Intermittent A/C

[reDrocketofficial]

Hello fellow Explorers,


I've got a situation with my 2017 FPIU. The A/C went out a few months ago and I was certain it was the compressor. There is pressure in the system and the clutch was engaging when I jumped the relay (as well as testing with a known good relay). I was pretty set on replacing the compressor, just haven't gotten around to it yet when suddenly last week I let someone else drive it for a week and magically the A/C works again. Well, it worked. I drove it for a few days with the A/C working, which was great when I took a nap in the back after I showed up to work too early on a hot day.

Last night, it rained and as I was driving I could feel the A/C stop working. Is there something I'm not checking or is the issue something else that isn't the compressor? Or was it just luck that it kicked back in for a short time? Is there a relay or switch that isn't working properly, as I know when you drive at WOT it will turn off the A/C to prioritize power.

Any thoughts on this?

 

[Pete Deering]

Hello fellow Explorers,


I've got a situation with my 2017 FPIU. The A/C went out a few months ago and I was certain it was the compressor. There is pressure in the system and the clutch was engaging when I jumped the relay (as well as testing with a known good relay). I was pretty set on replacing the compressor, just haven't gotten around to it yet when suddenly last week I let someone else drive it for a week and magically the A/C works again. Well, it worked. I drove it for a few days with the A/C working, which was great when I took a nap in the back after I showed up to work too early on a hot day.

Last night, it rained and as I was driving I could feel the A/C stop working. Is there something I'm not checking or is the issue something else that isn't the compressor? Or was it just luck that it kicked back in for a short time? Is there a relay or switch that isn't working properly, as I know when you drive at WOT it will turn off the A/C to prioritize power.

Any thoughts on this?

Yes
1. Your first two test are spot on.
2. When you removed the relay and power relay contacts 87 or 87a( only one works).
That check the circuit and the low pressure switch.
NOW the AC does not work
Do it again steps 1&2. Hold the clutch closed , try too turn the clutch pulley. That check the gap for slippage.
If the clutch Closes and opens, That said that the cycling switch is good and you have a charge in the system.
3. Check the high pressure switch with a ohm meter. It should be closed. ( engine off).
4. Next step is too put your gauge manifold on and check the pressures.
5. Did you any work on the AC system?
With that person just driving it and the is work , you have a loose or bad connection,.
Just a note you need to use a test light when checking. A ohm Meter will read good. A test light will flash and go out.

 

[reDrocketofficial]

Yes
1. Your first two test are spot on.
2. When you removed the relay and power relay contacts 87 or 87a( only one works).
That check the circuit and the low pressure switch.
NOW the AC does not work
Do it again steps 1&2. Hold the clutch closed , try too turn the clutch pulley. That check the gap for slippage.
If the clutch Closes and opens, That said that the cycling switch is good and you have a charge in the system.
3. Check the high pressure switch with a ohm meter. It should be closed. ( engine off).
4. Next step is too put your gauge manifold on and check the pressures.
5. Did you any work on the AC system?
With that person just driving it and the is work , you have a loose or bad connection,.
Just a note you need to use a test light when checking. A ohm Meter will read good. A test light will flash and go out.

I haven't done any work on the system at all. NAPA sells the pressure inducers for about $55. There is no low and high pressure switch, there is a transducer on the high side that reads the pressure and the temperature off the evaporator.

I can probably replace it and see if it works, however, my thoughts are that the safety system won't allow the clutch to engage. But if I manually engage the clutch by jumping the relay, it should work and yet it doesn't.

 

[Pete Deering]

I haven't done any work on the system at all. NAPA sells the pressure inducers for about $55. There is no low and high pressure switch, there is a transducer on the high side that reads the pressure and the temperature off the evaporator.

I can probably replace it and see if it works, however, my thoughts are that the safety system won't allow the clutch to engage. But if I manually engage the clutch by jumping the relay, it should work and yet it doesn't.

If can engage the clutch than the safety switch are OK.
Maybe its the clutch air gap.
Turn the AC on with engine run is the AC compressor clutch running?
Your compressor probably has a valve internal. I don't have any experience with thise.
I believe I watch a video on them, n the FORDMAKULOC channel.

 

[reDrocketofficial]

If can engage the clutch than the safety switch are OK.
Maybe its the clutch air gap.
Turn the AC on with engine run is the AC compressor clutch running?
Your compressor probably has a valve internal. I don't have any experience with thise.
I believe I watch a video on them, n the FORDMAKULOC channel.

The clutch is engaging. It clicks when I jump the relay and it does engage if I try to turn it while the engine is off.

However, if I jump the clutch relay while the engine is running and the A/C is on, it won't cool.


The pressure in the system has to be correct because it did work again. So that means there's something else in the system like a switch or valve that isn't working. I may just end up taking it to a shop or a local dealer and letting them figure it out.

 

[DePolicify]

Remember that if the system is not properly charged then the AC will not cycle on to prevent damaging the system.

 

[reDrocketofficial]

Remember that if the system is not properly charged then the AC will not cycle on to prevent damaging the system.

I understand that but it should kick on by bypassing the safety system. And it did work again for a week, so the charge had/has to be correct.

 

[peterk9]

As another member mentioned, it could be a loose connection somewhere in the system.

Peter