Air Conditioner not working?

Hi there,

Is the compressor turning on? is there power at the compressor wire and no clutch operation?

mark (mhpautos)

is there power at the compressor wire and no clutch operation?
I unplugged the connector to compressor and tested that and the meter showed 7 - 9 volts and clutch is not turning on. The fuse looks good to. any suggestions?

Heater problem
1996 Chevy Blazer All Wheel Drive Automatic 130000 miles

My blazer has not been able to produce hot air for quite awhile. I live up north in the -40 below region but even after running for an hour I get no hot air blowing out, only cold air.

Do you use a block heater? Does the engine reach operating temp, are the heater hoses hot?

I do use a block heater and it does get to operating temp, but I am not sure about the hoses..

If one hose is hot and the other isn't, I'd suspect a flow problem through the heater core. The parts book didn't show a heater control valve for your vehicle, but, that is a thought, where applicable.

I have a 1999 Chevy Blazer that is blowing hot air with air conditioner turned on. I have checked the coolant level but I noticed that the compressor will run for a couple of seconds and shut off. A couple of seconds later it repeats the cycle. What will cause the compressor to constantly cycle on and off?

sounds like the ac is low on freon, you can take it to have the ac recharged or to save money you can recharge it yourself with a kit that can be bought at a auto store. if you do it yourself read all the instructions carefully before you do.

It ran out of freon-have it recharge with R-134a-and you'll be cooling big time again.

i think that is all you can get is 134a these days.

That's it now a days after 94 I think! R-12 is still available at a higher price.

Just to add my 2 cents on this, if you have an R12 system, you can convert it to R134 so that you are not paying through the nose for R12. If you have an R134 system. I attached a guide on how to fill the system.

https://www.2carpros.com/articles/air-conditioner-how-to-add-freon

I have a 1999 Chevy Blazer. The air conditioner does not work. If you push the button the light flashes 3 times. If the compressor is hot-wired, cold air blows out the vents. What could be wrong with the system?

Bad control head or failed low pressure cut out switch.

is it fixed? what was it? relay? module?

get it fixed? what was it? could be a pressure (sensor) problem.

Chevy Blazer 1997 80,000 miles v6 Vortec Engine


I am trying to charge the air conditioner with R134 and I cant get it to take any of the refridgerant, Perhaps I am putting it in the wrong place? There are two spots one on the cylinder and one on a line in front of the cylinder.. The kit i bought in walmart to charge it will NOT fit on the lower one on the line in front of the cylinder, only the one ON the cylinder so I treid that one, and it will not take any of the refrigerant.. Any help with this would be appreciated.. I just have no cold air, A/C is the same as the vent about.. I

First, the charging kits that you can get from most retail stores is designed to fit the suction fitting only which is a 13 mm fitting. The fittings are designed that way to prevent you from putting the can on the discharge port, which could cause the can to explode due to overpressurization. First check that you are getting 12 volts at the connector going to the compressor and that you have a good ground.
If both are true, try disconnecting the low pressure switch and jumpering the connector's two terminals with a piece of wire or a paperclip. If the compressor will not come on then your problem is either a bad compressor or the compressors clutch coil is bad. If you don't have power then check your fuses for a blown one. Hope this helps.

Later

Gary

when i start the vehicle the a/c comes on and works fine when i rev up the engine the a/c stops working and the heater comes on. the compressor is still engaged.driving down the road the heater is on . at a stop a/c starts working again i suspected a vacuum problem so i replaced the vac hoses under the hood.the check valve is working as it should. when the engine is off i can disconnect the vac line at the vac reservoir, it seems to be holding vacuum. i removed the lower inside panel and all of the vacuum pots (that i can see) seem to be working and holding. when i am driving down the road there is no problem with air shifting say from defrost to panel etc. the gauge readings on the high side and the low side are correct

Hi Automatic climet control or manual? Would you post low/high gague readings
Thanks for donate

Ok before I be of much helps I need to know if you have automatic A/C or manual a/c. Get back to me so I help you find the problem.

the a/c is automatic i will have to reconnect the gauges to give exact pressure readings but the compressor is not disengaging at high rpms it is running full time even when i am driving down the road( i suspect that it has something to do with the door that switches from heat to cool maybe?) thanks

I suspect one of the ambient temp sensors but before we go to checking that I would like the A/C guage readings on the high and low side. Provide the outside air temp at the time you check it ok. Thanks.

ambient temp is 93f gauge pressures are 240 high side 47 low side

Ok first thing is the pressure is not correct at that temp. At 93 deg it should be low 29-37 and high 337 to 374. So I would say you are low on freon so lets get it full first and then go from there. I would say maybe one can.

ok i added about 1/2 to 3/4 can low side 37 high side 350 i checked 1 more thing . the temp of the air at the panel inside is 70 degrees at idle. when i rev the engine and hold it at 3000 rpm for a couple of minutes the air temp is 134 f . the receiver dryer is cold and dripping condensation

Ok so do you have a digital multi meter? I would like to check a couple of temp sensors.

sorry for the delay in the response. my meter seemed to be broken. i went into town and bought another one.ready for the next tests thanks

On the right side (passenger) of the radiator support there is the outside ambient temp sensor. You need to look for two wires DK Green with a white stripe and a black wire. Now with you meter simply unplug it and ohm the sensor. Now get back to me with the ohms and the air temp at the time you check it ok. We will go from there.

i located a small black box looking item mounted to the bottom of the radiator support 2 wires to it i assume that i found the right part. has a yellow and black wire running to it (maybe the wire is faded?) the reading to it is 998 with the ohm meter set at 2000 ohm setting. the outside temp is 80 degrees thanks

Ok if that was the ambient temp sensor then it way out of spec. Now I have included a pic of where it is and what it should look like just to be sure. Location

Sensor

thanks for the pic i had tested the wrong part. the sensor gave no reading on the 200 or 2k settings. on the 20k setting it gave a reading of 7.36 at 90 degrees im sure i tested the right part this time (green and black wire running to it) thanks

Ok at that temp it should read about 3900 ohms so it looks like that sensor is no good. When you tested it you just unplugged it and ohmed the sensor not the wire harness? If that is correct then it is bad. These are available at you local parts stores so there is no need to go to the dealer unless there price is better. Let me know how it goes.

sorry for the delay in getting back to you i live 30 miles out of town went in to order the part they sent the wrong one. i have the right one now installed it . same problem . i ohmed the sensor and it reads the same as the old one (within a few ohms ) i noticed that it also senses for the outside temp reading on the mirror ( when i unplug it and turn on the key the thermometer doesnt work. it is reading the correct outside temp (presently 93 degrees). thanks

Ok do you know where any of the inside temp sensors are? This is crazy according to the readings you gave that should have been it. Anyway lets move on and see what we can find.

Have you tried using in manual mode? does A/C stay cool