AC Not turning on

[GennyBenny]

Hello all, I have a 2015 5.0 and the AC will not turn on. There is refrigerant in the system (80 PSI, 64 F) and the compressor fuse (I think I got the right one, 10 amp - top passenger side) does not appear to be blown. Is there anything odd that would keep the AC from kicking on? I'm going to check to see if defrost will kick it on, then climb underneath and see if the clutch/coil are getting a signal and working. This car was owned in southern California before I got it so I assume the AC was ran basically all year.

 

[GennyBenny]

Okay so the fuse in the engine bay is getting power, not sure about the one by the drivers seat, but the fuse is good. Anyone know which fuse actually runs to the compressor? I'm guessing bad clutch. Under the car I go! Tomorrow...

 

[glennk]

When you turn on the A/C, do the cooling fans in front of the engine turn on?

 

[GennyBenny]

When you turn on the A/C, do the cooling fans in front of the engine turn on?

Not that I can tell. Does the fan come on with the AC button or pressure? I've seen it both ways in cars. My last truck was like that, only if the pressure was high enough.

 

[Kraig Wilkinson]

Not that I can tell. Does the fan come on with the AC button or pressure? I've seen it both ways in cars. My last truck was like that, only if the pressure was high enough.

If no power to ac clutch , check binary psi switch. Power in and power out.

 

[GennyBenny]

If no power to ac clutch , check binary psi switch. Power in and power out.

I'll check the switch while I'm down there. Is it a make or break on low/high pressure switch?

 

[Kraig Wilkinson]

I'll check the switch while I'm down there. Is it a make or break on low/high pressure switch?

Not sure with these cars. Some where on this forum you can download shop manual ! Keep us posted, for I too have a 15 5.0.

 

[Kraig Wilkinson]

Not sure with these cars. Some where on this forum you can download shop manual ! Keep us posted, for I too have a 15 5.0.

I suppose you will know more tomorrow. Power to clutch and not working ? Well sounds to me like you know what would be next. Good luck fellow 5.0 owner!

 

[GennyBenny]

I suppose you will know more tomorrow. Power to clutch and not working ? Well sounds to me like you know what would be next. Good luck fellow 5.0 owner!

I haven't checked the power at the compressor yet, need more light to do that tomorrow, but both the A/CON fuses are good and getting power. No warnings or anything so probably not an issue in the software???
Hyundai refers to it as a pressure sensor so it may send the actual pressure back to the module. If it has a bad signal it would definitely keep the AC from running.
Thanks, I'll keep you guys updated.

 

[Kraig Wilkinson]

I haven't checked the power at the compressor yet, need more light to do that tomorrow, but both the A/CON fuses are good and getting power. No warnings or anything so probably not an issue in the software???
Hyundai refers to it as a pressure sensor so it may send the actual pressure back to the module. If it has a bad signal it would definitely keep the AC from running.
Thanks, I'll keep you guys updated.

Yes that could be correct. I am not to savy with computers. But ac systems I know. That is probably right about sending psi reading back to ecm?

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[GennyBenny]

The pressure sensor seems to be fine, it's outputting about 1 volt for 65 PSI which is pretty close to spec. Guess I have to go underneath and check the clutch coil next.

 

[Kraig Wilkinson]

The pressure sensor seems to be fine, it's outputting about 1 volt for 65 PSI which is pretty close to spec. Guess I have to go underneath and check the clutch coil next.

Nice trouble shooting!

 

[GennyBenny]

Clutch coil is 13 Ohms. Sounds a bit high but I don't know what the spec is.
I'm getting a friend over to watch the compressor when I hit the button. I think I hear a click but not sure if it's the compressor or a relay.
I can't turn the compressor by hand, but that may just be because of an awkward angle. I hope it's not a seized compressor, that's gonna be pricey...

 

[Kraig Wilkinson]

Yeah it will.

 

[GennyBenny]

Actually, I'm wondering if the two wires on the compressor are actually for the clutch. From pictures of the compressor the wires go to the back of the unit, not the front where the coil would be. So is just one of the wires for the coil and the other for something else? Neither has continuity to ground.

 

[Kraig Wilkinson]

Actually, I'm wondering if the two wires on the compressor are actually for the clutch. From pictures of the compressor the wires go to the back of the unit, not the front where the coil would be. So is just one of the wires for the coil and the other for something else? Neither has continuity to ground.

Maybe when clutch is engaged you will have a ground?

 

[Kraig Wilkinson]

Maybe when clutch is engaged you will have a ground?

Need wire diagram.

 

[GennyBenny]

Reading through the shop manual, it seems the compressor has two things going on. It has a clutch I think - you can see it in the disassembly images, but also an ECV, Electronic Control Valve, for the swash plate angle (changes displacement). One of the two wires has to be for the clutch I would think. But neither has conductivity to ground. So I dunno.
I imagine the ECV probably has a higher resistance that wouldn't show up on a conductivity meter, but the coil should light it up instantly. The coils I've seen have been a few Ohms, like 2 to 5.

And the shop manual of course doesn't have the pinout for that connector... urgh!

 

[Kraig Wilkinson]

Reading through the shop manual, it seems the compressor has two things going on. It has a clutch I think - you can see it in the disassembly images, but also an ECV, Electronic Control Valve, for the swash plate angle (changes displacement). One of the two wires has to be for the clutch I would think. But neither has conductivity to ground. So I dunno.
I imagine the ECV probably has a higher resistance that wouldn't show up on a conductivity meter, but the coil should light it up instantly. The coils I've seen have been a few Ohms, like 2 to 5.

And the shop manual of course doesn't have the pinout for that connector... urgh!

Maybe no clutch ? That is why you can not turn? I dont know either. I need to see compressor. Can you access ac machine? Then you could draw the system down to see how much freon you have? Just a thought.

 

[GennyBenny]

Okay so doing some reading reveals that there is no clutch coil at all. The compressor is always on but it does have a clutch looking thing they call a limiter. Probably so that when the compressor does seize it doesn't kill the belt. The ECV is likely controlled by a PWM signal, I might pull out my trusty o-scope to check that out.
I don't have a machine, but the next step after this is to take it to an AC shop. The static pressure is right on the money (doesn't mean squat with R-134a) but it's not even trying. On my gauges it does absolutely nothing. Zip. Nada. Nothing.