Question about 1999 Jeep Grand Cherokee

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My air conditioning unit is fully serviced but only blows warm air. The low pressure side hose does not get cold and there isn't any condensation dripping from the system. I have the same problem. The compressor clutch engages and cycles because of excessive pressure in the system. I just went through the nightmare of replacing the radiator and I am wondering if there may be a connection. Maybe I bumped a connector or something. If the relay is bad will the A/C compressor clutch still kick in?

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  • sandyrod Sep 08, 2008

    Yes the compressor is engaging. Thanks.

  • yadayada
    yadayada May 11, 2010

    If the compressor engages the relay works, does it turn off and on every 6-10 seconds? Are you sure the system is not overharged? Do a live chat and we might figure this out.

  • yadayada
    yadayada May 11, 2010

    Is the compressor engaging?

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Is the system full? Jeeps have a long history of bad evaporators. Even if the system was serviced, you could have lost the freon overnight. Compressor cycling can be because of not enough freon also.

Posted on Nov 07, 2008

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2007 ford KA blowing hot air


see this causes and fix it. God bless you
Compressor Checks
checkmark.gif Start with the compressor. Does it engage when you turn on the A/C?
If so, the compressor is working and the A/C system probably contains enough refrigerant to make cold air, so the problem is inside the HVAC unit. Replace the motor that controls the blend air door (this is a difficult job and best left to a professional since it involves tearing apart the HVAC unit -- about an 8 to 10 hour job!).
If the compressor does not engage when you turn on the A/C, see if it will run by jumping the compressor clutch wire directly to the battery (use a fused jumper wire). If the compressor works when you jump it, and the A/C blows cold air, the system contains refrigerant and the fault is likely a bad A/C compressor clutch relay or a bad clutch cycling switch or pressure switch.
If the compressor does not engage when you jump it, the problem is a bad compressor clutch.
If the clutch engages but the compressor does not turn (the belt will start to slip and squeal), the compressor is locked up and you need a new compressor.
If the compressor clutch engages and turns the compressor, but the A/C still does not blow cold air, the system is probably low on refrigerant and needs to be recharged.
Refrigerant Checks
checkmark.gif Connect an A/C pressure gauge to the HIGH SIDE service port (located in the high pressure hose that runs between the compressor and the condenser in the front of the engine compartment). The gauge will tell you if there is any pressure in the system. Simply depressing the service fitting valve with a small screwdriver to see if any refrigerant squirts out is NOT an accurate check because it tell you how much pressure is in the system. It may still have some pressure but not enough to trip the low pressure safety switch so the compressor will engage.
If your A/C system is low or out of refrigerant, check for leaks, then have the A/C system vacuum purged to remove air. After the air is out, it can be recharged with the specified amount of refrigerant. It is important to get any air out as this will reduce cooling efficiency and may make the compressor noisy.
A/C System Functional Checks
checkmark.gif If the refrigeration circuit seems to be working (refrigerant in the system, compressor running and building pressure), but there is still no cooling, the problem might be an obstruction in the orifice tube (located in the high pressure hose between the condenser in the front of the radiator, and the evaporator located in the passenger compartment). A blockage here will prevent the refrigerant from entering the evaporator or recirculating through the refrigeration circuit.
If the orifice tube is plugged, the high side pressure reading will be lower than normal, and the low side reading will also be lower than normal because no refrigerant is circulating through the system.
checkmark.gif If the refrigeration circuit seems to be functioning normally (compressor running, frost or condensation on the high pressure line from the condenser to the evaporator), but no cool air is blowing out of the ducts inside the car (and the blower is working), the fault is likely a BLEND AIR door that is stuck in the HEAT position, or possibly a badly clogged cabin air filter that is restricting airflow. Another possibility would be a fault in the automatic climate control system such as a ad interior temperature sensor or control module.

Sep 28, 2012 | 2007 Ford Ka 1.3

1 Answer

My air condition is not blowing cold air


best diagnostic method is dual head gauges. balanced pressure between low and high side in the off position is aroung 90 lbs. running low pressure is 20-40 lbs and high pressure 160-200, is the compressior not coming on? does it stay on, or click on and off. either might mean the freon level is low. try unplugging the low pressure switch on the low side supply line and shorting the pigtail wires together with a paper clip. does the compressor stay on now? if so and the air is warm or cool, freon is low. if the air is cold that switch is bad. if compressor still won't come on the list of possibilities grows longer: compressor, comp fan clutch, AC relay, restriction at several places... repair shop time...

Sep 04, 2010 | 1991 Buick Riviera

3 Answers

98 buick century AC blows cold air on passenger side and hot air on drivers side..when we recharged the unit, it worked cold air for a few days and now blowing hot air again.


Hi. There seems to be a blockage within the system. I will list all parts to be checked by your mechanical. I would also have the blend door linkages or servos inspected for fail points along with the listed areas of concern, below:

Loose or broken drive belt
Inoperative compressor or slipping compressor clutch
Defective expansion valve
Clogged expansion valve, receiver-drier or liquid refrigerant line
Blown fuse
Leaking component: any of the parts listed above or one of the A/C lines, hoses or seals.

