Auxillary cold weather heater fault ?

[HDI]

My Xantia is fitted with the Webasto cold weather auxillary heater and this has worked fine since I bought the car. However , looks like it's decided not to work now ! Does anyone know how it's activated so I can start fault finding ?

[DickieG]

Its turned on in one of two ways, originally it was done by the engine ECU, whatever the weather it would always be fired up then turned off by the ECU when the engine temperature reached 80° C. However as that was rather wasteful Citroën published an Info Rapid whereby the operation of the heater is now controlled by installing an additional temperature sensor by splicing into the loom running to heater control relay located within the under-bonnet fusebox to prevent the heater operating under 5°C. The relay is located towards the centre of the car or as you look at them from the front of the car the far left one, look for additional connections underneath it to work out what version your car has.

If you have the original version still fitted, you can force the heater into operation by removing the lid from the relay then closing the contacts (insert a small screwdriver behind the contact to force it shut) then start the engine whereupon you should hear the heater start to briefly purge for a minute or two before it fires up.

If that didn't work remove the heater unit (remove/pull back the N/SF bumper and wheel arch liner) to gain access then turn it upside down in case it has filled with diesel so that it drains out via the exhaust. If that's the case having drained it you might be lucky in that the heater will now run OK (test it as above before refitting).

If that still didn't get it working it may well be that the glowplug is U/S, remove the lid etc to gain access. Glowplugs can be bought from GSF of about £15ish IIRC.

BTW I take it you have checked the fuse?

[DickieG]

I've found a good link that explains how the heater works here

BTW the heater is not a Webasto, its a Eberspacher D3W which is a variation on the ones fitted to VW T4 vans and Sharans/Galaxy's.

Here's some photo's of the one fitted to mine