I have a 2006 TC A|C suction pressure too low keeps cycling off when driving over 40, air duct temp stays around 60 no codes in heater control. Replaced compressor, dryer, orifice tube. Also flushed system, replaced high pressure hoses. Works great when in city. Air temp at 40 suction side about 25-26 at idle. Can make cycle by raising RPM around 2000 RPM?
With what you are telling me about the pressure on the low side I'm sort of questioning how much R-134a was used because it might be possible you may have to add a little more.
Using pressure gauges and a scanner you can properly diagnosis pressure problems by comparing the gage readings to the electronic readings on the scanner. This can help diagnosis a bad switch.
I feel you may need to add a few more ounces of R-134a to bring up the low pressure to about 30 psi at idle at a temp of about 80 degrees. Your high side pressure should stay in the range of about 250 psi to 300 psi depending on the outside temperature. The hotter it is outside the higher the pressures will be.
I listed the specs for the pressure, R-134a and oil below. If you are still having a problem after adding more refrigerant get back to me and we can go on from there with diagnosing the problem further.
A/C Cycling Switch:
Open pressure 159 kPa (23 psi)
Close pressure 290 kPa (42 psi)
Refrigerant Lubricant and Capacity:
PAG Refrigerant Compressor Oil (R-134a Systems) YN-12-D WSH-M1C231-B
Capacity 207 ml (7 oz)
Refrigerant and Capacity:
R-134a Refrigerant YN-19 WSH-M17B19-A
Capacity 0.651 kg (23 oz)
(a) Manifold gauge set pressures may vary slightly depending on the distance between the service gauge port valve and the A/C pressure relief valve or low charge protection switch.
Alldata information website
Thanks for reply, I charged with Robinair station. Two different ones. I will try adding a couple more ounces of Freon and let you know thanks.
I added more Freon ,did not help. I talked to someone at ford, Lincoln t/c ,grand mark & crown-vic all have a/c issues.cars were designed wrong.only fix is ford makes a low pressure cycle switch.##4W1Z-19E561-AA ,also crosses to a napa ##Tem207771 on Echlin RPS608.I am going to try switch. will let you know, Thanks
A/C switch from NAPA fixed problem, A/C vent temp is 40 deg at any speed
Thanks for getting back to us, this information will be very useful to other readers. Thanks for your input.