how to check A/C
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how to check A/C
I have a 1990 ford e-350, turned into a flat bed. A/C isn't working. heater and defrost work great. thinking it is a electrical problem. when i check the power with it on or off, and i check from the postive side of the battery to the lines coming in they both read hot like they are ground lines. shouldn't there be a hot line going to the unit??
Posting Guru
Joined: Mar 2005
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From: KY
Like Dave said. When you have no return to ground you will see voltage on both sides. Like a relay.
Jump the low pressure switch and see if the compressor kicks in. If it does let it run for a minute. If it cools good then you have a bad switch. If it doesn't then we will go from there.
I have done allot of AC work but see what you have before we go any deeper.
Jump the low pressure switch and see if the compressor kicks in. If it does let it run for a minute. If it cools good then you have a bad switch. If it doesn't then we will go from there.
I have done allot of AC work but see what you have before we go any deeper.
Lead Driver
Joined: Nov 2003
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From: Campbell River, B.C.
With the engine off, you can simply turn the compressor by hand as fast as you can to see if there is anything left in the system. You should hear a faint hissing sound coming from the orifice tube. The orifice tube is located at the bottom of the air box near the passenger side valve cover.
If you are able to get it to cycle while the engine is running, pay close attention to temperature of the two refrigerant lines on the compressor. One should get cold, the other should be warm, but not hot enough to hurt your hand. If it gets hot, disable the system immediately.
If you are able to get it to cycle while the engine is running, pay close attention to temperature of the two refrigerant lines on the compressor. One should get cold, the other should be warm, but not hot enough to hurt your hand. If it gets hot, disable the system immediately.
Lead Driver
Joined: Mar 2006
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From: western SD
The low pressure switch is in the suction side of the system, the big hose. On the
f series it is on the dryer, the big can looking thing with the AC tubes running to it located by the heater box. The switch screws into the tube. You can unplug the electrical connector and just jump the wires. If it runs but does not cool low freon charge. To run a hot wire to the clutch leave the low pressure swith pluged in to check. Hope this helps. Tom
f series it is on the dryer, the big can looking thing with the AC tubes running to it located by the heater box. The switch screws into the tube. You can unplug the electrical connector and just jump the wires. If it runs but does not cool low freon charge. To run a hot wire to the clutch leave the low pressure swith pluged in to check. Hope this helps. Tom
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checking a/c
thanks that did help. jumped across the low pressure and it worked perfect. used a screw driver to see if there were any feon. none, so i guess its time to have it checked for a leak or just low..thanks for all the help....
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