AC cycling switch

[mcrowe3797]

I just got the new ac cycling switch for R134a....
So i let the ac cycle for 2-3 minutes. It was low every 3-5 seconds it would cycle. So i added more. Once it was steady at about 40psi it shuts the compressor off and doest come back on. Could it be because i messed with the screw on the switch? What would the stock setting be set at? 90 mtx sho. It cant be the clutch since it cycles on when it was low? What should the PSI be on the lowside while running?

I put the old switch on and it wont come on unless i let it sit for a while?

Does anyone have any suggestions?

 

[Airborne]

To diagnose your AC cycling time you need to connect a gauge set to the low and high side. That will enable you to tell if you have the correct amount of refrigarant which is the most important thing and then you can diagnose your cycle time based on ambiant temperature.

 

[Shovert]

Agree. Flea markets, and Harbo Freight have cheap one's. Maurice

 

[mcrowe3797]

To diagnose your AC cycling time you need to connect a gauge set to the low and high side. That will enable you to tell if you have the correct amount of refrigarant which is the most important thing and then you can diagnose your cycle time based on ambiant temperature.

OK i will try that tomorrow. What should the high and low sides be reading?

 

[Airborne]

The high side pressure reading is also dependant on ambient temerature. Sorry, I only have a Ford manual for the '89 and '91and I don't want to give you wrong info. Hopefully someone with a gen 3 will chime in.

 

[mcrowe3797]

The high side pressure reading is also dependant on ambient temerature. Sorry, I only have a Ford manual for the '89 and '91and I don't want to give you wrong info. Hopefully someone with a gen 3 will chime in.

LOL i have a 90, you can help

 

[Airborne]

At 80 degrees ambient, high side should be about 195 psi plus or minus 25 psi. low side should cycle between 24 and 45 psi. My Ford manual states "in many instances, the clutch will not cycle off when temperatures are above 90 degrees F."

 

[rubydist]

the low side switch should open at around 25-28 psi.

if the a/c clutch gap is on the bubble of being too wide, it will often work fine when the engine is cold, but as the engine warms up, it will not engage - so do not discount the clutch as not being the problem.

with the a/c on "max a/c", the fan on high, and the ambient over 85 or 90 degrees, the clutch should not cycle off.

 

[mcrowe3797]

On the AC cycle switch, it is adjustable. I adjusted the screw. Don't ask y lol. What should it be set to? Just turn it all the way in?

 

[gmail]

i have to refill mine soon. if i get the chance and you still havent got it ill check it... but mine was seeing 25 degrees when i used my infered gauge last time i used it... loved it

 

[Mike Gallion]

Like you said, it is an adjustable switch. Factory adjusted to close on decreasing pressure to engage the clutch. prolly shouldn't have adjusted the screw but too late for that....lol

FWIW I think it will be cheaper/faster to just swallow some pride and go out and buy a new switch unless you have a means of recalibrating the switch.

 

[Racer X]

Like you said, it is an adjustable switch. Factory adjusted to close on decreasing pressure to engage the clutch. prolly shouldn't have adjusted the screw but too late for that....lol

FWIW I think it will be cheaper/faster to just swallow some pride and go out and buy a new switch unless you have a means of recalibrating the switch.

This.

 

[rubydist]

Like you said, it is an adjustable switch. Factory adjusted to close on decreasing pressure to engage the clutch. prolly shouldn't have adjusted the screw but too late for that....lol

FWIW I think it will be cheaper/faster to just swallow some pride and go out and buy a new switch unless you have a means of recalibrating the switch.

Actually, it opens when the pressure falls to the 25-28 psi range to disengage the a/c clutch.

 

[Mike Gallion]

Actually, it opens when the pressure falls to the 25-28 psi range to disengage the a/c clutch.

Once again, I humbly stand corrected....

 

[mcrowe3797]

Well last night i was messing with it again.....

the car was sitting for a few hours and when i started it the ac came on right away after it warmed up it would not reengage. I tried jumping the cycle switch connector and still no luck. I am thinking RUBYDIST is right with the ac clutch gap. It was about 80-82 degrees at the time.

What should the gap be set at? How do i adjust that lol?

Anyone that can help me get this fixed I can sandblast almost anything you need, just pay for the media, shipping and a 6 pack lol

 

[Mike Gallion]

According to 94 shop manual air gap specs are 0.021-0.036 inch.
Here is a link with diagrams and some removal tips:
http://www.shoforum.com/showthread.php?t=112345&highlight=clutch+gap
I have a photo floating around here somewhere comparing a worn out clutch to a new one. If I can only find it......

 

[mcrowe3797]

According to 94 shop manual air gap specs are 0.021-0.036 inch.
Here is a link with diagrams and some removal tips:
http://www.shoforum.com/showthread.php?t=112345&highlight=clutch+gap
I have a photo floating around here somewhere comparing a worn out clutch to a new one. If I can only find it......

That helps a crap ton! Thanks

Need anything sandblasted, computer or phone modding done? lol

 

[Mike Gallion]

Found them.... there are a couple on my Photobucket page.
http://s1049.photobucket.com/albums/s396/coolmeiser/?action=view&current=oldvsnew.jpg
http://s1049.photobucket.com/albums...r/?action=view&current=Oldclutchwithshims.jpg

 

[mcrowe3797]

Found them.... there are a couple on my Flickr page.

http://www.flickr.com/photos/29459545@N03/7733222732/in/photostream

need a flicker account to view

 

[Slo-Sho]

When you suspect that the compressor is acting up again, take the end of a broom handle and strike the front of the clutch. If it engages, you found your problem. I personally had to remove one of the shims on my compressor to make it work again.