I am trying to troubleshoot my car's AC (it's hot!). It's a 2005 E320 wagon with the two-zone system. The controller seems to be OK-but the compressor never comes on. The charge pressures seem normal (static low-pressure measured 100psi on a 98 degree day). The diagnostic computer says the pressure is 10 bar-way higher than it actually is. Can anybody give me the static readings I should get off the refrigerant temp/pressure sensor (two sensors in one housing)? Also, where is the line that activates the valve in the compressor? None of the diagrams I got from Star Info or WIS spell this out. Lots of block diagrams, but I want to know what wire to probe!

The electrical line to the compressor is connected next to the one of the pressure lines at the top of the compressor. I *think* it's not a simple 12V on or off, it may be a pulsed DC signal to vary the swash plate. As you noted, the compressor is engaged all the time, no traditional clutch.

I borrowed an SDS computer which gives all the A/C parameters, it was essential to do the diagnostics on the system.

Refill is 2lbs, 2 oz. I was also seeing some high pressure in the system, more than I was accustomed to, might have been due to the 95 degrees and high humidity...
Static was around 120 on the low side, 140 on the high side at rest.


Jim

Jim

__________________
14 E250 BlueTEC black. 45k miles
95 E320 Cabriolet Emerald green 66k miles
94 E320 Cabriolet Emerald green 152k miles
85 300TD 4 spd man, euro bumpers and lights, 15" Pentas dark blue 274k miles

Thanks for the prompt and meaningful reply, Jim. Was your compressor coming on? what was your fix?

W211 CDI refrigerant charge amount

Jim

__________________
14 E250 BlueTEC black. 45k miles
95 E320 Cabriolet Emerald green 66k miles
94 E320 Cabriolet Emerald green 152k miles
85 300TD 4 spd man, euro bumpers and lights, 15" Pentas dark blue 274k miles