Could someone shed some light on this problem.The ac worked fine till last weekend but now no cold air and i noticed that the aux.fan will not even come on.Please let me know the causes and what and where to check
for the possible problem.
Thanks in advance.

You may have lost the pressure required to turn on the low pressure switch that arms the compressor.

Have a tech look at it.


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Benzmac:
Donnie Drummonds
1991 GMC Syclone
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

Thankyou Benzmac,
However the compressor appears to be running but the aux.fan inop and the rest is cool air not cold.

Thanks again for the advice.

Any advice would be appreciated

AV

If you keep your compressor working with no aux. fan, get ready to buy a new compressor. Do a couple of things:
1. Run a line from the battery to the aux. fan, be carefull. If it works, it is not the fan itself.
2. Check the freon pressure on ac system. If it is low on freon, you most likely, have a leak somewhere and that is causing the aux. fan not to work.
Did this happen all of the sudden?or was it a slow leak?
If not familiar with ac system, take it to a good MB mechanic as soon as possible.
Good luck
J.H.
86 300e

Check the fuse for the fan. Known to be faulty despite looking OK. If the compressor is running, then the pressure is at least high enough to close the low pressure switch, but it may not be adquate enough to achieve an adequate temperature drop across the condenser. Have the system pressures checked both low and high sides. You may also have a faulty expansion valve.


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Jeff Lawrence
1987 300e
1989 300e
1987 BMW 325

Thanks for the replies and is greatly appreciated.
Would someone please let me know where to find the aux.fan fuse on this vehicle.Its a 300E /1988

Thanks

Two 16 amp fuses in your fuse box under hood #D,#7 BTW don't over look the auxiliary fan preresistor,I have replace it a lot.

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MB STARS Master Guild Technician,12 years MB tech
6 years independent shop owner

Thanks MB Stars
Could you give me location on the preresistor if you dont mind.Fuses all ok.

AV

MB Stars,please let me know where the preresistor is and how to check.
Thanks in advance

AV

Within the engine compartment, left inner fender, rear of the headlamp assembly, in the immediate vicinity of the receiver/drier.

Use an ohm meter to check continuity and resistance.