Technical Air conditioning fan always on

[MKUser]

Hi, it's now some months my air conditioning doesn't work.
I pressed the button and the fan started but no cool air.
I suppose I've lost the gas and I have to put it again if there's not a leak somewhere or other issue.

Yes I assume not having air conditioning but, it's now a few days , when I put contact key on,even without starting the engine, the fan is always on.
The button doesn't work and the orange led on it doesn't light.
I've had the retire the fuse of the air conditioning to stop the fan.
Any idea of what can be happening ?
Ducato 2.8 jtd year 2003.

 

[Eternal Optimist]

I suspect you'd be best advised to take the van to an air-con specialist who can check/detect any leaks or failures in the system.

 

[Communicator]

I am always sceptical when relays are suspected as the cause of a fault, with no supporting evidence. However the heater fan is one of the larger electrical loads in the vehicle. The ignition on control is made via red coloured relay T12, in LHS cab fusebox, B002. If the contacts of this relay have welded together, or grown a whisker, the fan would run as described if the speed switch was not at "0".
I am aware of at least one reported problem with T12.

The fan should still turn off via the speed control switch. If this is not so, then something is very wrong.
Turn speed control to "0", and replace F55. Speed control should work.
Remove fuse F31, at top LHS corner of fusebox B002. This will remove ignition control from relay T12, which controls the fan supply.
Fan should not run if speed switch moved from "0". If fan does run, then relay T12 has possible welded contacts.
Replace relay T12, with relay removed from adjacent T01 position,or a spare relay. Again fan should not run if speed switch moved from "0".
If fan does not run, replace F31. Check that fan does not work.
Turn on ignition key on, and check for normal operation. If fan operates as normal, then test the large pins (30 & 87) on the relay previously removed from T12 position for short circuit.

I am attaching my diagram of LHS cab fusebox B002. This is slightly customised, but will serve for component location. Also attached is a corrected copy of eLearn diagram E6010 for the basic heater fan control without air conditioning, but it should be OK for to help understand the tests detailed above. I do not have a fully corrected copy of E6020 for fan control with air conditioning.

 

[Communicator]

I suspect you'd be best advised to take the van to an air-con specialist who can check/detect any leaks or failures in the system.

Please live up to your Nom de plume!

 

[Eternal Optimist]

Please live up to your Nom de plume!

I can only speak from my own (albeit limited) experience when I had similar problems. A mechanic friend suggested the above advice as it should keep the ECU happy. As you know, strange things can happen when the ECU doesn't like what's happening.

In this case the vehicle was a Vauxhall Meriva which belted out heat when the air-con button was selected. The actual fault was the condenser mounted low pressure switch. I changed the switch and the problem was solved.

 

[MKUser]

I suspect you'd be best advised to take the van to an air-con specialist who can check/detect any leaks or failures in the system.

I am always sceptical when relays are suspected as the cause of a fault, with no supporting evidence. However the heater fan is one of the larger electrical loads in the vehicle. The ignition on control is made via red coloured relay T12, in LHS cab fusebox, B002. If the contacts of this relay have welded together, or grown a whisker, the fan would run as described if the speed switch was not at "0".
I am aware of at least one reported problem with T12.

The fan should still turn off via the speed control switch. If this is not so, then something is very wrong.
Turn speed control to "0", and replace F55. Speed control should work.
Remove fuse F31, at top LHS corner of fusebox B002. This will remove ignition control from relay T12, which controls the fan supply.
Fan should not run if speed switch moved from "0". If fan does run, then relay T12 has possible welded contacts.
Replace relay T12, with relay removed from adjacent T01 position,or a spare relay. Again fan should not run if speed switch moved from "0".
If fan does not run, replace F31. Check that fan does not work.
Turn on ignition key on, and check for normal operation. If fan operates as normal, then test the large pins (30 & 87) on the relay previously removed from T12 position for short circuit.

I am attaching my diagram of LHS cab fusebox B002. This is slightly customised, but will serve for component location. Also attached is a corrected copy of eLearn diagram E6010 for the basic heater fan control without air conditioning, but it should be OK for to help understand the tests detailed above. I do not have a fully corrected copy of E6020 for fan control with air conditioning.

Thanks a lot but my problem is not the heater fan but the air conditoning fan that remains on always , the button doesn't work.
I've had to retire the fuse to stop it.

 

[Communicator]

Thanks a lot but my problem is not the heater fan but the air conditoning fan that remains on always , the button doesn't work.
I've had to retire the fuse to stop it.

Obviously a communication failure! Please state whether it is the fan inside the cab that is the problem, or an engine cooling fan. Precisely which fuse have you removed?

 

[MKUser]

Obviously a communication failure! Please state whether it is the fan inside the cab that is the problem, or an engine cooling fan. Precisely which fuse have you removed?

Hi, thanks for your answer.
The fuse is the F55.
The clear green one ( 30A) we see in the picture.
The thing is if I put contact key and don't touch the air conditoning switch, everything is correct.
Once I press the switch one time , the cabin air conditioning starts and after that it doesn't matter the times I press again the switch, the fan never gets off.
One thing I've noticed is the orange led on the switch lights on and off, like it works normally.
If I turn off the contact key, all gets off.
Turning on again the contact key, everything begins again.
All normal while I don't press the air conditioning switch.
Another thing is the air conditioning compressor doesn't work when I press the button, only the cabin fan.