Hi, We're having problems with our aircon. We know the fans sort of  work and there are no leaks in the low pressure side of the system. Does anyone know how to test an aircon evaporator fan? We think it has 2 speeds and are struggling to figure out the positive & negative wires. 

The fans will not cut in until the high side pressure reaches something like 15 bar, more in this hot weather, if the refrigerant level is low then the pump will not reach the threshold pressure.

We've taken it to a garage, and after several visits, we were told that the system won't regas as the fans won't come on.

23 minutes ago, ChicT said:

Does anyone know how to test an aircon evaporator fan? We think it has 2 speeds and are struggling to figure out the positive & negative wires. 

 

Best bet is to unplug the connector from the radiator thermoswitch and link contacts of that plug with a bit of wire. The incoming is the plain red wire, low speed outgoing wire is red/white, full speed is red/yellow. It's the condenser at the front of the car BTW, evaporator is the bit in the cabin. Ignition probably doesn't need to be on for low speed, but probably does for full speed, so may as well switch it on for all testing. Both fans should do the same.

 

Fan action via G65 refrigerant pressure sensor is 9 bar for low speed, 16 bar for full speed on models I'm familiar with, doubt there would be much variation.

1 hour ago, ChicT said:

We've taken it to a garage, and after several visits, we were told that the system won't regas as the fans won't come on.

 

The fans will not work on a system that needs regassing but non working fans do not prevent a system being regassed.

 

Try to find someone else with the gear and some idea!

 

Editted, I see you are in France so little chance of finding the above, I had your experience and some! Its what pushed me into getting my own AC test and recharging gear.

 

You look to be a couple of hours drive from me, otherwise I would help, is 41°c here today and will be the same tomorrow, not the time for a long drive without AC.

Edited 23 August, 20232 yr by J.R.