Xantia 2.0 HDi Heater Blower

dougm · Post by **dougm** » 27 Dec 2006, 13:57

Heater blower has failed, but runs on direct connction to battery. No power at brown plug connected to blower. HRS works OK. In recent down pour blower came on and all came on inc aircon whch fails with blower. All fuses and relays appear Ok, but any hidden ones?Booked in to local Cit dealer for diagnostic help on advice of auto electrician who couldn't cure.Heat through ram effect but sometimes even this doesn't work. HELP please. Auto electrician found control box but there was no output to blower from it.

Clogzz · Post by **Clogzz** » 27 Dec 2006, 14:32

Do we mean no power coming from the brown plug at the ignition switch ?
Then it’s the switch that’s faulty.
What vintage is the car ?
From about 1998 or 99 there is a factory modification with a relay to operate the blower.
The rear screen demister won’t work if the blower drags down all the voltage at the ignition switch.
If there’s some useable voltage left there, it may be enough to operate the rear demister timer, which is a relay.
The current for the demister heating element doesn’t pass through the ignition switch.

Modification here: http://www.frenchcarforum.co.uk/forum/v ... hp?t=17322

Drawing by RichardW: http://www.geocities.com/tricky992002/fanmod.xls

dougm · Post by **dougm** » 27 Dec 2006, 17:05

Thanx for info. car registered Nov 1999. The brown plug connects to the blower with 2 hefty wires, brown and black, and two other smaller gauge which all plug into the blower.

Clogzz · Post by **Clogzz** » 28 Dec 2006, 15:13

November 1999 is after the introduction of the modification.
Hope that the registration date isn’t too far behind the manufacturing date.
The thin wires are the output of the control box.
The control box is prone to dry joints, and may need resoldering in places.
A test lamp on the thick brown wire (usually red) will indicate if the voltage is high enough with the blower plugged in and switched on.
The thick black earth wire can also go dodgy, but since the blower works straight from the battery, we can assume that the earth is good.

dougm · Post by **dougm** » 24 Jan 2007, 16:24

Thanx for the advice. Had to get it diagnosed at the Cit dealer who said it was a faulty fuse board. had it changed and it all works OK now. got the old one to pieces but nothing obvious wrong with it, seems nothing to go wrong, so another brick in the wall! Thanx again.