Is my air conditioning blowing cold enough?

[dearchristopher]

I am going to have to look into that, I think mine is turning on often.

The jumper test is real simple cause they’re 2 wire switches. Paper clip or scrap wire will make it easy to test.

Mine was cycling on and off every 2-3 minutes so the compressor never ran long enough to keep the air properly cold. It was hitting the pressure shutoff before it could do any good.

Now, I freeze. I can get it cold enough to turn the air down to the first speed on a 95 degree southeast Texas day if I drive it long enough. Huge win!

 

[BC Moto]

Where did yu get the replacement switch? Have a part number by chance? If I get time this week I will try and Jump it

 

[ColoJeep]

Where did yu get the replacement switch? Have a part number by chance? If I get time this week I will try and Jump it

15 minutes to test , even if you're real slow.

 

[dearchristopher]

Where did yu get the replacement switch? Have a part number by chance? If I get time this week I will try and Jump it

https://www.amazon.com/dp/B00FY624AY?tag=wranglerorg-20

here is the exact part i used. at this price i might just order another one to have on the shelf.

i did have to cut my factory harness, but theres enough wire that you can do so without really hurting anything. it can always be wired back in easily. I extended the wires i cut, put on some insulated crimp connectors, and rock & roll. no adjustment needed. this switch is rated for r-12, so you might want to dig for an r-134 one, but from my research it didnt really matter. the pressure is the pressure. ive ran this one for around 5 months with zero issues. i did a 700 mile road trip to austin and back in the middle of august, and it never froze over or had any issues. i was ice cold the whole time.

 

[KennethS]

So I used the vacuum pump on the A/C system and It held vacuum and I ran the pump for an hour and it sat for another hour for leaks but it was solid. I then proceeded to fill the system and it seems to blow cold but this is with the temp gauge in the center vents. It seems like it could get better than this...

When you say "fill the system" how did you determine the system was full? Is it possible it just needs a bit more refrigerant?

Also, what was the outside temperature when you had that center vent thermometer reading? If the ambient temperature was much over 90, it's possible that was within spec for the ambient temperature per the chart in the factory manual.


https://wranglertjforum.com/attachments/1999-tj-service-manual-pdf.14034/

 

[Steel City 06]

If you want stupid cold, switch to a hydrocarbon refrigerant.
8 oz of R290/600a blend will outperform a normal charge of R134a and be significantly more energy efficient.

I used this:
https://www.duracool.com/shop/durac...z-can-with-trigger-hose-and-gauge-attachment/
Contains the exact amount we need for a TJ assuming you pull a vacuum before charging.

An adjustable low pressure switch helps with tuning.

The only caveat to hydrocarbon refrigerants is that they are flammable (R290 is literally propane, R600a is literally isobutane), so there is a slightly increased risk of fire in a collision or AC line rupture.

 

[dearchristopher]

If you want stupid cold, switch to a hydrocarbon refrigerant.
8 oz of R290/600a blend will outperform a normal charge of R134a and be significantly more energy efficient.

I used this:
https://www.duracool.com/shop/durac...z-can-with-trigger-hose-and-gauge-attachment/
Contains the exact amount we need for a TJ assuming you pull a vacuum before charging.

An adjustable low pressure switch helps with tuning.

The only caveat to hydrocarbon refrigerants is that they are flammable (R290 is literally propane, R600a is literally isobutane), so there is a slightly increased risk of fire in a collision or AC line rupture.

Going boom is the only thing that stops me from doing this

 

[BC Moto]

When you say "fill the system" how did you determine the system was full? Is it possible it just needs a bit more refrigerant?

Also, what was the outside temperature when you had that center vent thermometer reading? If the ambient temperature was much over 90, it's possible that was within spec for the ambient temperature per the chart in the factory manual.


https://wranglertjforum.com/attachments/1999-tj-service-manual-pdf.14034/


View attachment 644793

I have gauges that I use with the vacuum system and outside temp was 75 while taking the reading from the vent

 

[Steel City 06]

Going boom is the only thing that stops me from doing this

I won't say the risks are zero (they are not) but I will argue they are very low.

