2nd Gen Non-Engine/Transmission AC issues in Texas!!

[Texis]

I am having AC compressor clutch issues. The clutch cycles non-stop ever 5-7 seconds. 5 seconds on..... 5 seconds off... ... 5 seconds on, etc. This is on the recirc setting, which should not cycle the clutch at all. The bottom line is the truck ain't nowhere near cooling and it's freakin August in Texas.



I have replaced the clutch a couple of times in the past 8 years and the low freon sensor once, 2 years back. The clutch or compressor do not act like either is the problem, the air is plenty cold when it's engaged and it engages correctly... with a small "click"... then instant COLD.



If the freon were low, or if the compressor were dying, I can't see that it would be this cold when the compressor engages??



Currently I am thinking that the low freon sensor is screwed up again. I ordered a new one today ($28 bucks). Hopefully that will fix it? I have not checked the freon levels, as it blows very cold (when the clutch engages)



Anyone have any inputs? ideas, etc?

 

[BIGNASTY]

How about issues just in Texas been so hot there its a wonder that spontaneous combustion isnt a problem

 

[fest3er]

Most likely, the rapid cycling could be low R134. When the compressor clicks on, it rapidly sucks the low side down to about 23 PSI; at that point, the low switch opens and disengages the A/C clutch. When the low side pressure rises to about 45 PSI, the switch closes, engaging the clutch.

Less likely, the problem could be due to the PCM. Remember that the PCM is also in that circuit and can disengage the clutch when it wants. (Mine failed completely years back; the shop rewired it and took the PCM out of the circuit; a diesel has so much torque, there's no need for the PCM to disable the A/C. )

Least likely, the high pressure side is getting too high and opening the clutch power circuit.

It's also possible that the evap (heat exchanger in the dash) is clogged with guck. But you say it's instantly cold when the compressor is engaged, so this is really unlikely.

You can clean the low-side switch with a good solvent; just be sure it's all evaporated before you reinstall it (leave it in the sun for a few hours). Use a cheap parts-store gauge to watch the low-side pressure. If it stays within the 25-43 PSI range when you jumper the low-pressure connector, it points to the PCM and/or high-pressure switch. You can jumper B+ to the clutch side of the disconnected low-pressure switch. If it starts behaving properly, the PCM is at fault.

Don't mess with the high pressure switch. If you bypass it too long, it'll make a hellacious noise and you may need to change your trousers.

 

[JLandry]

Could the high side switch possibly be faulty?



John L.

 

[SHobbs]

How about issues just in Texas been so hot there its a wonder that spontaneous combustion isnt a problem

I am waiting for that to happen. Been almost forty two days in a row above one hundred and at my place I have not seen rain in two months.

 

[LRutigliano]

I am having AC compressor clutch issues. The clutch cycles non-stop ever 5-7 seconds. 5 seconds on..... 5 seconds off... ... 5 seconds on, etc. This is on the recirc setting, which should not cycle the clutch at all. The bottom line is the truck ain't nowhere near cooling and it's freakin August in Texas.



I have replaced the clutch a couple of times in the past 8 years and the low freon sensor once, 2 years back. The clutch or compressor do not act like either is the problem, the air is plenty cold when it's engaged and it engages correctly... with a small "click"... then instant COLD.



If the freon were low, or if the compressor were dying, I can't see that it would be this cold when the compressor engages??



Currently I am thinking that the low freon sensor is screwed up again. I ordered a new one today ($28 bucks). Hopefully that will fix it? I have not checked the freon levels, as it blows very cold (when the clutch engages)



Anyone have any inputs? ideas, etc?

Recirc setting closes outside air. The air inside the cab will get dehumidfied and cooled pretty quickly and it WILL cycle the clutch.



Try going to Outside air (recirc LED off) and turn your blower to speed 3. It should stop cycling due to the load across the evap.

 

[WDixon27]

my vote is low freon, short cycling is a classic sign with a accumulator system, jump the low pressure switch and it should stay on, if it does acquire a 12oz can of r134 and tap then install (don't leave switch jumped, can burn up compressor if low on freon, no freon no oil circulation) a can should be enough to get it up to snuff. if it gets cold enough in the cab the clutch can cycle but not in triple digit heat and not that fast, 5 on and 5 off is almost certainly low freon

 

[Texis]

Thanks guys, low freon is the issue i fear the most! It could mean that the evaporator has a leak (deep in the dash!) I would rather be replacing a compressor than the evporator. But I suppose when they get this old the leak could be anywhere?



I replaced the evaporator when I bought the truck back in 02. Used a freon sniffer at the ducts to locate the problem. It has been slowly getting worse over the last couple of months, and only now is it unbearabe.



I will add a can of R134 and hope it last the summer..... and put a spare can in the tool box! Ah the pleasures of old trucks!

 

[HHhuntitall]

Thanks guys, low freon is the issue i fear the most! It could mean that the evaporator has a leak (deep in the dash!) I would rather be replacing a compressor than the evporator. But I suppose when they get this old the leak could be anywhere?



I replaced the evaporator when I bought the truck back in 02. Used a freon sniffer at the ducts to locate the problem. It has been slowly getting worse over the last couple of months, and only now is it unbearabe.

Probably low freon, as fest3er explained. I see it all the time, and top off the system and fix it. My wife's 97 has to have it done every 3 years, as well as two of my other customers. The leak could be anywhere, yes. Most likely not the evaporator, as it's the newest. Most common is the front compressor seal... . look for oil around the clutch assembly.

I will add a can of R134 and hope it last the summer..... and put a spare can in the tool box! Ah the pleasures of old trucks!

What else you have to do that you like so much?!?

How about issues just in Texas been so hot there its a wonder that spontaneous combustion isnt a problem

Not funny! Lost couple thousand acres in Kent County in April, hasn't rained since November last year in places. West Texas Fire Update: Kent County Blaze Prompts Evacuations - BigCountryHomePage The picture in the article was taken from the road due North of my headquarters ranch house and barns about 1/2 mile. We evacuated Rotan that night, and the fire was tracking at 24mph at one point!! Overall, there was 190,000ac burned. I lost 7. 5 miles of exterior fence alone!!



I helped some friends plant 4900 acres of cotton in Haskell and Jones Counties, and it ALL insured out. Not a single seed came up. At my place in Denton County, I got one hay cutting on my grass and sudan, and it's just shriveled up, now. Even my native grass is starting to go dormant it's so hot and dry. I've lived in this barn for 10 years this year, and this is the first year I've had to water around the foundation. This sucks!!

 

[Bill Stockard]

I've lived in this barn for 10 years this year, and this is the first year I've had to water around the foundation. This sucks!!

Were you around north Texas during the summer of 1980? This summer is a repeat performance.



Bill

 

[HHhuntitall]

Were you around north Texas during the summer of 1980? This summer is a repeat performance.



Bill

Yep. Still just a kid, but I remember Dad running a dozer and cleaning tanks out, while I killed snakes with a hoe... . I also remember a big tank we dug filling up in two days when it finally started raining!!! I could use some of that this week!! I've got a lot better grass this year than in '80... . I don't remember being so stressed back then.....

 

[Texis]

1 can of r134 did the trick. Clutch is no longer cycling, inside the cab is cold as a freezer. NOW... how long will it last, dunno?



Thanks guys.

 

[BIGNASTY]

I am waiting for that to happen. Been almost forty two days in a row above one hundred and at my place I have not seen rain in two months.

So do a rain dance, the outcome of a rain dance is all in the timing