AC Cutting Out-- Long

[Riley]

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I'm now having a similar problem but not exactly. My AC works in the morning for anywhere from 5 to 15 minutes. After that it will never work again until the next day.

The dashboard temp sensor is reading just below 1/2 half way (niddle width). Doesn't seem to be overheating.

I'm about to just pull the connector on the sensor to test this theory.

I gather that it's the middle sensor, can anybody give a better location or pic?

Anybody know the ballpark price of the sensor?

Thanks

R

 

[ShottsUZJ100]

Sorry to resurrect a long dead thread, but I figured I would finish the story in case anyone ever reads this thread. To recap, last fall the AC was cutting off when the engine warmed up.

After trying a bunch of different things I was able to determine it was the AC coolant sensor that was turning off the AC. I figured this out by pulling the sensor connector and observing that the AC compressor started back up-- and it could be stopped by reconnecting the sensor.

I then tested the sensor by deep frying it in canola. During this process I accidently cooked it to almost 300 degrees. This actually fixed the problem. After this cooking the sensor appeared to turn on and off at the right temperatures. I reinstalled it, and there was no more AC cutting out.

Because I was not sure if I really fixed the sensor --in theory I could have just broke it-- I ordered a new one from CDAN.

A couple of days ago (months later) I finally got around to replacing the sensor. The problem remained fixed-- so I must not have been overheating, it was a sensor problem all along.

Conclusions-- 1) those AC coolant sensors do go bad. 2) It is easy diagnose-- just pull the connector when it has shut off and see if it starts back up (of course, actual overheating will cause the same result) 3) you might be able to fix your sensor by heating it to 300 degrees.

Jared

PS--Anyone want to buy a used AC coolant temperature sensor? Served medium well.

Thanks for your hard work. I'll have my '97 checked. When I'm at a drive-thru or on a slow (near stopped or stopped) 4WD trail, the A/C kicks out and in every 1-2 minutes. If we keep miving we're fine. The temp gauge shows normal. The truck runs great. The A/C was just recharged as a precaution...prob still exists. I bet it could be a bad switch.

 

[Tools R Us]

Low airflow and hot weather can cause the A/C system to overheat driving up the head pressure, the pressure switch turns off the compressor until the pressure comes down to spec. An overcharged system will make it worse, an electric pusher fan will eliminate the problem and give lower vent temps at slow speeds.

 

[ShottsUZJ100]

Low airflow and hot weather can cause the A/C system to overheat driving up the head pressure, the pressure switch turns off the compressor until the pressure comes down to spec. An overcharged system will make it worse, an electric pusher fan will eliminate the problem and give lower vent temps at slow speeds.

Though in 3 years my '93 has never done this...even once. ???? I just had th system re-charged and checked. ????

 

[Tools R Us]

Though in 3 years my '93 has never done this...even once. ???? I just had th system re-charged and checked. ????

The '93 wasn't black! Is the '93 R12 or R134?

The way to tell is, hookup the gauges and let the truck idle in the sun when it's hot, watch the high side gauge, if the compressor is cutting off when the gauge reads about 450, that's your problem. There are two ways to fix the problem, remove a little R134 until it doesn't cycle, and/or add a fan for more air flow. Adding the fan will lower your A/C vent temps when idling at AZ temps.

 

[ShottsUZJ100]

The '93 wasn't black! Is the '93 R12 or R134?

The way to tell is, hookup the gauges and let the truck idle in the sun when it's hot, watch the high side gauge, if the compressor is cutting off when the gauge reads about 450, that's your problem. There are two ways to fix the problem, remove a little R134 until it doesn't cycle, and/or add a fan for more air flow. Adding the fan will lower your A/C vent temps when idling at AZ temps.

R12

You think the black maters?

 

[Gieser]

The '93 wasn't black! Is the '93 R12 or R134?

up to 5/93 is R12, after is R134 in what I have seen.

 

[Tools R Us]

R12

I have found R12 to be more stable at high temps, delivering lower vent temps and more forgiving if your slightly off on the charge and/or setup. R134 requires more precision, the charge needs to be dead on for the conditions. In our HOT conditions the factory recommended charge may need some fine tuning, slightly less charge to be happy. The lower charge may produce higher vent temps. So the other way to fix it is to add the biggest fan that will fit on the condenser, the added airflow makes the system work like it's cooler outside, more stable and delivering lower vent temps. Every R134 80 in our climate that has had the fan added has responded positively.

It's also critical that all of the foam and rubber seals are in place in our climate. The radiator needs to be sealed to the core support, the core support to the hood to make the air that the main fan moves come through the radiator and condenser.

You think the black maters?

Bring your black beauty up here and park it next to my white junk in the sun at noon. After an hour of so we can measure the temps, I'm betting black is good for +10F, cant be good for a system that we already push very close to the limit?

 

[-Spike-]

I'm betting black is good for +10F, cant be good for a system that we already push very close to the limit?

I'm in for a ten spot at +15*F. Shall we make it a pool? Make it 2 hours in the sun, and measure the driver's headrest surface temp.

-Spike (Black is brutal)

 

[RavenTai]

my 80 is black, its hood is the best place on the property to dry things,

 

[greauxpete]

I have a themometer in my center vent....when I leave at 5PM it registers 140F....

 

[Gieser]

I keep a pair of these in my console because the steering wheel is just toasty at 135 degrees

 

[Pskhaat]

Well, finally reading this thread and i do believe my 80 suffers (or did suffer) the same periodically forever. I'm gonna get me one of them fancy new switches now.