Hello all,
Could someone tell me which wires going to the a/c compressor are for the low speed and for high speed. There are 4 in all.
I'm trying to diag no signal to the compressor and would like to run a toggle switch for the mean time.
I know I'm bypassing wot switch and many others but this is only temporary. It's really HOT in Texas. Also who has the best sevice manual for this 90' 300D.
Thanks very much!

The compressor has no high-speed or low-speed. You probably have two wires for the clutch coil and two wires for a speed sensor.

ok thanks, I got the "two speed" wording from an retired mech who looked up some info for me on his all data. This system is still R12 and I initially took the car to him because I don't have R12 gauges, can't buy the freon and hoping it was just low on refrigerant.
I thought it seemed odd, the two spd. The system is full and will work if you exite the compressor but I still don't know why we aren't getting juice to the comp. via the control panel.
I'll search more for wiring diagrams online untill I get a manual. Thanks.

ac still not working after ac conversion 87 300SDL

Sixto
87 300D

There are three wires to the A/c compressor area.
Two for a speed sensor coil circuit(The dreaded KLIMA relay compares compressor speed to engine speed...too big a difference NO A/C.)
One to provide Positive power to the compressor clutch for engagement.

The link provided by SIXTO provides logical diagnostic steps.

#1. is blow up of compressor wires
#s 2+3 are a split of the complete schematic

Any one of the information sources (sensors,switches[gremlins]) can cause
the A/C control N6 to deny compressor engagement.
Much of this Folderol is to protect the belt that drives all the accessories.
(Think like a Mercedes engineer...No Belt...No Water Pump...Engine Overheat
Head Crack...No Fraulein in Leather Lederhosen for the Engineer.)

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'84 300SD sold
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