Air conditioning clutch will not stay engaged

-Are you talking about air conditioning compressor?
-If so. Here there are few thing cause not to engage.
1. Freon is too low. (Or none at all)
2. Compressor itself is bad.


Mai Lor

The pressure means nothing as far as the state of charge. You need to have the system completely evacuated and recharged with the specific charge weight for that vehicle. Only then can the pressures or anything else mean anything.

Air Conditioning problem
2004 Chevrolet Impala


Ac is not blowing out cold air. You have to put gages on the system and it shows its has freon.Checked all fuses and relays. The two fans in engingine compartment do not come on when the ac is turned on but does when the engine gets hot. The compressor engages when turned on also.
If the magnetic clutch engages the compressor and still no cold air could be still low in freon or the HVAC unit.

Blower motor not working all the time...if I bang the dash near the glove box, it comes on then works great. Is this the switch assembly, the resistor problem, or should I be replacing the blower motor?

it's either low (in spite of your readings) or your a/c clutch is not working correctly or you have too big an air gap in the clutch.
First, just disconnect the 2 pin connector from the a/c pressure cycling swithc and jumper the 2 pins with a wire to force the clutch to stay engaged. See if it blows cold then, and stays engaged. You can run this way for about 15 minutes before you have to pull the plug.
report reulsts.

please don't forget to rate.

it sounds like you are low on r-134 an easy way to to check in to put a paperclip in the a/c high pressure pigtail (conecter on the wire side) and try using your a/c. if it works all you need to do is have your a/c serviced. mind you if it is low you also have a leak that needs to be fixed as well.

Try unhooking one of the battery cables and leave it off for at least 20 minutes. When you hook it back up the computers should re-boot. That has solved problems for me with heater, interior lites, power windows, AC, day time running lites, power mirrors, fast idle, rough or slow shifting, CD player, and wipers on GM autos and S-10 PU and Dodge trucks. None of the switches are connected to the device they control anymore. The switch tells the computer to open the window and the computer sends a signal to the window motor. When the computer gets confused strange things will happen or not happen. Things like one headlight stays off etc. I actually had to do it twice on my Bonneville because the first time the AC blower would only work in low and medium. After the second re-boot, everything was fine. Of course you may have to re-set your radio stations.

high pressure switch is kicking out on overload, replace it or you might have too much freon

I can tell you general principles about A/C but have not worked on a Hyundai. If the A/C lines under the hood and directly from the black cylinder tank are frosted or sweating, you have Freon circulating.

There are 2 cutoff switches in all systems. A low pressure and high pressure cutoff. The ideal amount of Freon is in the middle of these 2 pressure points.
In this way the compressor clutch will stay engaged the longest and keep the Freon circulating the longest. This is the way you get COLD air.

There are ways to measure the pressure and to find leaks. You can sometimes loan tools from Autozone or Oreillys for a deposit. Before blaming another electrical problem for the lack of COLD air you should test the pressure of the Freon left in the system. If you are within 90 days or 3000 miles, most minimum warranties cover the parts. With factory warranty it should go farther.

In answer to your electrical concern, yes there is another system controlling the A/C. The ductwork has either vacuum operated or electrically operated doors (flaps) under the dash. These "doors" blend the airflow by mixing cold and hot air to give you the temperature you want. If you want all COLD you keep the heater door shut and so on.

So you look at these areas separately first. Under the hood is the Freon pressure good? Pipes sweating? Compressor clutch on steady? And if everything under the hood is good, then you look inside the car at the ductwork.

I hope this helps you.

check if a/c has a full charge =if ok check pressure switches you might have a defective one.

did you check system pressure? approx. 30lbs.if ok then either comp. clutch coil is weak, too much clutch gap, pressure switch weak, relay is cutting out too early. also check high side pressure to confirm plugged in line filter.