Instruct your mechanic to check all the above, along with the dash blend door linkages for faults.

Aug 11, 2010 | 1998 Buick Century

2 Answers

How to recharge recharge airconditioner


Hi, determine if your car uses R134 or R12 refrigerant. You will notice screw type connectors on the both the High Pressure Side and Low Pressure Side lines in models using R12 refrigerant. R134 compatible models have quick connect valves on both sides. Models made before 1995 may use the old R12 refrigerant. If this is the case, you must have your Chrysler's air conditioning system retrofitted to use R134 refrigerant. Mixing R12 and R134 refrigerants is dangerous and may cause damage to your vehicle. Check your air conditioning system pressure using an automotive air conditioning pressure gauge. Keep in mind that in order to get an accurate reading, the air conditioner has be turned on the coldest setting with maximum blowing power. Remove the Low Pressure Side port valve cap and set it aside. The location of the port varies, but it is usually in front of the engine block. Attach the refill hose to the port on the Low Pressure Side of the air conditioning system. The Low Pressure Side port is smaller the High Pressure Side port. Because the ports are different sizes, the refill kit hose should fit only on the Low Pressure Side port. Additionally, the High Pressure Side port will usually have a red cap or be marked with an H or the word High Allow the air conditioner to **** the refrigerant out of the can by slowly turning the valve on the refill kit hose. Pay attention to the way you hold the can. Most kits will have you hold the can upright when you recharge the air conditioning system. It may take as long as 10 minutes to empty a single can. Turn the valve to the off position and remove the refill hose from the port. Recap the port before closing the hood. Let the air conditioner stay on for at least 30 minutes. This allows the refrigerant to move throughout the entire system.
Take care

Aug 03, 2010 | 2006 Chrysler Town & Country

2 Answers

A/C NO LONGER BLOWS COLD


sounds like the a/c is not fully charged, have the system serviced by pulling the freon out and pull a vaccum on the system and recharging with proper amount of freon. this should fix the problem. if when fully charged and this happens either the high pressure switch or low pressure switch could be bad.

Aug 24, 2009 | 2000 Acura TL

1 Answer

2000 chevy tahoe air conditioning blowing warm air


probably a leak.

what are your high and low side pressures?

Aug 01, 2009 | 1996 Chevrolet Tahoe

1 Answer

The a/c on my 2006 honda pilot is not owrking and appears to have a low refrigerant charge. I want to recharge it and find the leak with die. what is the amount of 134a to be fully charged


Adding freon or topping off a cars A/C system is the most common task performed to restore performance and get cold air blowing again. However, adding refrigerant isn’t always the solution for car air conditioning problems. There can be many other things wrong besides a system being low on refrigerant. To diagnose problems, an A/C manifold gauge set is needed to read high and low side pressure readings. Avoid adding refrigerant with a simple charging kit like the ones sold at parts stores. Don’t add any stop leak, this can cause problems in the compressor, expansion valve or condenser.
Keep in mind that using an A/C gauge set and seeing BOTH high and low side readings can help in diagnosing the problem when you know what to look for. First, on a 134A system the high and low side service ports are different sizes. AC gauge sets have color coded hoses, the blue color coded hose has a connection that fits on the low side service port and the red hose has a connection that will only fit onto the high side. The yellow hose won’t hook up to anything if just checking the readings; it can be used to connect to a vacuum pump or attached to a refrigerant can or tank.

*Make sure the condenser fan comes on when the readings are being checked.

Normal readings on high and low side with AC OFF (static pressure) - Depends on outside temperature, but normally is between 80-105 PSI
Normal low side reading with AC on high speed and MAX & engine at 800-1000 RPM’s - Ranges from 25-35 PSI - Note that on many Chrysler products a normal reading on the low side may be 15-25 PSI
Normal high side reading ranges from 200-350 PSI

Don’t assume that if adding little Freon is good that adding a lot is better!  Overcharging just a little can decrease the performance of the system and possibly damage the compressor.

With the AC on the coldest setting, use a thermometer in a middle vent. Normal vent temperature readings will vary depending on the (ambient) outside temp. The vent temperature should range from around 42-55 degrees in my experience. If normal gauge readings are obtained and the vent air is cold - STOP don’t overcharge the system. The only proper way to remove refrigerant is with a AC recovery machine so if this is being done at home I can’t emphasize enough not to over charge the system. And actually the best way to insure the proper charge is in a system, is to use an AC machine to recover the R143a and then evacuate and recharge the system with the correct amount. Most cars have the specified amount on a decal under the hood. 

Hope this helps. Keep me posted, be glad to help get you cooled again. 

Jul 01, 2009 | 2004 Honda Pilot

1 Answer

Would like to recharge my air conditioning on my 2001 nissian maxima that has 117,000 on it blows hot air when air conditioning is turned on.


You will need R134a, and a filler hose. Charge the system on the low pressure side, it should have a blue cap on the charge point.
Your filler hose will only fit the low pressure side, just in case the cap has been removed.

May 23, 2009 | 2001 Nissan Maxima

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