AE111 BZG heater issue

[JT]

AE111 BZG

The aircon works fine through the whole heat range but with the aircon turned off the air coming out is warm/hot even on the coolest setting.

This happens when the fan is turned on. It also happens when the fan is off and fresh air setting is selected.
My wife got around the problem by using the air con or selecting re-circ when fan not needed.

Haven't had to fix a heater so I'm not sure where to start or what order to attack it.

Cheers

[MAC_HATER]

easiest check would be to see if the actual heater tap that opens\closes when you adjust the in cabin slider switch, and see if it is jamming or binding before fully closing, hopefully if should be accessible near the firewall in the engine bay

otherwise the other problem is the actual control unit in the dash, my one needed dry solder joints re-flowed, and even the tracks could be worn and not actually registering you wanting to close the loop for cold air, if you can track down a known good replacement to at least plug in and try and see if that also helps

[matt dunn]

Does it have climate control as the problems can be different for ones that do and dont.
By climate control I mean is there temperature numbers on the hot cold slide?

[JT]

Does it have climate control as the problems can be different for ones that do and dont.
By climate control I mean is there temperature numbers on the hot cold slide?

Yes it does have the numbers along the temp slide. How does that affect things?

[RobertC]

Try inspecting the back of the controllers circuit board. (needs removing and disassembling/) I have had problems with them in the past (fan speed changing on its own, heat not going hot cold as its supposed to)

There were a few dry soldier joints dry soldier joints on the circuit board, a few dabs of soldier and they were good as new.

Assuming your controller looks like this

[matt dunn]

Does it have climate control as the problems can be different for ones that do and dont.
By climate control I mean is there temperature numbers on the hot cold slide?

Yes it does have the numbers along the temp slide. How does that affect things?

Then the temperature is caluclated and so to get the temp part to work properly you need
the inside temp sensor,which is is a wee vent on the panel under the steering column,
and the outside temp sensor which is in front of the radiator

both must be connected for correct temp control otherwise the temp will be very erratic
and may not go hot, or not go cold.

[sergei]

I had similar issue in AE101 when the cabin temperature sensor got disconnected. only two temperature settings as effect of the fault: coldest setting would result in cold, and anything else in hot.
In AE101 the cabin temperature sensor is below the steering wheel (slighlty to the left) in the panel that also houses the bonnet release lever (opposite side of the sensor).