Driving at speed my AC compressor/clutch cycles on and off every 20 - 30 seconds. The sound is audible and sounds like a drag being put on the engine. The AC works great.

Is this normal or could it be a relay issue?

I have a 92 240 GL. Thanks.

Brad

 

It sounds to me like you may have a low refrigerant charge. If you had some guages to get some pressures for me on the high and low side, I could help more. It could also be a compressor cycling pressure switch located on the accumulator. I've heard of people "jumping" the switch with your problem, and it fixed it.

 

The compressor will cycle some if you have the fan on low fan speed to prevent it from freezing up.

But every 20 to 30 seconds sounds like you are low on freon.