So I had the A/C system practically redone. New compressor, dryer etc.. Now I'm noticing the clutch on the A/C compressor kicking on and off. Sometimes it doesn't stay on long enough to cool the cabin. The noise it's making almost sounds like a nail gun firing off nails.
I brought it back to the A/C guy and he went over the whole system and determined it was not becuase of his work or related to his work. What he found was when you apply pressure to the A/C relay it triggers the kicking on and off. He thinks I have a short somewhere.
I played around with it on my own by taking off the cover to the relay. There is something going on here but it doesn't happen all the time so I can't just rule out the relay. Any ideas???
This is an 85 300D. If someone had this happen to their car I would be interested in knowing what is causing this and if indeed it can be fixed with a new relay or what?
The noise has a lot to do with the oil in the system, but since it's all new maybe it will go when the AC has worked for a longer period of time.
There are some things you can check with a multimeter.
There's a line coming from the compessor to the pressure switch on the dryer(blue/white) the other is ground. From the pressure switch is a (blue/white) line going to the climate relay (pin 1). Check for some resistance in those two lines, if not the pressure switch can be faulty or the reay got stuck somehow (it's possible to open up these things and check it)
ps. I don't like people who start claiming they did't do it
I'm going to look into this "pin" this weekend and see what I find.
The nail gun reference is the sound I've heard around an air compressed tool that fires nails. The clutch on the compressor didn't make this noise for about a month after I had the new system. Everything worked fine and I had cold air coming out the side vents.
I don't care much for the mechanic who serviced the air. He didn't even fix the center vacuum element. He tried but he called me to say he would go over his quote by a couple hundred dollars - labor. I told him to forget it and that I would do it on my own. (I found out how to do it through the glovebox.)
I've already removed the glovebox I can see the foam hose melted away (the foam hose that connects the in dash temperature sensor hose with the hose that goes to the lower side of the passenger door) and so this weekend I will be replacing that as well as trying to replace the center vacuum element.
Any idea what material is the best to use to replace the hose? I've heard pipe insulation and someone else said they just used a plastic hose that fits over the other two. It seems MB chose a foam hose for a reason.
I finally figured out what was wrong. The A/C relay needed to be replaced. Expensive part but once I plugged it in it only makes the noise when it turns the A/C compressor on and off at limited intervals (when needed).
Warndreicke in the trunk.
Linear Mode
