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HVAC Compressor + Coolant Fan Operation

Old Nov 19, 2022 | 08:34 PM
  #46  
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Re: HVAC Compressor + Coolant Fan Operation

It's possible that it measured all avaliable paths but it appears that the solid state device resistance is high enough that between A&C is 17K ohms (variable) and across A&B and C&B is 400kohms. To truly isolate it yeah, would have to cut then since they're hardwired. I have power supplies at work, if I don't get one I'll test it when I go back.
Old May 10, 2026 | 05:02 PM
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Re: HVAC Compressor + Coolant Fan Operation

I finally got around to it and finished this factory AC install on the 1994 1LE that didn't have factory AC. It's currently cooling to 45°F - 48°F at the vents while driving on the highway. At 60% humidity it's approximately 35psi on the low side and 260psi on the high side. All the wiring and splicing into various systems was interesting and helped me learn the form, fit, and function of the system.

I went from no AC, 1 big cooling fan, 1 cooling fan relay, to 2 smaller cooling fans, 3 fan relays, and an AC Clutch relay. Then of course the pressure sensor, evaporator temperature sensor install (stabbed into the fins and epoxied to them right in the center of the core per FSM location). It's great to have a cool cabin (no tinted windows yet) driving down the road for the first time in 28 years.

I have a question about SCAN9495 that I may have missed: Does the "AC Clutch" circuit ever show green and go from (0) to (1) like the status and command sections? I was wondering if I missed a splice or something, because I have S105 done. I also need to dig in a little closer to the vacuum system and make sure all the inlets/outlets are working properly, hopefully no duct leaks as well.

Never too late lol

Old Yesterday | 12:08 AM
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Re: HVAC Compressor + Coolant Fan Operation

Let’s try @GaryDoug
Old Yesterday | 12:15 PM
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Re: HVAC Compressor + Coolant Fan Operation

Originally Posted by Injuneer
Let’s try @GaryDoug
Thsnks Fred.

This is the one I'm curious about, if it's functional and reads off D8, or B21 to the PCM?

[Edit] clarifying if ac clutch is signaled to D8 or B21 for SCAN9495.


These two are functional and go "green" and from (0) to (1).



I verified all my vscuum valves seem to be fully opening and closing, and smoother the more they're used.

Tinted windows and suspension refresh is next.

Last edited by 1994-LT1-Eric; Yesterday at 06:39 PM.
Old Yesterday | 12:24 PM
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Re: HVAC Compressor + Coolant Fan Operation

This is how the evaporator temperature sensor mounting happened lol.










Old Yesterday | 01:41 PM
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Re: HVAC Compressor + Coolant Fan Operation

Can you clarify what exactly are you asking? There is no ac clutch item in the status section of the engine data, only in the inputs and outputs sections. Are you referring to the electrical faults section?,
Old Yesterday | 06:32 PM
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Re: HVAC Compressor + Coolant Fan Operation

Originally Posted by GaryDoug
Can you clarify what exactly are you asking? There is no ac clutch item in the status section of the engine data, only in the inputs and outputs sections. Are you referring to the electrical faults section?,
I'm asking if the AC Clutch relay table of SCAN9495 is supposed to turn "green" and "0" to a "1" when the AC clutch relay is energized?

When I run SCAN9495 on my car, it never turns green or goes to "1", like the other 2 (AC clutch status* & AC request)
Old Today | 12:30 AM
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Re: HVAC Compressor + Coolant Fan Operation


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