't suck the brass contacts up the vacuum.)
Wipe any grease off the other side of the board with a rag and paraffin or white spirit.
On the underside of the circuit board for each slider there is a copper contact strip on each side of the slot. One side is continuous, the other is segmented. Polish all 4 up with a fine abrasive, say 400 or 600 grade wet and dry paper.
Also polish the little wipers on each brass contact that will make contact with the strips on the circuit board. If the wipers have become flattened give them a little tweak so that they will stand up an make good contact.
Clean it all again to get rid of any abrasive and dust.
Put a light smear of petroleum jelly on the contact strips and you're ready to reassemble.

Reassembly is simply the reverse of disassembly. When replacing the top heater control panel cover, there are strips of rubber dust excluder in each  slider slot. it is easy to push these up into the slot and jam the sliders. A thin spatula can help to work these down. Something like an artist's palette knife or an old fashioned bone handled butter knife. The knobs for the sliders have a slot on each side of the shaft which is a little tricky to get properly aligned with a pair of ridges on the sliders. When it engages properly the sliders will move freely.