Berlingo 2.0 HDi Heater fan not working

[jardinvert]

Hi - any advice on how to get the heater fan working on a 2.0 HDi Multispace with a/c.

Have reviewed many posts suggesting that the semiconductors may be faulty but appears this rectifies the problem with the heater fan constantly on full power. Also read that it may be an issue with the fan resistor pack - haven't managed to locate this as yet anyone know where this is - since there is no activity from the fan on any setting.

I've taken the motor out and the relay on the circuit board switches when the fan speed controller is on set to maximum in either direction.

Has anyone had a similar issue that they were able to resolve?

Many thanks,



David

[Peter.N.]

If its the same blower assembly as in the Xantia/XM it has a pair of transistors which act as a speed regulator, this is controlled by the input voltage from the control panel, if the transistors go leaky or short circuit this can have the effect of switching the motor full on.

Looking at the top end of the motor or maybe through the side, you should be able to see a metal heat sink with two transistors on it, to get to it you need to remove the motor from the casing which if I remember correctly you do by pressing in the three rubber blocks in the frame.

Peter

[jardinvert]

Peter

Thanks for your advice - I've dismantled the motor and separated the controller unit with the two transistors from the housing and noted that the relay works - gather this bypasses the transistors when on full power - however the motor will not function on any setting even though power is getting to the relay so I'm now wondering if it is the transistors.

I'd read on a different posting that the Heater Resistor Pack can fail and a quick search revealed another control unit sited elsewhere than the motor/housing. Perhaps it is this that needs fixing but I'm not able to locate it's position in the vehicle - understand it is somewhere behind the fascia.

Has anyone had a similar experience?

Thanks,




David

[Peter.N.]

Hi David

Have you tried applying power directly to the motor, I have never known one go faulty but there is always a first time. I take it that there is 12 volts present across the two thick leads the feed the motor assembly. I can't remember whether it is a permanant magnet motor or not, if it is applying 12 v directly to the brushes should make it work, if its got field coils one end will be connected to one of the brushes and the other end and the other brush are where you feed the power in.

I don't think it has a resistor pack, the function of that is carried out by the transistor regulator unless it just has a very low current one to energise the transistors. The feed from the speed controller is fed via the thin wire that goes to the module, if you earth it this should switch the transistors hard on.

Peter