A/C cools and heats full blast; fan doesn`t turn off

[Geosteer]

Ran over a road hump recently with my 2000 2.0i Xsara heard some clicking behind the glove compartment, then the a/c went full blast, switched over to heating same full blast.
I suspect that the fan speed control, on/off switch , and the automatic temperature control all malfunctioned.
When the car was started for the run I heard intermittent clicking from the engine, turned off the a/c it went away, turned on a/c again it resumed, then as 1st stated the a/c fan control went dead on the way back.

Any similar experiences with solutions out there?

 

[George 1/8th]

Hey Geosteer...it sounds like when you went over the bump...something loose moved...like a washer or something..and has begun shorting some terminals..either around the relay wiring, or some switch wiring. It is possibly something in an inaccessable spot that someone dropped years ago and never bothered to pull out..and now it's causing you this problem.
Or a wire terminal is doing something similar. You will have to have a good look to find out what it is. It should be fairly obvious once you find it.
Cheers...George 1/8th.

 

[Geosteer]

Thanks George, here is the found solution:
Defective NPN transistor in climate control panel re symptoms re http://home.normgrills.net/bcg/Heat_&_AC_FAQ.html, which causes the blower control that is infinitely variable (not the 1, 2, 3, 4 position switches) to run on maximum only.

I got a junkyard replacement climate control panel at a grab & run 1/10 of Citroen’s price here in Brasil.

The Replacement:
-Place both hand into open pocket under the climate control panel one pressing up the other down and tug out the pocket and unscrew screws in view.
-Set gear stick to furthest position back
-Detach the gear stick casing from behind by reaching under, pulling out, then up (if automatic there is a screw to unfasten, next get your eyes to level and lift gear position indicator out of its carrying slot).
-Unscrew coin pocket/cigarette lighter panel.
-With flat screw driver pry out casing around radio deck, remove plastic radio deck face up to metal parts, unscrew at radio deck sides.
-Hold casing (that is around radio deck, climate control, open pocket) from the bottom and pry/wiggle it out working your way up. Hold back radio face with one hand while working the casing out to free the radio slut guide.
-Reach in behind casing and disconnect wires from climate control back (depress plastic spring lock at bottom and rotate the flat end point of a screw driver against the wire terminal side in order to pry out.)
- Place fingers on each side of casing free of climate control panel back & sides, with thumbs at front on right left regulators gently press in until the climate control panel pops out from the back of casing.
-Set mid-way the vent position regulator, extreme right of climate control, tilt climate control bottom towards you, locate 2 metal clips mid-way, disconnect out the 1st and free cable from slot, do same for inner cable.
-Now put in replacement climate control panel and work your way back to close up.

For the electronically inclined you may find it cheaper to locate and replace the NPN transistor board inside or detect which electronic component is reading bad and replace.
General Citroen a/c heater dismantling can be found at XM internet reference: http://xantia.rtkmail.ru/downloads/XM1.pdf

Easier steps to mine may be discovered along the way.

Sincere Thanks,
Geosteer, payzone@trini.com