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Discussion Starter · #1 ·
Mondeo Mk3, faclift Tdci, heater will not put out hot air.

I run the diagnostics and I get error code A3 08.

This isn't on the list in the Wiki nearest code is B2308 Interior temperature sensor for the fan Damaged motor or open circuit motor inoperative.

Does these mean I have a fault with the fan motor or its control. If I disconnec the fan and/or the control unit then I still get ht esmae error code.

I have ordered a fan unit with a control unit to swap out and see it it cures the problem.
 

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its the small interior temp sensor with a small fan on the RH lower dash facia. 6 screws (2 behind small glovebox) remove, replace sensor, refit...
 
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Discussion Starter · #3 ·
its the small interior temp sensor with a small fan on the RH lower dash facia. 6 screws (2 behind small glovebox) remove, replace sensor, refit...
Thanks for the info.

I thought this sensor was Ok because I disconnected it and got another fault code (9251)

Reconnected it and fault cleared. Looks like the sensor is Ok but the motor/fan is faulty.

I'll have to search ebay for a replacement. Already bought a Blower fan and controll, don't need it now but it was only £20.
 

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May sound silly but have you checked your rad water level as if it's to low you won't get any heat coming out either, had it on a company rover years ago!!
 

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Discussion Starter · #5 ·
I have replaced the sensor behind the lower trim panel (twice in case the first replacemnt ws also faulty).

Still got the fault code with all 3, A308.

Next I replaced the control panel, The one I got must be from a facelift LX. So this one doesn't do climate control but hat means I dont need a working sensor. I put this one in. No fault codes but I still dont get any hot air.

Hence I must have another problem.

I have removed the heater flap motor and checked the flap is free to move (It moves easily).

With the motor out and the engine hot I moved the flap to each and and I still don't get hot air (not even warm)

Is there another flap for hot air as well???

My next step is to check the matrix is getting hot - although I haven't had any coolant problems.

Is ther anything else I can check???
 

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Discussion Starter · #7 ·
I now have finally got hot air from the heater.

it turns out I had 2 faults

1.fan on the cabin temerature sensor not running, Replacing the sensor still gave the same fault code. I replaced the control unit with one form an LX so it doesn't need the sensor. No fault code but still no heat.

2. When I replaced the steering rack a few months ago I trapped and kinked one of the hoses preventing water flow to heater. Sorted it out and I now I have hot air!

Looks like my original control unit (climate control version) is either faulty or the re isa wiring fault. I checked for an output to the sensor motor, even with an oscilloscope there was nothing.
 

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Glad you've got warm toes again. One to remember. Will you go back to climate control do you think?
 

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Discussion Starter · #9 ·
Glad you've got warm toes again. One to remember. Will you go back to climate control do you think?
I think my climate control unit has a fault. I get fault code A308 when I did the diagnostics. The fault codes area bit confusing, I havn't actually seen a list that shows A308 but --08 appears to be the fan for the sensor.

With the LX version (not climate control) I dont get a fault code, it doesn't use the sensor.

I have 3 cabin sensors, whilst its possible they are all faulty it seems unlikely.

I checked the output to the sensor fan motor and I dont see anything even with an Oscilloscope so I suspec the control unit.

I can work out what type of motor is used for the fan. I would have thought its is just a straight forward 12v dc motor, but not sure. It could be a stepper moor!
 
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