A/C help!!!

TeeWhyS13

TeeWhyS13

Spectator
Ok guys, I have an 89 240 and I'm trying to get my ac to work. For some reason the compressor clutch doesn't engage. The HVAC unit, compressor, compressor clutch, and underhood relay are good, the only thing I didn't check is the thermal switch or whatever it is, does anybody have any advice or has this happened to them? help!!!
 
interesting... where would that be?

but the blower works fine, it just doesnt blow cold...
 
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am having a similar problem. Light comes on on mine but sometimes i have to press really hard to get it on and then clutch wont engage when light is on
 
^^ yea with you

the ac light does NOT come on, just the fan light next to it, and the clutch obviously doesnt engage
 
start from the end and work your way back...make sure the compressor clutch works, then check for power to it then follow the circuit back to the relay fuse and controller......too easy...make sure the pressure switch is connected and that there is freon in teh car....the light doesnt always matter because i had 240's were the ac worked fine and the light never turned on......
 
well i have access to alldata, if anyone knows what that is, and i followed the step by step instructions for the ac control and im getting stuck about halfway through... all the physical things are fine, such as the compressor, clutch, theres freon, blower, relays, fuses, pccm, all under the dash stuff, still nothing :(
 
PlatanoDrifter said:
start from the end and work your way back...make sure the compressor clutch works, then check for power to it then follow the circuit back to the relay fuse and controller......too easy...make sure the pressure switch is connected and that there is freon in teh car....the light doesnt always matter because i had 240's were the ac worked fine and the light never turned on......
Click to expand...

how do i check the compressor i need a/c bad
 
TeeWhyS13 said:
^^ yea with you

the ac light does NOT come on, just the fan light next to it, and the clutch obviously doesnt engage
Click to expand...

hey I had the same problem the blower works but the compressor clutch wont start, this is what I did: take the control unit out and makesure all the conectors are push in really good, on my it was that can be on yours or ur control unit may be bad... good luck!
 
thanks man, but i checked both plugs and replaced the control unit with another good one and absolutely nothing changes :(
 
Ok try this. Take a thin wire and go over to the pressure sensor at the accumulator. Disconnect the plug and jump the two female connectors in the plug. If the clutch comes on then more than likely you either have a low freon level or the pressure sensor has gone bad. If that doesnt do anything than that means you arent getting power and you need to trace the wires to find out why. Now if you simply want to check if its the clutch jump over to the relay and jump it. If the clutch comes on then it could be a bad relay or once again no power. You may ask if it comes on then how could it have no power. Well the connections where the relays reverse and closes the circuits in the relay. The reversion is all done with the control unit, but if thats new then most like the problem is gonna be a cut wire, low freon, or the pressure sensor. Ive been doing A/C for years with my dad. I should of known all this on my car but im too lazy to fix it and dont really mind driving with the windows down and i wanted another perspective on what could be wrong. Neways, check those things out and hopefully you find your problem.
PS if it turn out to the pressure sensor you can leave the jump in but make sure it doesnt stay exposed. Also this is only a temporary fix so that you can have some A/C until you can change the pressure sensor over. And if your asking yes you do need to empty the system to change the sensor and if your not using a recycling system for the freon you will need to reoil the system. Hope everything works out for you
-Elliot Gonzalez
 
alright last time... the pressure sensor is the thing right next to the battery? my dad does ac and he said theres this thing on the top thats supposed to be green if its good and its not... also i checked the charge again and there was absolutely no freon, which is weird because i just charged it last week, so i put two full 13 oz bottles in... is that enough? how much freon does the system take to completely fill it from empty?
 
Ok the pressure sensor is the thing on the canister next to the battery. If you take it all out it looks like a missle with a sensor screwed into it. The way to tell how much is to look at the a/c spec sticker under the hood. It will probably say so many lbs of r12. Just convert lbs to ounces and thats how many oz of r134a youll need. And on the bubble sight its when it goes from foggy to clear. Now if you charged it last week and and it was empty again then you have a really big leak somewhere. Mine leaks from the valve and laziness has kept me from changing it. Anyways what you wanna do is vacuum out the whole system. This will take about 10-20 mins with a a/c vacuum pump. Now close the valves on the gauges and check that its holding vacuum. If I can recall it should be like 30lbs of vacuum. Now dont do anything just yet. Keep the valve closed for a good 10-20 min, make pump is off, and periodically check the gauges. If the needle begins to move more towards zero, then you have a leak. Now what you want to do is open the valve and run the pump for 5 min. Then turn it out and put in an oil charge with UV dye and recharge the system. Make sure you have a little flashlight style black light and that there isn't much light around. Go around the whole a/c system with the black light until you see a glow from the dye. Thats where your leak will be at. With a leak this big a bottle of sealant for the a/c system wont work. You have to replace whats leaking. Good luck. Hope this helps
 
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