A/c Woes - Page 2 - PeachParts Mercedes-Benz Forum

Arthur Dalton · #16 07-02-2007, 08:21 PM

Yeah....I found the best place is to just tap across the drier switch with a cabin sw ...that way you have LOW fan [ which does not drain so much power off alt , yet enough to have airflow]..what is nice about that set-up is you just leave it connected and when the sw is OFF, the system is back to stock and works according to normal spec., but you have the option of Over-riding the system b/c your cabin sw is in parellel once you turn it ON..best of both worlds,

Another advantage to cabin sw over a resistor bridging at the ACC sensor [ blu 2 wire temp sensor modification] , is you do not have to worry about the temp differential between cut-in/cut-out.... with a cabin sw, it is at your discretion and definate ON/OFF...

E150GT · #17 07-09-2007, 08:10 PM

Well today we had our first sunny day at im guessing 80 degrees outside. My A/c really dissapointed me this afternoon. I know it was stop and go traffic but temps in the 60's on an 8o degree day? What wil happen when it reaches 100 degrees? So i posted earlier that the compressor would not kick on after a hard rain, and it turned out I could pull either connector off the coolant temp sensor and the compressor would work and all is well. now after sweating in the a/c i pulled over to make sure my aux fan was working and it seemed to be on low. I plugged in all connections to the sensor and the compressor stayed on. i forgot to mention in stop and go traffic the temps were creeping to 100c and i shut off the a/c. when i pulled over i plugged in the connections to the temp sensor and it seemed even though i was idling still in the heat the temps went down to just above 80c and the vent temps went down to 50c. Would the temp sensor fail intermitently or would this indicate another problem unseen? Also am I expecting too much from this vehicles a/c? If i keep the car at 40mph or above I can get 45f at the vents no better.

gmercoleza · #18 07-09-2007, 08:24 PM

Has the system been converted to R134a? If so, that type of performance is about as good as you are going to get, since the system was originally designed for R12. In my converted 380, I can only get down to 48 degrees from the vent moving at 40mph when it's 86 degrees out. It gets even warmer when it's 100 degrees out.

E150GT · #19 07-09-2007, 08:29 PM

it is still r-12

E150GT · #20 07-09-2007, 08:39 PM

I forgot to ask why sometime is see bubbles in the sightglass and now i hardly see any?

gmercoleza · #21 07-09-2007, 08:56 PM

With R12 you should be pulling 38 degrees at the vent easily. Something is definitely wrong.

E150GT · #22 07-09-2007, 09:50 PM

yes sir. something is rotten in Denmark

david s poole · #23 07-09-2007, 10:33 PM

why don't you make sure that the fresh air door is closed.even r12 won't cool texas and put it into the car below 60deg.check the grills right in front of the windshield with paper and see if sucking air in there.get some of the black tar like stuff for wrapping sweating a/c pipes and use it to close off those grills.

saumil · #24 07-09-2007, 11:08 PM

Stop and go traffic is a different condition than idling. In stop and go traffic, you are behind another car which blocks fresh air and possibly raises the temp at the front of the aux fan. So you can expect better cooling efficiency at idle than in stop and go traffic. Also make sure your aux fan is turning in the correct direction. If you us a small piece of newspaper and bring it close to the aux fan in the front, the paper should get sucked in as opposed to being blown away. The air must flow from outside to inside the engine compartment.

How many pins are on your temp sensor ? Three ? On my car, I have a single pin connector for Klima relay and a seperate two pin connector for the aux fan.

You can try shorting the two pins that belong to the aux fan relay on the same temp sensor from which the Klima relay gets its input (the one pin you disconnected). The aux fan should run right from the very beginning, when you start the car. This should keep your car cool all the time.

gmercoleza · #25 07-09-2007, 11:12 PM

when set to max cold temp (wheel clicked at the end of the "blue" section), the recirc door should close. Pull the glove box lining and you will see it staring right back at you and will be able to tell if it is sealing properly.