A/C dead!??

[91explorer1009]

I have had my 91 ex's ac retrofitted last year and leak tested and the whole 9 yards. Everything worked for the year great, blew cold no problems. The truck sat for 2 weeks and when I went to turn the ac on for the first time in a while all I got was hot air. I didnt hear any compressor turn on, or clicking which is what I usually hear from the engine. I am wondering if there is something that could be checked like a wire or something, I checked all the fuses and replaced the ac coil one. Nothing but hot air, it is 90++ here and I paid 400 dollars less than a year ago, please need help!

 

[ExplorerDMB]

Is the compressor spinning, clutch engaging and disengaging? You could have a slow leak. Throw some dye in the lines and let that circulate. Good luck.

-Drew

 

[91explorer1009]

no its not spinning, not engaging, any thoughts?? It showed no signs of breakage just doesnt turn on now...

 

[91EX4x4]

I replaced the ac coil fuse because it was bad, and then when i was installing my electric fan i found there was no power going to the ac compressor. So what you might want to do is see if you have any power going to the ac compressor. The possitive lead to the ac compressor(or at least my 91 eb) is the yellow and black wire. There is a brown plug(with 4 wires) in the passenger side engine bay, 2 wires split off and go to the accumulator, and 2 wires go to the ac compressor.I tested mine at both ends(at the brown plug and at the ac compressor plug)

 

[91explorer1009]

guys is there anything else small I could do like a wire or fuse or some kind of connection, has this happened to anyone before? I turn it on and the orange light comes on and blows hot air, doesnt even turn on and sometimes after a while of driving the orange light turns off on its own...please help I know someone else probably experienced this before

 

[budwich]

Not really an AC guy, but there is a pressure switch near the dryer (accumulator??). This switch usually operates if you have little or no freon. Unplug and short the connector (of course, check the connections to see what's on them before you do this), this should operator your clutch on your compressor. If it does, then it could be the switch especially if you can then feel cool air coming out of your system. If there is no cool air, then it is likely that your freon has found its way out thru a leak somewhere and you need to go thru the normal AC checks to find where. Hope it helps.

 

[91explorer1009]

where is this accumulator switch near what does it look like do you have a picture?

 

[Crizz]

The compressor-clutch does not engaged if a/c runs dry. Which coolant do you use ? I guess it´s a R12, if you have had used any other kinda coolant you can throw your compressor now. Check the label placed close to the firewall for coolant type and don´t use any other coolant execpt official replacements like 401. Don´t use R134a if the a/c is not specified for it, it will kill the compressor soon.

Hope your a/c is only leaky, it´s mostly the prob of the first gen´s, the sealers become hard and get leaky.

Check if ther´s pressure on the a/c lines, there is one or two valves like those on a bikes tire where the a/c can be filled and checked.

 

[91explorer1009]

crizz, I have R-134a the system was retrofitted two years ago. How can I throw the compressor now as you said?? So if the system went dry the compressor will not cycle? How can I test this, I was told there was no leaks at the time and it ran fine for two years, is it possible to run completely dry in 2 weeks? Could it be a bad connection or something? Also is it hard to re-charge my a/c with the kits they sell? Does anyone reccomend and certain kits to get or to stay away from? also what about a pressure switch, where is it located and how hard is it to replace?

 

[Crizz]

To check if the a/c lines are under pressure just push the fill-in-valve. If you hear a blow it´s okay, if not the a/c is dry.

Compressorclutch could be damaged, bu it´s really rare that they dont work. Check the connector on the compressor, maybe a contactproblem. Would explain why it fails after 2 weeks off duty.

I´m surprised you have an R134a-A/C, in GE the R134a was mostly built in in the 94 / 95 and following, the 93 Euro-XP has a R12 like my ´90 US-XLT ( I learn day by day ... )

 

[Jason94sport]

He converted it to 134a 2 years ago.

 

[Crizz]

thx Jason - guess I need to improve my english, soon must have read over this, sorry...

 

[91explorer1009]

i bought a coolant recharge kit with a gauge, but it says to have the air on high and the compressor cycling, which I do not hear, it is the top one connected to the belt correct? If it is not cycling on and off will I be able to test the ac refrigerant?? Please, I dont want to replace the compressor if it could be a bad switch or something, anyone think so?

 

[Longjohn119]

Put your gauge on it and read the pressure, if it is low then the clutch will not be engaged ... so if it does read low, then add some refrigerant to get the pressure up to get it to turn on ....

The power path to the compressor clutch goes through the AC relay, then through the low pressure switch, then to the compressor clutch ... you can also pull the connector to the low pressure swith and temporarily jump it, turn on the AC and if the clutch engages you are most likely low on freon but could also have a bad low pressure switch ...

Best way to tell is get a gauge on it and take a pressure reading ...

If you don't understand a word I'm saying you are best off taking it to a professional

 

[hermitrl]

Just add a can to the low side while the truck is running----when the pressure gets in there the compressor should start kicking on and off.

 

[Longjohn119]

What if there is already a full charge in the system and he actually has a bad relay or pressure switch? Then he'll have a bad relay AND an overcharged system

Take a pressure reading, you have a gauge now, if you don't understand what the pressure you read means post it here and someone will help

1st step is to take a pressure reading even though the compressor won't start, then we can break it down into a charge problem (Actually a leak problem) or an electrical problem

 

[91explorer1009]

First off thanks for all the responses. Secondly I hooked up the gauge without the compressor cycling and it read low, so I added some r-134a and it began cycling, so it was a low charge. Now the compressor is cycling on and off every 5 seconds. The gauge is reading from the low green (25 psi)then raising up to about little below mid yellow (54 psi) then the compressor turns on and it lowers back to 25 every 5 seconds repeatedly. So everything seems about normal with the a/c except one problem. Now it is not blowing cold, I figured maybe it took a little bit of driving to get the system charged or whatever, but after some driving at around 50 mph, it is still blowing luke warm air on max a/c. Now I don't know where to go from here since the system is charged and the compressor is again cycling...

 

[Crizz]

When comp. is cycling, check if the a/c-lines become cold ( passenger side, close to the firewall ). If they become cold it´s a problem with the vacuumcontrol. There´s a valve underneath the glovecase, right side, under the cover. I´m not sure if it´s for hot/cold, maybe anyone can say more about that.

If the lines do not become cold, the condenser could be bad. Usually after a view min´s running the a/c at max., a little water should drop out from the condenser, you should see it on the ground.

 

[Glacier991]

a 5 second cycle is still indicative of a low charge. Try adding a little more refrigerant until your cycle times get longer - maybe 20 - 30 seconds or so and check your vent temps.

 

[91explorer1009]

should I try adding a little more even thought the pressure is going into the yellow on the pressure gauge, it says alert, right after the blue filled??