8 oz is half that of the standard green propane canister. With the system off, less than half of that is actually inside the cabin. When on, that value is even lower.

Meanwhile, a single can of computer duster has a 12oz charge of flammables. Even a 11oz can of hair spray has 4-6 oz of flammable gases. So just one can of hairspray has more flammables than would be present in the cabin at any time.

I did do the math a while back for the TJ, and in order to approach the LEL with the system running (high fan speed) and windows closed, the entire contents of the system have to leak out of the evaporator in less than 8 minutes. (Note an evaporator leak of that rate is exceptionally unlikely, especially given the evaporator is on the low pressure side.) With the vehicle stopped and no fan, it would actually exceed the UEL, but you would know something was wrong as soon as you opened the door and smelled the mercaptan.

An under-the-hood leak theoretically could ignite, but there is no confined space to create an explosion. In addition, with the CFM provided by the clutch fan unengaged at idle and the vehicle at rest, it would need to fully dump in less than 3-4 minutes to hit the LEL. At higher fan or road speeds, it would only be possible to ignite by snapping off the high pressure line with the compressor on, and even then it would be a quick flash only if it can find an ignition source in the very short time that exists before it gets diluted and blown out under the car.

For yet another comparison, a ruptured fuel line would spray out 8 oz of fuel every 5 seconds. (And you have up to 1,800 oz of fuel onboard versus just 8 oz of refrigerant...)


Another thought: In Canada, hydrocarbon refrigerants are the only ones you can legally buy for automotive ACs. Meaning every can sold in an auto parts store there is this stuff. (Yet I don't hear too much about how Canadian cars tend to explode more...)

 

[dearchristopher]

I won't say the risks are zero (they are not) but I will argue they are very low.

8 oz is half that of the standard green propane canister. With the system off, less than half of that is actually inside the cabin. When on, that value is even lower.

Meanwhile, a single can of computer duster has a 12oz charge of flammables. Even a 11oz can of hair spray has 4-6 oz of flammable gases. So just one can of hairspray has more flammables than would be present in the cabin at any time.

I did do the math a while back for the TJ, and in order to approach the LEL with the system running (high fan speed) and windows closed, the entire contents of the system have to leak out of the evaporator in less than 8 minutes. (Note an evaporator leak of that rate is exceptionally unlikely, especially given the evaporator is on the low pressure side.) With the vehicle stopped and no fan, it would actually exceed the UEL, but you would know something was wrong as soon as you opened the door and smelled the mercaptan.

An under-the-hood leak theoretically could ignite, but there is no confined space to create an explosion. In addition, with the CFM provided by the clutch fan unengaged at idle and the vehicle at rest, it would need to fully dump in less than 3-4 minutes to hit the LEL. At higher fan or road speeds, it would only be possible to ignite by snapping off the high pressure line with the compressor on, and even then it would be a quick flash only if it can find an ignition source in the very short time that exists before it gets diluted and blown out under the car.

For yet another comparison, a ruptured fuel line would spray out 8 oz of fuel every 5 seconds. (And you have up to 1,800 oz of fuel onboard versus just 8 oz of refrigerant...)


Another thought: In Canada, hydrocarbon refrigerants are the only ones you can legally buy for automotive ACs. Meaning every can sold in an auto parts store there is this stuff. (Yet I don't hear too much about how Canadian cars tend to explode more...)

This is enough to convince me. What are your temps out of the vent?

 

[Steel City 06]

This is enough to convince me. What are your temps out of the vent?

Had the adjustable low pressure switch set a bit too low for this one...

This is on outside air intake and max blower speed with incoming air in the upper 70s with very high humidity. RPM and engine fan bumped up in speed to simulate normal driving. It could probably hold the low 30s even if it was 90...

The low pressure switch needs to be set such that the compressor cycles before the evaporator gets this cold and starts to freeze up. But tuning to hold 40-45° is definitely feasible, even with intake temperatures at 90° or higher.