A little help with this A/C relay for aux fan operation? - PeachParts Mercedes-Benz Forum

RANDY P · #11 04-13-2012, 12:12 AM

Quote:

Originally Posted by ah-kay

How competent are you with auto electric? There are simple hacks and there are better hacks.

1) Simple hack -Wire a toggle switch into the cabin to jump/connect the high pressure switch on the rec/drier. Toggle it when A/C is on. This will turn on the aux fan at slow speed thru the R14 ( may be R15, cannot remember ).

2) Another hack - Wire a toggle switch into the cabin to jump/connect 1 pin of the thermostat on the engine block to ground. Toggle it when A/C is on. This will turn on the aux fan at full speed.

3) Good hack - Splice into the compressor wiring or Kilma pin 7 to get a switched 12v. Then wire up what compu_85 drew. I also posted it earlier.

Good luck.

Amazing. Like this is an acceptable solution? /\/\/\ Put a hole in the dash with a toggle switch?

How elegant

Another dash ruined by backyard butchery.

How about giving the system enough pressure to register it needs to have the AUX fans on? Like it's supposed to?

To the OP. Spend a few bucks and increase the system pressure to the high side of spec- then go from there.

rjp

BTW "jumping" the high pressure switch on the reciever dryer also involves bypassing the pressure cutoff- you know that switch that registers when the system high side pressure exceeds 28 BAR it cuts off the compressor..Does the same when pressure drops below 2 BAR..

Its a safety feature.

Fiddling with that is a good way to blow your car to bits.