Intermittent front heater fan

[rossdg]

Hi all - I'm scratching my head so ANY help would be welcome! My Bongo has digital "Climate control", 1997. The front fan stopped blowing, but rear is fine. Found that fan was stcuck, rather than seized, turned by hand and worked fine. Started the van next day and smoke blows in through vents...fan stuck again. Removed, cleaned and lubed, spins freely by hand, spins no problem with direct 12v supply. 12v is being delivered to the loom connector for the fan, and fuses all look good, but fan does not spin (rear heater fan works great at all speeds). Disconnected again, fan runs great on direct 12v supply, and there is 12v at the loom connector. I'm stumped, any ideas?

Thanks in hope......

[g8dhe]

You say smoke blew through after the first repair attempt ? I wonder if you have a damaged/burnt commutator (the copper plates that the brushes touch to pass the current through to the coils) which it is stopping on and won't then start on the next occasion, might be worth carefully turning it the motor by hand and seeing if there is a rough spot or remove and inspect the actual commutator itself. It might be sufficient to clean them if they are dirty otherwise its a replacement job

[rossdg]

Thanks, done that - no joy. Spins up no problem with direct 12v from battery - so don't think thats the issue.

[g8dhe]

Have you tried all the Fan speeds ? The lower speeds are controlled by a transistor, but the highest speed is by a relay bypassing the transistor, if it works on the highest speed but not on the lower ones then it indicates that the transistor is blown, they are replaceable.

You will see +12 volts on the motor the transistor is on the ground side;

[rossdg]

Tried all speeds, nothing, but I suppose the tranny module could fail completely? Sorry to ask, where is it located (guessing in box above aircon cooler against bulkhead)?

[g8dhe]

Yes its fitted where the older type of resistor pack is located, but if its not working on the highest speed then the transistor is out of the equation. Might be worth checking the grounding however at Earth point 1 - click the Blue earth circle in the diagram above and it will show you the location, under the front bonnet near the horn. Otherwise use a meter and follow the +12 volts, if its present on both sides of the motor connections then it implies its an earth fault, so check back at the relay G3-05 (Bonnet nearside above wheel arch) and then down to earth at the point above. My guess will be the earth point needs a bot of a clean up.

[rossdg]

Cheers, will check tonight if the rain stops long enough!

[g8dhe]

Only to be followed by Snow it seems Better get that heater working