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AC questions and opinions

Husker6.5

135' diagonal 16:9HD, 25KW sound!
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Yeah, Hell's Back Porch is June, July August in the Hill Country around Killeen, after any time it rains and the humidity goes to 90% and the temperature hovers around 100°!
 

GM Guy

Manual Trans. 2WD Enthusiast
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I don't like those repair kits and the stock 95 condenser was a serpentine capillary ribbon design that was crap for r134 to begin with. I would install a high pressure cutout switch at the condenser and install the purple compressor mounted switch to trigger your evc. 325 psi on and 225 off is a bit on the high side to run your high side pressures. The purple switch closes at 283 and opens at 210. There is also one that closes at 240 but it doesn't open until 150.

Ferm, what design was the factory 94-95 Suburban? They looked quite a bit different than the trucks. I went ahead and snagged a pair last time I was in the pick and pull yard up near the Idaho farm (3 great pull yards within 40 miles, versus one yard local that is overpriced here in KS, so I hit them whenever I'm out :) ). Looking on Rockauto if a guy was to buy new they are identical PN, but the factory Harrison units are quite different SUV to truck when comparing, both in thickness and tube routing. The fins are coarser as well, which I think would be beneficial to 6.5L cooling.

I dont know shit about the system designs, but my uneducated thought was it would bump system performance slightly on my crew cab 95 that needs a flush anyways ( bad compressor knocking), so I figured I might swap. I grabbed ythe rubber mounts as well, Im hoping the core supports have the same dimensions on the lower rubber mount retainer so it will drop in with no modding.
 

THEFERMANATOR

FRANKENBURBAN
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Ferm, what design was the factory 94-95 Suburban? They looked quite a bit different than the trucks. I went ahead and snagged a pair last time I was in the pick and pull yard up near the Idaho farm (3 great pull yards within 40 miles, versus one yard local that is overpriced here in KS, so I hit them whenever I'm out :) ). Looking on Rockauto if a guy was to buy new they are identical PN, but the factory Harrison units are quite different SUV to truck when comparing, both in thickness and tube routing. The fins are coarser as well, which I think would be beneficial to 6.5L cooling.

I dont know shit about the system designs, but my uneducated thought was it would bump system performance slightly on my crew cab 95 that needs a flush anyways ( bad compressor knocking), so I figured I might swap. I grabbed ythe rubber mounts as well, Im hoping the core supports have the same dimensions on the lower rubber mount retainer so it will drop in with no modding.
My 95 Suburban had the serpentine style that used the flat capillary set-up. I know later years went to a parallel flow design as my 99 Tahoe had one in it.

And for the most part, sub's and pickups got the same condensers. GM came to there senses for the gmt800's and put in a bigger condenser for dual air unit than single air units came with.
 

DieselAmateur

Diesel or Bust
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Forgive me for not knowing squat about a/c systems and trinary switches and whatnot, but I'm a bit confused about where to source a trinary switch and how/ where to install it in a 6.5

In watching the video in the other thread, a trinary switch apparently has 4 wires. Yet both the compressor and condenser switches only have 2 wires each. Are these used combined as the 4 wires of said trinary switch? Does it matter which of the 2 wires going to the compressor and condenser is spliced into? I have the parts for the electric fan clutch conversion and would love to add this feature too, but an electrical novice like me needs a kids- level coloring book diagram for situations like this.

also @THEFERMANATOR , I see you recommend the purple color compressor mounted switch, what color/ pressure parameters do you recommend for the condenser switch? I only see a light green and dark green color switch for the condenser offered on RockAuto (for my '95 at least) and no pressure specs are given for the dark green one
 

THEFERMANATOR

FRANKENBURBAN
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Forgive me for not knowing squat about a/c systems and trinary switches and whatnot, but I'm a bit confused about where to source a trinary switch and how/ where to install it in a 6.5

In watching the video in the other thread, a trinary switch apparently has 4 wires. Yet both the compressor and condenser switches only have 2 wires each. Are these used combined as the 4 wires of said trinary switch? Does it matter which of the 2 wires going to the compressor and condenser is spliced into? I have the parts for the electric fan clutch conversion and would love to add this feature too, but an electrical novice like me needs a kids- level coloring book diagram for situations like this.

also @THEFERMANATOR , I see you recommend the purple color compressor mounted switch, what color/ pressure parameters do you recommend for the condenser switch? I only see a light green and dark green color switch for the condenser offered on RockAuto (for my '95 at least) and no pressure specs are given for the dark green one
A trinary switch does 3 things, it provides low pressure shut down(opens around 40 psi), it also provides high pressure shutdown (opens around 425-450), and they also provide an output to control electric fans(generally come on around 225-250). 2 wires are for the compressor control and the other 2 are for the fan control.

The condenser mounted switch is a green one, that's it, and it closes around 325 psi, and reopens around 250 psi. The purple compressor mounted switch is generally used for controlling aux electric fans, it closes at 283 and reopens around 210. There is a different compressor mounted switch used for primary electric fan control(don't recall the color off the top of my head right now).
 

DieselAmateur

Diesel or Bust
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Thanks as always for sharing the knowledge Ferm. Is there a schematic anywhere for wiring this? I get the gist of a trinary switch but still have zero clue as how to make it all work on a stock 6.5 setup.

Or is a better question what acts as the binary switch on a stock 6.5 and what needs to be done to make it into a trinary? Not a pressing issue for me at the moment as we're heading into winter here in the northeast and won't need A/C anytime soon, but this is the time when I'll actually have time to wrench and I'll finally get around to the electric fan setup probably sometime in february ahah
 

MrMarty51

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I looked over the wiring diagram. There is one of the wires that can be hooked to the compressor power wire.
I thought that was for to turn on the fan when the compressor fires up.
Is there a problem with wiring it up that way ?
 

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FRANKENBURBAN
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I looked over the wiring diagram. There is one of the wires that can be hooked to the compressor power wire.
I thought that was for to turn on the fan when the compressor fires up.
Is there a problem with wiring it up that way ?
Some people wire it so the fan engages with the AC, but this will have your fan clutch locked in solid whenever your compressor is running, and that big fan can draw some power running for no reason. Installing a trinary switch or a high pressure activated switch is a much better option as it will only trigger the fan to lock in when your high side pressure is getting high, and it needs the fan to cool it down. It can save alot of load on your engine, not to mention the noise from the fan locked in for no reason running down the road.
 

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FRANKENBURBAN
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Thanks as always for sharing the knowledge Ferm. Is there a schematic anywhere for wiring this? I get the gist of a trinary switch but still have zero clue as how to make it all work on a stock 6.5 setup.

Or is a better question what acts as the binary switch on a stock 6.5 and what needs to be done to make it into a trinary? Not a pressing issue for me at the moment as we're heading into winter here in the northeast and won't need A/C anytime soon, but this is the time when I'll actually have time to wrench and I'll finally get around to the electric fan setup probably sometime in february ahah
Each trinary switch uses it's own wiring colors. They normally use 4 wires, 2 for the compressor side, and the other 2 for the fan control side. The factory system didn't use a trinary or even a binary switch. GM installed a high pressure cutout switch on r134 systems in the high side to shut the system off in case the condenser wasn't removing enough heat, a low pressure cycling switch in the low side to cycle the system, and 88-90 and 95+ had a switch in the high side to for e the system to inside air if the high side pressure got above a certain point.

I actually forgot all about the 88-90 systems pressure switch. It is a round compressor mounted style, but it closes and opens at a much lower pressure than the purple one.
 
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