Ford Explorer Compressor Staying On | Ford Explorer Forums - Serious Explorations

  • Register Today It's free!

Ford Explorer Compressor Staying On


New Member
September 28, 2010
Reaction score
City, State
Year, Model & Trim Level
'93 XLT 4x4
My fiancee's 1993 Ford Explorer (1st generation) lost all of its cooling capacity one day when she went to turn it on. Went to check the pressures with my manifold gauge, sure enough, very little in the system. I found the leak easily enough when the high side pressure cap popped in my hand and I found that the Schraeder valve had been leaking profusely. Replaced the Schraeder valve and connect my HVAC pump. I let it run for about 30-45 minutes to make sure all of the moisture had been extracted (to my surprise, the car had been retrofitted already and I question how well the job was done the first time).

Cracked open a can of ester oil and filled the charge hose. Added about 26 oz. of R134a, with the engine running. Originally, the compressor would not turn on, as expected because of the low charge. As I charged the system though, it started to cut on, I would say at about 8 oz or so and it cycled rapidly. Again, as I would have expected. Then, as I continued to charge the system and finally got the high side pressure up to about 250 psi and the low side at 50 psi, the compressor stopped cycling and just stayed on.

AC is working great, better than ever, but what concerns me is that when you turn the AC on, the compressor clutch engages but the compressor stays on. It never cycles. When you turn the AC off, the compressor clutch disengages just fine and when you turn the AC back on, the clutch engages just fine again. So the only problem I have is that the AC compressor just stays on too long.

Looking at the gauges, it looks like the system just stays at a steady state- low pressure reading about 50-60 psi and the high pressure reading 250 psi. It never drops or cycles because the compressor is always on. Any ideas? I'm thinking it could potentially be the AC thermostat switch, but what I find unusual is that it would fail when the system was previously cycling just two seconds before.

Thanks in advance,