A/C Problem
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A/C Problem
My A/c hasnt been working in my 98 F150, So I decided to check the pressure.
I only checked the low side port (on the receiver) and it read VERY high, it was in the "Alert" range of the gauge. The engine was running, 4.6. The gauge read somewhere around 120 psi.
What is wrong with my truck? What do I need to fix it?
Thanks
Mike
I only checked the low side port (on the receiver) and it read VERY high, it was in the "Alert" range of the gauge. The engine was running, 4.6. The gauge read somewhere around 120 psi.
What is wrong with my truck? What do I need to fix it?
Thanks
Mike
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From: St Louis
That is a completely normal pressure reading for a fully charged system with warm under-hood temps while the compressor is not running. Now you need to determine why the compressor isn't running.
Next easy check is the fuse. F5 in the underdash panel.
Next, locate and unplug the connector to the cycling switch on top of the accumulator can (the low side port is on the side of that can). Use a paperclip to jumper the pins of the connector (not the switch) and see if the compressor clutch pulls in and the system starts cooling. If so, replace the switch. No need to recharge the system, there is a Schraeder valve under the switch.
Try that. If jumpering the switch doesn't get it and the fuse is good, I'll pull up the diagrams tomorrow and give you some more homework.
Steve
Next easy check is the fuse. F5 in the underdash panel.
Next, locate and unplug the connector to the cycling switch on top of the accumulator can (the low side port is on the side of that can). Use a paperclip to jumper the pins of the connector (not the switch) and see if the compressor clutch pulls in and the system starts cooling. If so, replace the switch. No need to recharge the system, there is a Schraeder valve under the switch.
Try that. If jumpering the switch doesn't get it and the fuse is good, I'll pull up the diagrams tomorrow and give you some more homework.
Steve
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Alright The fuse is good, I jumpered the switch and still doesnt work.
The truck has 130k on it, so I'm thinking I need a new compressor. The compressor does nothing, doesnt spin, nothing.
What I noticed when we jumpered that connector is that the engine would rev higher when it was jumped.
Do i need a new compressor?
The truck has 130k on it, so I'm thinking I need a new compressor. The compressor does nothing, doesnt spin, nothing.
What I noticed when we jumpered that connector is that the engine would rev higher when it was jumped.
Do i need a new compressor?
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From: St Louis
Do i need a new compressor?
Let me look up the procedure in the morning.
What I noticed when we jumpered that connector is that the engine would rev higher when it was jumped.
Steve
Last edited by projectSHO89; Aug 20, 2006 at 09:34 PM.
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From: St Louis
Looked up the schematic.
The clutch is driven directly by the cycling switch. That suggests that there is either an open circuit to the clutch, the clutch coil is open, there is an open circuit for the clutch's ground, or the electrical circuit is fine but the clutch is not engaging, possibly due to excessive air gap or other clutch mechanical failure.
Start by making certain the clutch connector is securely plugged in.
Make a resistance check between the low side of the cyling switch (Black/yellow) and ground, should be around 6-10 ohms. If it's open, follow the suggestion above to isolate. If the correct resistance is there, the clutch probably has one of the possible mechanical faults. If the clutch hub has disintegrated, check for a locked compressor (see, we did get to it as a possibility).
Geez, how many places did you ask about this? I've seen your postings at leas three other places...
Steve
The clutch is driven directly by the cycling switch. That suggests that there is either an open circuit to the clutch, the clutch coil is open, there is an open circuit for the clutch's ground, or the electrical circuit is fine but the clutch is not engaging, possibly due to excessive air gap or other clutch mechanical failure.
Start by making certain the clutch connector is securely plugged in.
Make a resistance check between the low side of the cyling switch (Black/yellow) and ground, should be around 6-10 ohms. If it's open, follow the suggestion above to isolate. If the correct resistance is there, the clutch probably has one of the possible mechanical faults. If the clutch hub has disintegrated, check for a locked compressor (see, we did get to it as a possibility).
Geez, how many places did you ask about this? I've seen your postings at leas three other places...
Steve
Last edited by projectSHO89; Aug 21, 2006 at 08:41 AM.
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From: St Louis
Originally Posted by MZ89
Thanks alot for the help.
I put it on every F150 forum I'm apart of.
I put it on every F150 forum I'm apart of.
Just wondering if I missed any...FWIW, I only responded here since I already started this response...
Steve
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Is it the compressor clutch?
Ive been reading about somethings, and people have said it could be the compressor clutch. The whole compressor still spins freely, so I'm not sure.
What do yotu think?
Ive been reading about somethings, and people have said it could be the compressor clutch. The whole compressor still spins freely, so I'm not sure.
What do yotu think?
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From: St Louis
Originally Posted by MZ89
Is it the compressor clutch?
Ive been reading about somethings, and people have said it could be the compressor clutch. The whole compressor still spins freely, so I'm not sure.
What do yotu think?
Ive been reading about somethings, and people have said it could be the compressor clutch. The whole compressor still spins freely, so I'm not sure.
What do yotu think?
I can say that the problem is most likely either an electrical open in the clutch circuit or a mechanical failure of the clutch. A couple of simple ohmmeter checks and/or a visual inspection will pinpoint the fault.
I can suggest how to diagnose it, but it's not possible to do it for you over the internet.
Steve
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I had a similar problem where everything checked out but A/C just didn't work. The technicians at two different Ford dealers were stumped. I finally found the problem- the **** that controls the temperature had a slight crack in the area that slips over the metal shaft of the control. When the **** was turned the shaft of the control didn't and was therefor stuck in the hot position.
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From: St Louis
Originally Posted by crawdoogie
I had a similar problem where everything checked out but A/C just didn't work. The technicians at two different Ford dealers were stumped. I finally found the problem- the **** that controls the temperature had a slight crack in the area that slips over the metal shaft of the control. When the **** was turned the shaft of the control didn't and was therefor stuck in the hot position.
i think one test is to put 12 volts directly to the compressor and see if the clutch kicks in and out. you can even do that with the motor off. the clutch is just a magnetic coil with two ends + and -.
Steve