1996 A/C Clutch Engaging Issue

[Fahnessin]

Hello,
I am having an issue with my a/c clutch not engaging on my 1996 Explorer Eddie Bauer with around 180,000 miles. The a/c clutch will only engage when I jump the pins in the relay within the power distribution box. I am not exactly sure about these numbers but I believe they are the 86 pin and the 87 pin. If you are looking as if in the driver's seat it is the pin on the right side connected to the pin in the middle.
I have recently checked fuses and the relay works when switched with alternatives.
I have replaced the entire compressor. I have replaced the accumulator. I have replaced the orifice tube. I replaced the R134a while system was on when jumped.

Everything works when jumping those pins and the a/c is blowing cold. When I replace the jump with the relay the compressor disengages. Please help me find a solution; the idea of another summer in Georgia without a/c is keeping me up at night. Thank you for your time.

 

[drakon543]

could be one of the high or low pressure switches. if the switch is bad it will make the system think there is a problem and wont allow it to run. also when you replaced the compressor did you refill it yourself or did you have a shop do it. im not overly familiar with a/c systems especially on your ford but if the system isn't charged correctly it might not work. the systems are purged and then a vacuum is applied before it starts actually charging. far as im aware you can't just recharge them with those diy cans when the system has been opened.

 

[Fahnessin]

I purged the system with the help of a mechanic friend who is semi-familiar with a/c systems. We recharged the system with the vacuum. Everything works as designed when jumping the pins but not with the relay so I am assuming the high and low pressure switches are working. Perhaps I am wrong to assume that. How can I test to ensure both switches are in working order? Thank you for your time.

 

[8TZX]

Om a 99 5.0, The high and low pressure switch circuits are in series with the AC Relay coil. If your jumper is across the COM and NO contacts of the relay then you are bypassing both high and low pressure switches and the clutch will engage without any safety circuits. You might try and test both the low and high pressure switches one at a time. Disconnect the low pressure switch and install a jumper between the two pins. See if the clutch engages. If not, reconnect the low side and disconnect the high side and install the jumper. You said you charged the system. Did you note what the low and high pressure readings? FYI, the low pressure switch is normally open at or below 24.5 psi, closed at or above 43.5 psi. The high side pressure switch is normally open at or above 430 psi and and closed at or below 250 psi. If you have to replace either switch, you do not have to evacuate the system as they have a schraeder valve.

 

[ThreeJs]

When my A/C stopped working it was the EATC unit. Right around 180K also.

1996 EB Explorer EATC

I lost power to my AC compressor and after doing tests I'm positive it is the EATC unit. My research leads me to believe Explorers have different EATC units. One for 95-97 Explorers and one for the later 98-up and they are not interchangeable? Can anyone confirm this? Used ones online are...

www.explorerforum.com

If both high/low pressure switches check OK try jumping 12V to compressor.

Quote Aug. 30, 2018:
"I have a 86 EB Explorer.
My AC stopped working a few weeks ago. I'm in Vegas so it's been HOT!
Took to work and had it checked. System was full. No power to compressor or at low pressure switch..Tech said somewhere in the dash. I needed to leave work early that day so I asked if we could just get it to work somehow.
We hotwired the compressor to battery positive terminal and AC works. I've since hooked the AC power wire to a keyed ignition source so I didn't have to keep disconnecting the power wire everytime I parked.

I think it may be the EATC module but will look into it after the weather cools down. "

 

[Fahnessin]

I thought that was the case...I was pretty sure that the jump was bypassing the switches but I was not sure thank you for the clarification. I have jumped the low pressure switch with the relay in and the clutch did not engage. I will try the high pressure switch tomorrow and post my findings.
Also I did not check the readings on either switch; I will also do this tomorrow.

I have been reading some posts about the EATC unit causing issues as well. I will try your suggestion and repost.
Thank you for your time.

 

[8TZX]

I thought that was the case...I was pretty sure that the jump was bypassing the switches but I was not sure thank you for the clarification. I have jumped the low pressure switch with the relay in and the clutch did not engage. I will try the high pressure switch tomorrow and post my findings.
Also I did not check the readings on either switch; I will also do this tomorrow.

I have been reading some posts about the EATC unit causing issues as well. I will try your suggestion and repost.
Thank you for your time.

See attached wiring diagram from the 99 factory wiring diagram manual.
Good luck

 

[ThreeJs]

Just a FYI also........The early 2nd gens used a different EATC than later years.
Explorers have different EATC units. One for 95-97 Explorers and one for the later 98-up and they are not interchangeable

1996 EB Explorer EATC

I lost power to my AC compressor and after doing tests I'm positive it is the EATC unit. My research leads me to believe Explorers have different EATC units. One for 95-97 Explorers and one for the later 98-up and they are not interchangeable? Can anyone confirm this? Used ones online are...

www.explorerforum.com

 

[masospaghetti]

I've had issues with a bad shraeder valve in the accumulator port for the low pressure switch. It caused the same issue as you described. I removed the bad valve from the port and everything worked as designed.

Of course, if you do this, you'll lose all of your refrigerant if you ever remove the low pressure switch.

Check the low pressure switch to see if it has continuity or not.

 

[Summajet]

Have you tried a jumper wire at the cycling switch located near orifice tube?