Air condtioning not working

Im new to this forum spend more time in the Ford Windstar one. However I have a problem and maybe someone can help. My sons S10 Blazer 4x4 4.3 litre is having a problem with the air conditioning. When you switch the air on the clutch does not engage. In fact there is not 12 voltz at the connector. I put 12 voltz to the connector and the compressor ran. I checked the relay swaped out with a new one and still no power to the compressor. I put a volt meter to the hot side of the battery and to the black wire and then the green wire connected to the compressor and both times got 12 voltz between. Why are or should both the green and black wires be grounded? When I check from either wire to the negative side of the battery it reads in millivoltz. Any ideas. Thanks.

What year?
Has it got gas in it.
What are the pressure readings?
MT

96 S10 Blazer 4x4. The problem is the compressor clutch is not engaging. I put some refrigerant in about 14ounces. It was empty. Of that 12 ounces contained the dye to look for leaks. I jumped out the ac clutch cycling switch and also checked the low pressure switch. (back of compressor.) I can however provide 12 volz to the compressor and make it run. It has not worked in a year so I know the system is contaminated and needs to be evacuated. I was checking for leaks and function before recharging correctley as I will have to remove all freon anyways. I used a charge kit from AutoZone so I only know the low side was about 60 lbs at ambient temperature of 80 degrees. Hope this helps. Thanks

Check you PM mail for a wiring diagram.
They use a 3 wire pressure switch set up.
Do not try to jump the switches.
A lot of the controls use a ground circuit for switching and turning on relays and is PCM controlled.
Reverse your test light to the positive battery to check for ground.
Check all fuses in wiring diagram.
And if the auto zone recharge kit has stop leak in it do not use or add it to system. Leak dye is good but stop leak is a no no.

MT

Just an update. I figured out the problem with the ac after looking at the wiring schematic and looking at Alldata subscription I found there was a diode in line after before the compressor and for some reason the plastic container it was in in the wire loom had melted. I eliminated the diode fixed the wire and charged the system and it works great.

Thanks for posting back how it went.
Glad you got it figured out and going.
MT

Could i got a copy of that diagram

Could i got a copy of that diagram

Welcome to AF
You got it. Check your PM e mail.
Is your same year make and model?
For more help it would be better to start a new thread.
Ans tell us what problems you are having.
What problems are you having.
MT

Welcome to AF
You got it. Check your PM e mail.
Is your same year make and model?
For more help it would be better to start a new thread.
Ans tell us what problems you are having.
What problems are you having.
MT

ty that helped and ty for the welcome
ialso have another question can you replace the preesure sawitches in a 1996 chevy s10 pickup

ty that helped and ty for the welcome
ialso have another question can you replace the preesure sawitches in a 1996 chevy s10 pickup

All pressure switches can be replaced.
If you are talking about low pressure cut out and the hgh pressue line switches.
They just screw off and on.
But the one on back of compresser the system has to be pumped down.
For more help you need to start a new thread on yours.
And tell us what it is doing or not doing
MT

All pressure switches can be replaced.
If you are talking about low pressure cut out and the hgh pressue line switches.
They just screw off and on.
But the one on back of compresser the system has to be pumped down.
For more help you need to start a new thread on yours.
And tell us what it is doing or not doing
MT
nvm i found out the compressor wasnt kicking in because the system wasnt charged i found that thanks to MT-2500s diagram because it showed me that there was a switch to check so i know the compressor wasnt broken so i charged the system and it works now

You are welcome and.
Thanks for posting back how it went.
Glad all is well and going.
MT

Just an update. I figured out the problem with the ac after looking at the wiring schematic and looking at Alldata subscription I found there was a diode in line after before the compressor and for some reason the plastic container it was in in the wire loom had melted. I eliminated the diode fixed the wire and charged the system and it works great.

You may want to replace that diode. I don't know exactly how that diode is in the circuit by your description, however if the diode is in parellel with the clutch coil it is intended to prevent the coil from generating a high voltage when the current to it is shut off (like an ignition coil - think hundreds of volts!). If it is in series with the clutch coil it is intended to prevent back feeding another circuit. Either way that diode was there for a reason and by removing it you could be causing some very nasty surprises for yourself down the road.

Sparky

Sparky1349
Thanks for the information. I had planed on replacing it. I just had a hard time finding it. No auto supply store have it or have listing for it. Even the dealer until I found a better descrition in Alldata. Rock Auto has it for like $16.00 and the dealer wants $47.00. It comes with wiring.

Just use a 1N1004 (from any electronics supply house) connected in parallel with the clutch coil. Double check the polarity before installing it. The cathode should be connected to the positive power lead for surge suppression duty.

Blue Bowtie
The leads are green and black. I believe the green is hot and the black ground. The diode supposed to go across the green and black? Or in the green line. When you say the cathode is that one of the ends on the diode? I know the diode allows current to flow in 1 direction only. So which would be the current feed side and which the load? I have nothing left to compare to except a melted plastic case. Thanks.

Still got the wiring diagram I sent you?
It shows which way the diode goes.
Look at the pointer under the _
MT

MT-2500
Thanks now which end of the diode goes toward the arrow? Is there a arrow on the diode? I dont have one so Im not sure. I will pick one up from Radio Shack like Blue Bowtie said. Thanks

All good diodes are marked which way they go.
It is shown in the wiring diagram I sent you.
MT

MT-2500
Thanks now which end of the diode goes toward the arrow? Is there a arrow on the diode? I dont have one so Im not sure. I will pick one up from Radio Shack like Blue Bowtie said. Thanks


The symbol for a diode is -->|--- The arrow is the direction that current flows, in this picture the anode (+) side is on the left and the cathode (-) side is on the right. If you get a 1N4004 (1 amp 1000V diode) from radio shack it will propably be black with a white band around one end. The white band is the cathode. The cathode will be 12V when the compressor is running and no current will flow. If your not sure open the package at radio shack and have them use an diode tester/Ohm meter set to diode test to show you the current flow. Remember you don't want to put it in so it flows current during normal operation or you'll have another diode just like the first one that burned up.

Good Luck
Sparky

Sparky1349
Thanks for the explanation. Ill pick up a diode tommorrow.