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HDGENE
HDGENE, Ford Senior Master/Diesel/Trans
Category: Ford
Satisfied Customers: 4919
Experience:  25 years Auto experience, Ford ,GM, Chrysler, Asian & European
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Expedition xlt: I have a 2007 expedition that the ac compressor

Customer Question

I have a 2007 expedition that the ac compressor will not come on. Took it to midas and they said the refrigerant is full and that they thought it was either the expansion valve or control unit. Since this has the rear ac as well how do I know which to replace if the compressor won't come on.
Submitted: 1 year ago.
Category: Ford
Customer: replied 1 year ago.
If I remember correctly it blew cold when I had the jumper wire on but after a few minutes it over pressurized and the blow off valve opened.
Expert:  HDGENE replied 1 year ago.
Hello, so the compressor doesnt come on unless you jump it?Then it blows the blow off valve? You are jumping it at the low cycling switch?
Customer: replied 1 year ago.
Not sure which side I'm jumping. I pulled the fuse out and jumped it but there are about 5 pins and I don't have a schematic so I'm not sure which side I jumped. I assumed the blow off valve went because it wasn't cycling on and off with the jumper
Expert:  HDGENE replied 1 year ago.
If you have power and ground to the compressor clutch and it wont come on, then the clutch coil is no good. If you dont have power and ground to the coil then there may be a fault with the low pressure cycling switch(if equipped on this system) Assuming the system has a full charge.The ac power relay supplies power for the clutch coil.
Customer: replied 1 year ago.
Where would I check the voltage? At the fuse? Would expansion valves cause it not to come on?
Expert:  HDGENE replied 1 year ago.
No the expansion valve would freeze up the system it isnt electrical. At the compressor coil two wire connector
Customer: replied 1 year ago.
I checked the plug that plugs into the compressor.....I have continuity for the ground side but not voltage on the power side
Customer: replied 1 year ago.
Where would the low pressure cycling switch be located
Customer: replied 1 year ago.
Installed jumper wire across the low pressure cycling switch pins and ac compressor did not come on. How would I check the knob on the dash to see if it is working
Expert:  HDGENE replied 1 year ago.
Do you have power at the cycling switch?
Customer: replied 1 year ago.
5 volts on 2 pins and one that has intermittent continuity to a ground
Customer: replied 1 year ago.
If I check pin to pin....the 2 with 5 v is constant when checked across the ground pin
Expert:  HDGENE replied 1 year ago.
Is this manual or automatic climate control? Does it have auxillary heat and ac?
Customer: replied 1 year ago.
Manual....and if auxiliary means rear heat and a/c then yes
Customer: replied 1 year ago.
If I turn the rear on I hear clicking behind the panel.....I was told that was the door motor gear stripped that moves from hot to cold
Customer: replied 1 year ago.
The plug behind the fan speed control in the dash looks like it has melted where the pin connected to the gray with brown stripe wire connects
Expert:  HDGENE replied 1 year ago.
you should have battery voltage coming out of the ac relay directly to the ac compressor when the pcm grounds the relay not 5 volts. The violet/white wire to the compressor coil.
Customer: replied 1 year ago.
If jumped at the relay the compressor comes on.....the low pressure switch only has 5 v on 2 pins.....if I apply 12 v to either pin nothing happens
Customer: replied 1 year ago.
The plug that looked melted only goes to the blower so it's not relevant.....blower still functions in all ranges.....what would keep the relay from closing the circuit to the compressor.....would that be before or after the low pressure switch on the schematic.....would anything for the rear a/c keep it from working
Expert:  HDGENE replied 1 year ago.
Failed relay, low or overcharged ac system pressures. Powertrain control module failure(not grounding the relay or wiring between the pcm and ac relay)
Customer: replied 1 year ago.
There are 2 pins in the relay that have continuity to a ground....1 has 23 ohms resistance and the other has 46 ohms resistance
Expert:  HDGENE replied 1 year ago.
Pin 2 & Pin 3 at the relay should have battery voltage. Pin 5 goes to the compressor . pin 1 is grounded by the pcm
Customer: replied 1 year ago.
What color wire behind the dash goes to the ac button to tell it I want it on.....I'm going to test voltage there and make sure it's being told to come on.....I'm have Chilton manual but the schematic doesn't have all of the wires
Expert:  HDGENE replied 1 year ago.
You really need a scan tool to monitor the ac demand from the climate control switch and monitor the evap temperature sensor. If the evap temp sensor reads 40 below zero it will never turn the ac compressor on.