Auxiliary radiator air con fans

[RayHeath]

I have two auxiliary fans in front of the radiator which come on for added air flow when air con is requested at slow vehicle speed. I have just had my air con recharged and the specialist noticed that the air con fans did not come on until the gas was at a rather high pressure. When they did come on it was only for about five seconds before switching off. He said that the fans should have two stages. Stage 1 is when the vehicle is going at slow speed e.g. stationary. Stage 2 is when the coolant reaches a set point. The fans on my R129 500SL 1992 only come on for stage 2 apparantly. He suggested the problem could be solved by an automotive electrical engineer as he didn't deal with fans, only the gas side of air con systems. What needs to be fixed and can I do it?

Ray

 

[guydewdney]

http://www.continentalimports.com/ser_ic40142.html

should identify the prob if you have this type of control...

guy

 

[Mr Fridge]

When the pressure is high, is the liquid line or filter drier hot ? If not hot you have non condensables in the system such as air, quite common if the system was not completely discharged of gas and evacuated prior to recharging, also over charging of the system can have the same effect, high pressure, cool liquid line.

 

[Andy]

Hi

I not sure that I agree with your specialist AC recharger. The fans should come on for two reasons. Either the pressure in the AC system is two high or the engine tempreture is too high. If the AC is working ok. Then don't worry too much. Check if the fans come when the engine gets hot especially now where coming up to summer.


Regards


Andy@ www.mercedesservicing.com