Xantia heater only blowing cold????

[gadgetgricey]

Ok, it does not take much, but getting really confused.

Currently undergoing battle with the Xantia to get its blower working. ( See other thread ), tested the motor by applying a direct feed to it and it sprung into life.

Going away for a week so thought as a short term measure would leave it like this ( with a cut off switch) so can just have the heater on full when needed and disconnect when not.

Great plan.... Went out for a thirty min drive tonight to take daughter to her band practise and the fan never got warm/hot???? Just blowing cold air at full speed constantly. Daughter was not impressed.

Now I have changed the slider mechanism previously as the first thing when trying to fix the blower, but the other cables adjust fine. Direct the air flow and recirculation, but cannot get warm air.

There is resistance in the heat control, so I think it's connected correctly, but am I missing something?

Does the cars electrics know that the heater is on bypass, and an electric flap motor somewhere is not functioning, hence no change in temp.

Any advise as always greatly appreciated.

Many Thanks

- Dave -

[rory_perrett]

On the exclusive (and possibly others) the temperature is controlled by the ECU via a motorised flap. When I had my problem with the feed to the blower motor relay, the fan did not work, neither did the AC nor the flaps, so no hot air.

If you press the aircon button does the light on the switch illuminate to show that it is on?
Does the aircon come on? Do the rad fans come on?

The system might not know that the (assume you mean blower) is bypassed but as the original problem was the blower not running (ie the system not switching it on) then the lack of hot air could be related to the original fault. Or you could of just picked up another one - don't you just love Xantia electrics.

Just thought, as you have bypassed the control module on the blower, there is no feed back from the fan module to the ECU (via the other two wires on the 4 way brown plug) so I guess the ecu hasn't a clue what's going on and so may behave in an unpredictable way. I would probably focus on getting the blower working in the "normal" way and then investigate the heat problem if it is still there.

Rory

[Mandrake]

The temperature slider control is just an electrical input to the climate control ECU which then uses that plus information on the ambient air temperature, outside air temperature and so on to operate the mixer flap motor. If the ECU is not working the mixer flap will just sit in whatever position it was last sitting in - apparently in this case cold.

If you know someone nearby with a Lexia the climate control ECU can be communicated with and diagnosed using the Lexia - it will show a full set of live input data like the temperature slider position, fan speed slider, air output position (face, feet, windscreen etc) as well as temperature sensor readings for the cabin air temperature, mixer flap air temperature, evaporator temperature and outside air temperature.

It can also perform actuator tests such as operating the mixer flap through its full operating range from cold to hot, forcing the fan to run, forcing the air conditioning to turn on etc...

That would be your best bet to identify what is going on without a lot of trial and error.