82 240D, a/c compressor kicks in with switch but air is only "cool" aux fan does not come on. I ran a wire to the fan and it works, pulled 1 wire off low pressure switch and compressor drops out. 1 of the relays under the hood is warm to the touch, swapped the 2 with each other, no change.

What turns on aux fan and how do I check it?
Should I see bubbles in receiver site glass?

Thanks, Mike

sounds like a normal 134a converted ac system.
John

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Your receiver/drier has two switches. One is for the compressor and the other is for the auxillary fan. I believe the one for the fan is the one near the top of the receiver/drier.

Scott

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Scott
1982 Mercedes 240D, 4 speed, 275,000
1988 Porsche 944 Turbo S (70,000)
1987 Porsche 911 Coupe 109,000 (sold)
1998 Mercedes E300 TurboDiesel 147,000 (sold)
1985 Mercedes 300D 227,000 (totaled by inattentive driver with no insurance!)
1997 Mercedes E300 Diesel 236,000 (sold)
1995 Ducati 900SS (sold)
1987 VW Jetta GLI 157,000 (sold)
1986 Camaro 125,000 (sold - P.O.S.)
1977 Corvette L82 125,000 (sold)
1965 Pontiac GTO 15,000 restored (sold)

i'm going to jumper the aux fan switch on r/d and see if the fan kicks on, thanks, mike

Just turn your ignition to "on" and then touch the two leads together and the fan should come on. If your switch is bad, simply unscrew it and put in a new one. You won't lose any freon when you remove it.

Scott

__________________
Scott
1982 Mercedes 240D, 4 speed, 275,000
1988 Porsche 944 Turbo S (70,000)
1987 Porsche 911 Coupe 109,000 (sold)
1998 Mercedes E300 TurboDiesel 147,000 (sold)
1985 Mercedes 300D 227,000 (totaled by inattentive driver with no insurance!)
1997 Mercedes E300 Diesel 236,000 (sold)
1995 Ducati 900SS (sold)
1987 VW Jetta GLI 157,000 (sold)
1986 Camaro 125,000 (sold - P.O.S.)
1977 Corvette L82 125,000 (sold)
1965 Pontiac GTO 15,000 restored (sold)

Jumpered it and fan comes on. Before I replace the switch I need to make sure I actually have freon in the system. There are no bubbles passing under the site glass, i see nothing moving, shouldn't I be able to see some activity?

I grounded the wire going to the temp sensor on the motor, should that have turned on the aux fan? it didn't.

You can always check the freon by using the poor man's method. Unscrew the plastic cap on your low pressure side line (the one right in front of you when you pop the hood). Get a flathead screwdriver and press in the valve and you should have ice cold freon shooting out. Just press it real quick. Make sure you are standing to the side - might want to wear gloves if you are extra cautious.

Scott

__________________
Scott
1982 Mercedes 240D, 4 speed, 275,000
1988 Porsche 944 Turbo S (70,000)
1987 Porsche 911 Coupe 109,000 (sold)
1998 Mercedes E300 TurboDiesel 147,000 (sold)
1985 Mercedes 300D 227,000 (totaled by inattentive driver with no insurance!)
1997 Mercedes E300 Diesel 236,000 (sold)
1995 Ducati 900SS (sold)
1987 VW Jetta GLI 157,000 (sold)
1986 Camaro 125,000 (sold - P.O.S.)
1977 Corvette L82 125,000 (sold)
1965 Pontiac GTO 15,000 restored (sold)

My Son has had my old truck, it laid down on him, got a wrecker to drag it home, looked through it and found a bottle of Crown. Haven't had a drink in months, just haven't wanted to, but there it is,,,,,,,,,,

I checked for freon on the low pressure side, 1 little weak, baby squirt. taking it tomorrow to have it refilled with freon and dye, more to follow. Mike