Xsara Heater stuck on full blast!

[Clogzz]

Very interesting !

Never seen a relay on my motor, but then I never took the pcb out.
It all makes very good sense.
The relay is for the maximum speed only, and the transistors are for the lower speeds.
Congratulations !

[Skull]

Bought a Xsara Coupe 2.0 HDi (2003) as a 'good runner' but so far it's spent more time in pieces ....

My blower was running full blast all the time and annoying me so decided to try and fix it.... electrics especially modern 'electrickery' are not my specialty

I was going to just wire in an on/off switch through the fuse box but that would mean drilling the bulkhead to run some 40 amp wire through ... then I thought maybe just take the control switch out and try and wire a switch into the live feed that way .... the dash is half out and I have removed the heating control unit .... bizarrely enough the fan still runs with the engine running even though the heating control unit is totally removed .....I thought there might be a type of rheostat in the unit controlling the speed of the fan that had failed I was expecting the fan to at least stop running when disconnected but now realise it's better as a fail-safe to have it running than have no demister at all .... clever guys @ Citroen

That's when I decided to have a look on here and from what I've read and the parts I think I've understood It sounds more like the resistors on the blower motor itself that may have failed

Can anyone confirm that this is the likeliest problem just from my description above

Apologies for meddling

[Paul-R]

Not the resistors but the transistors. My old Xsara did exactly the same thing (maximum speed - all or nothing - no adjustment on speed) and then failed completely. A transistor kit and some time with a soldering iron fixed it.

[Skull]

Thanks Paul-R I'll get the dash stuck back together and re-focus on the blower TRANSISTORS ....

[Paul-R]

Yes, I made the mistake of dismantling the heater control area first as well!