Xantia Heater Blower - fault found -some info !

[Nigel Darwell]

Firstly guys thanks for all your help, in the spirit of co-operation I have documented my findings in the hope it may save others some of the time and expense I have wasted.
Firstly the Haynes manual which covers the MKI Xantia has post 1998 wiring diagrams which are generally accurate regarding the heater blower circuit, although doesn’t detail the climate control. Secondly the ignition barrel switch on the Xantia is dfifferent to any I’ve seen before in that of the six wires four act in a ‘normal’ way i.e. main feed in; switch position 1 out; switch position 2 out; and start. The other two red ones are not connected to the others in any way, they are purely a set of contacts (used as the blower feed switch on Xantia MKI, and prone to burning out)
The Xantia II has a relay (drivers foot well) to overcome this problem. The blower circuit is as follows: The large max fuse B in the engine bay supplies power via a 40a fuse to a white cable which runs to fuse 21 and then via the blower relay to the blower motor. A spur from this white cable goes to the pair of contacts on the ignition switch (two red wires and a brown connector, as mentioned above) once switched a small cable then feeds fuse 5 which in turn powers the climate control regulator and the switching coil of the heated rear screen relay.
In my case this main feed from fuse B ( the white cable) had a poor feed, resulting in low volts at the blower motor and an unreliable feed to the climate control and heated rear screen switching circuit. I have temporarily resolved this by introducing a new feed, I suspect the route the feed cable takes is across the front of the engine bay and through the bulkhead somewhere near the accelerator pedal, which means its behind the wheel arch liner (a good place for anything electric !!) I suspect there will be a bulkhead connector there and its that connection which has burn out / corroded. I will investigate further in the fullness of time !
So if you have blower problems and intermittent or no HRS and climate control problems (no or intermittent temp control) probably worth checking the above route.
My Xantia is a 1999 face-lifted MK2 Hdi.