Engine AC compressor stays running?

91GTstroked · Apr 28, 2020

Okay guys,

I have some other things to try and fix. Here's the deal. I have a mark iv electric fan with a painless relay.

Once the fan turns on at 180* my AC compressor starts running. It does this with the ac controls turned off!

I noticed this because my ac lines get frost on them without actually turning on the AC.

Just bought the car last May, so trying to figure things out.

Thanks.

91GTstroked · Apr 29, 2020

Also, can I just disconnect the wiring harness to the ac compressor if I don't want it to run?

The car has the painless 30103 relay.

Fan Relay w/thermostatic switch 185 degrees On/175 degrees Off Part No 30103

This kit includes: SPST 40 Amp relay 30 Amp circuit breaker Thermostatic switch 185°F On/175°F Off (thread size: ⅜"-18NPT) ½"NPT to ⅜"NPT adapter Relay base with harness (6' input, 4' output) Crimp-on terminals Mounting

www.painlessperformance.com

General karthief · Apr 29, 2020

I'm going to jump in here and say look at the wiring that turns on the fan when you turn on the ac, something is likely hooked up wrong.
Someone will jump in here now, I usually give bad advice and they follow me around and correct it.

Adieu · Apr 29, 2020

General karthief said:
I usually give bad advice and they follow me around and correct it.

CT!

91GTstroked said:
Okay guys,

I have some other things to try and fix. Here's the deal. I have a mark iv electric fan with a painless relay.

Once the fan turns on at 180* my AC compressor starts running. It does this with the ac controls turned off!

I noticed this because my ac lines get frost on them without actually turning on the AC.

Just bought the car last May, so trying to figure things out.

Thanks.

Is the defroster turned on when this is happening?

91GTstroked · Apr 29, 2020

74stang2togo said:
CT!

Is the defroster turned on when this is happening?

No all controls are off.

Noobz347 · Apr 29, 2020

74stang2togo said:
CT!

General karthief said:
Someone will jump in here now, I usually give bad advice and they follow me around and correct it.

Sometimes I do it 'intentionally' because I can't remember something and can count on the internet to go:

"HA! I KNEW YOU WERE AN IMBECILE! Here's the CORRECT answer..."

Me:

KRUISR · Apr 29, 2020

Does the compressor turn off again when the fan does. If so, you likely have the signal from the AC to your fan controller hooked up wrong.

Not sure how you have it hooked up so hard to diagnose.

91GTstroked · Apr 29, 2020

KRUISR said:
Does the compressor turn off again when the fan does. If so, you likely have the signal from the AC to your fan controller hooked up wrong.

Not sure how you have it hooked up so hard to diagnose.

I believe it does. It's set at one fan speed. Turns on at 180 and stays running. I can manually shut fan off.

I can't figure out why they have it wired like that. I rarely ever use AC.

KRUISR · Apr 29, 2020

Does your fan shut off on its own or do you need to turn it off to get it to stop?

General karthief · Apr 29, 2020

@74stang2togo my ct is just fine!!
And yes, you prolly could pull the connector from the ac pump till you figure it out, just make sure the fan still comes on when it is supposed to.

Adieu · Apr 29, 2020

General karthief said:
my ct is just fine!!

Oooh! CT!!!

91GTstroked · Apr 29, 2020

KRUISR said:
Does your fan shut off on its own or do you need to turn it off to get it to stop?

Its connected to the factory fog light switch. So I can turn it off.

91GTstroked · Apr 29, 2020

So I disconnected the ac compressor harness. Fan turns on and stays running like it should.

Then I look further down on the wiring. It appears someone connected a red wire to it. Not sure why they want the compressor running full time?

Either way, should I disconnect it? I might leave the whole thing unhooked for now. I never use the AC. Maybe delete it at some point.

Adieu · Apr 29, 2020

91GTstroked said:
So I disconnected the ac compressor harness. Fan turns on and stays running like it should.

Then I look further down on the wiring. It appears someone connected a red wire to it. Not sure why they want the compressor running full time?

Either way, should I disconnect it? I might leave the whole thing unhooked for now. I never use the AC. Maybe delete it at some point.

They probably cross-connected it like that to bypass the safety switch due to either the switch or another component being bad. That was a bad idea on their part, because if the pressure in the system gets too high, you can have an explosion (though usually no fire unless the PAG oil hits the headers), and if it drops too low, the compressor can catastrophically lock up due to no oil circulation.

On a side note, @General karthief should be happy now.

91GTstroked · Apr 29, 2020

74stang2togo said:
They probably cross-connected it like that to bypass the safety switch due to either the switch or another component being bad. That was a bad idea on their part, because if the pressure in the system gets too high, you can have an explosion (though usually no fire unless the PAG oil hits the headers), and if it drops too low, the compressor can catastrophically lock up due to no oil circulation.

On a side note, @General karthief should be happy now.

Makes sense. I just disconnected the red wire, hooked the harness back up to the compressor. AC blows cold, and the compressor cycles on and off, which I believe it's suppose to when I have the AC turned on. Stays off if the control is off.

Maybe I'll delete that red wire.

jrichker · Apr 29, 2020

Some help for you to see how it is supposed to be wired...
Click on the drawing to enlarge it for easier viewing...

5.0 wiring diagram for Fuel Injectors, Sensors, and Actuators

General karthief · Apr 29, 2020

74stang2togo said:
On a side note, @General karthief should be happy now.

Happy about what?
Did I get something right?
Nevermind, I see now.

Engine AC compressor stays running?

91GTstroked

91GTstroked

Fan Relay w/thermostatic switch 185 degrees On/175 degrees Off Part No 30103

General karthief

wonder how much it would cost to ship you a pair

Adieu

Easy there, this ain't a dating site.

91GTstroked

Noobz347

Stangnet Facilities Maint Tech... Er... Janitor

KRUISR

91GTstroked

KRUISR

General karthief

wonder how much it would cost to ship you a pair

Adieu

Easy there, this ain't a dating site.

91GTstroked

91GTstroked

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wonder how much it would cost to ship you a pair

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wonder how much it would cost to ship you a pair

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