1989 gmc a/c - Page 2

silverhairdeere · 08-12-2009, 09:35 AM

and the winer is ? , went out today by-passed the low presser switch with a wire , it was so cold in the cab , i thought about gloves , the compressor ran smooth , no hint of anything , no squeal , no engine bog , no nothing , sooooo do you think it is still low on freon or is it the switch .

shd

bradrhale · 08-12-2009, 09:41 AM

without a pressure test, there is no telling. bypassing the switch just tells the clutch to stay in, whether it is low or not. it might be just the switch, but i would pressure test it. if you go and change the switch, it will still act up if it is low. then you spent money on a part that you didnt need. anyone around you own a set of manifold gauges??

silverhairdeere · 08-12-2009, 09:43 AM

Quote:

Originally Posted by bradrhale

without a pressure test, there is no telling. bypassing the switch just tells the clutch to stay in, whether it is low or not. it might be just the switch, but i would pressure test it. if you go and change the switch, it will still act up if it is low. then you spent money on a part that you didnt need. anyone around you own a set of manifold gauges??

nope , befor the switch i will try another can of freon . i never use stop leak or turn the can upside down when putting the stuff in .

shd

bradrhale · 08-12-2009, 09:46 AM

dont put another can in there unless it needs it. it is very possible to overcharge the system. i guess you can buy a can with a gauge on there and get the same effect. without knowing for a fact that your freon is low, i cant tell you exactly what to do because i dont want to suggest something that is going to ruin your system. find out what the pressure is and that will tell you whether it is the switch or the freon level.

BernieB · 08-12-2009, 09:50 AM

Quote:

Originally Posted by bradrhale

probably because someone took that one out. everyone that i have seen had a schrader valve in it. why someone would pull it out and leave it out is beyond me.

Well, I was replacing the factory accumulator with a brand new one. I just went and checked to see if the original was still in the scrap pile but it's already been recycled.

And getting back to the matter at hand...

Without pressure readings it's impossible to pinpoint the problem. As others have said, bypassing the switch just keeps the compressor clutch engaged. If your system is low you can damage the compressor that way. And... even if the system is properly charged, bypassing the switch does not isolate it as the problem. The switch could be working fine but you could have a bad plug. Or any one of another dozen reasons. The only way to tell for sure is with proper diagnosis, complete with proper pressure readings.

silverhairdeere · 08-12-2009, 09:50 AM

Quote:

Originally Posted by silverhairdeere

my ac compressor clicks off and on every 5-10 sec yet it is cold , it was changed over by po to 134a with new everthing . the gage shows about 22 (filled)but the gage flooders when the compressor clicks off and on . soooooooooo what now

shd

at 22 it showes the lower end of filled on my gauge , it is a quality single line with all brass ends not the cheap plastic one .

shd

bradrhale · 08-12-2009, 09:55 AM

22 pounds is low. i would be willing to bet money on that. might go ahead and fill it up to good and if that still doesnt work, change out the pressure switch. if that cures it, then we will know that you were just a tad low.

leolkfrm · 08-12-2009, 01:00 PM

make sure you have a good connection at the switch, gently move it and hold in various positions and see if the clutch stays engaged

silverhairdeere · 08-12-2009, 01:38 PM

Quote:

Originally Posted by silverhairdeere

and the winer is ? , went out today by-passed the low presser switch with a wire , it was so cold in the cab , i thought about gloves , the compressor ran smooth , no hint of anything , no squeal , no engine bog , no nothing , sooooo do you think it is still low on freon or is it the switch .

shd

i did all wires are tight , made no difference , i just can't understand if it wasn't the switch , then it wouldn't have been so cold , and if it were that low , why did it come on and was so cold , compressor didn't bog or didn't make bad sounds and motor purred like a kitten .

shd

bradrhale · 08-12-2009, 01:49 PM

low freon will still cool if there is a little there. i can wire around a system that reads 5 on the low side and get cold air. problem is that when you leave it run like that, it will ice over the evap coils and prolonged use will cause damage to the compressor. the compressor, when low, will not make any unusual sounds or bog down the motor. it will throw a belt before that happens and if it were to bog down, that would mean your compressor is locking up, which is not your case if you said it cooled.

08-12-2009, 01:00 PM	#18
leolkfrm Senior Member Join Date: Mar 2008 Location: N.Y. Posts: 4,932	make sure you have a good connection at the switch, gently move it and hold in various positions and see if the clutch stays engaged __________________ 4 wheels move the body 2 wheels move the soul B.W.A.I

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
1989 gmc leaking oil help	bulachip	GMC Truck Forum	4	03-27-2008 03:28 AM
4x4 Low in 1989 K2500	Captain Morgan	Chevy Truck Forum	3	01-05-2008 06:44 PM
1989 k1500	Rich	Chevy Truck Forum	4	02-10-2007 07:44 AM
1989 GMC Sierra	J-ROCK	GMC Truck Forum	1	02-08-2007 08:59 AM
1989 350 to another vehicle	tnthirshey	Chevy Truck Forum	3	01-30-2006 03:07 PM

08-12-2009, 09:35 AM	#11
silverhairdeere Senior Member Join Date: Feb 2008 Location: land between the lakes tn Posts: 1,633	and the winer is ? , went out today by-passed the low presser switch with a wire , it was so cold in the cab , i thought about gloves , the compressor ran smooth , no hint of anything , no squeal , no engine bog , no nothing , sooooo do you think it is still low on freon or is it the switch . shd

08-12-2009, 09:41 AM	#12
bradrhale Senior Moderator Join Date: Apr 2006 Location: Texas Posts: 9,558	without a pressure test, there is no telling. bypassing the switch just tells the clutch to stay in, whether it is low or not. it might be just the switch, but i would pressure test it. if you go and change the switch, it will still act up if it is low. then you spent money on a part that you didnt need. anyone around you own a set of manifold gauges??

08-12-2009, 09:46 AM	#14
bradrhale Senior Moderator Join Date: Apr 2006 Location: Texas Posts: 9,558	dont put another can in there unless it needs it. it is very possible to overcharge the system. i guess you can buy a can with a gauge on there and get the same effect. without knowing for a fact that your freon is low, i cant tell you exactly what to do because i dont want to suggest something that is going to ruin your system. find out what the pressure is and that will tell you whether it is the switch or the freon level.

08-12-2009, 09:55 AM	#17
bradrhale Senior Moderator Join Date: Apr 2006 Location: Texas Posts: 9,558	22 pounds is low. i would be willing to bet money on that. might go ahead and fill it up to good and if that still doesnt work, change out the pressure switch. if that cures it, then we will know that you were just a tad low.

08-12-2009, 01:49 PM	#20
bradrhale Senior Moderator Join Date: Apr 2006 Location: Texas Posts: 9,558	low freon will still cool if there is a little there. i can wire around a system that reads 5 on the low side and get cold air. problem is that when you leave it run like that, it will ice over the evap coils and prolonged use will cause damage to the compressor. the compressor, when low, will not make any unusual sounds or bog down the motor. it will throw a belt before that happens and if it were to bog down, that would mean your compressor is locking up, which is not your case if you said it cooled.