its getting hot here in ma. tested the ac on a recent purchase,the vents blow cool air not cold,i noticed that the climate control is lacking proper functions,if i put it on auto the blower always runs,heat works great but no a/c,the small auxillary air pump behind the glove box works for the inner ambient temp,could it be a pressure sensor,should the a/c compressor clutch operate when i turn the temp dial all the way to 65? any help would be appreciated.

You will first need to connect a set of gauges to your high and low side and inspect your system pressures. Are you familiar with the system operation? You will only get A/C function when you have selected a mode other than 'EC'. Have someone select the middle button (solid bottom arrow) and physically watch to see if the compressor clutch engages. I find the clutches are pretty quiet and hard to hear engage so a physical inspection will confirm if the compressor engages.

If it does then you still have some pressure remaining. You may have a leak that has allowed you refrigerant to leak. If it does not engage then assume that your system is likely empty. Do you know if the car is on R12 or a converted system to R134A?

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1989 300CE

It does indeed sound like a low charge, but the first troubleshooting step is to connect manifold gauges before doing anything else.

It's HOT in MA? What are you calling hot?

hi larry,i can connect gauges,but i will have to perform a visuale check to see if the clutch engages,if i had to guess i would say it still has r12 in it,i dont see the new valve fittings with the different color caps,maybe if im lucky the tech will suck out the old expensive r12 and hook me up,or i can just get the leak fixed if it has one,then convert it over myself to r134a.

oh we had a 90 degree day,lol right now its cold and rainy,i just got back from bermuda what a tease that was,