Aircon

[dylant]

Hi, I have a '88 124 series 260E Merc and having problems it seems with electrics, for starters the aircon will switch on then off after about 5 min then not come on again, the heater switches control wrong sides ie: the left wheel heats the right and visa versa and the recirculation air switch also goes on and then switches off in about 5 min, its all very weird, I thought it might be the chip board behind the control panel where the heater wheels are attached? Any help will be appreciated!

[dylant]

Hi, I have a '88 124 series 260E Merc and having problems it seems with electrics, for starters the aircon will switch on then off after about 5 min then not come on again, the heater switches control wrong sides ie: the left wheel heats the right and visa versa and the recirculation air switch also goes on and then switches off in about 5 min, its all very weird, I thought it might be the chip board behind the control panel where the heater wheels are attached? Any help will be appreciated

Is the drive belt tight, tensioner in good shape and belt not oily? There is a sensor on the compressor that will shut down the system if the belt slips.

Good luck,

[psfred]

Belt slip or bad compressor clutch (or failing compressor) is why the AC switches off. Could be a bad KLIMA relay, too, for that matter, but you will have to get that tested to make sure. Certainly, the first thing to check is the belt condtion, then the tensioner. If you have had a water pump or alternator replaced recently, likely the tensioner is no longer working and needs to be replaced.

For the heater controls, someone has been into the console and has swapped the connections. You can remove the dash panel by pulling the knobs off, removing the 24 mm nuts (I think that's the size), then removing the two screws on the bottom edge. The wood trim then tilts up until the hooks on top come out. The heater controls are screwed to the console and the switch bar.

The recirc normally only stays on for 5 min.

Peter

[dylant]

ok that seems like it could easily be the problem, my car does have its fair share of oil leaks so It could be slipping, where can I see the clutch kicking by the compressor becuase I am not too familiar with the AC! However the whole AC was replaced once but it still switched off, if its not the belt could it be electrical?

[stevebfl]

Yes!

To get good answers one must have good information. That starts with an understanding of the system. Try reading this DIY article: ( http://www.peachparts.com/diy_stevebfl_0.htm ), use the archives to fill in holes, then figure out what is missing in your situation, then ask a bunch of questions.

[dylant]

I was reading that page of the link you gave me and thatnks it was a great help but it says the aircon will fail that test sometimes if the voltage is also low and I know there is a low voltage with the car but I never bothered to get it fixed becuase electricians take forever where I live, could this be the problem? I did clean the belt really nicely so I will try and see if that helps! But its not loose.

[dylant]

When I switch the ac on by the dash I can see the car economy taking strain but not a lot, or not as much as it used to at idle. If I switch it off the economy goes down again and then will come up again if I engage the ac again, it wasn't even doing as much as that before, but still no cold air. If I empty all the pressure from the system and then switch the ac on it builds up pressure so can I assume the compressor is working? I now think I need to get the gas refilled becuase its been a very long time since the ac worked.
Does this sound right?

[psfred]

Do not vent the AC by yourself -- you will only be wasting money.

If the AC has not worked for some time, I'd bet you are indeed low on charge, but that also means you must find and fix the leak before adding freon, or it will all leak out pretty fast again.

Typically, a system with just enough charge to operate the low pressure switch will cycle rapidly and provide very little cooling.

Peter