Here's another thing I noticed on my vacation. I don't think the air conditioning is cycling. I mean that when I first turn it on its pretty cold, but after 15 minutes it seems warmer and I don't hear that familiar cycling you get with most air conditioners. Could something be amiss? What should I look for or test?

Brad

 

Start the truck and lt it run , you can watch the compressor to see if it cycles, if not on the firwall on the pass side is a switch which controls that,,its 20 bucks from autozone.

 

and that switch would look like what?

 

You should put a set of guages on the system to see what the pressures are doing. If the fan clutch releases and does not pull air thru the rad, the a/c gets warm and the hi press gets real hi but goes down to norm when the fan kicks on. you should direct a fan towards the rad to increase the air flow while testing. Is your system still R 12 or has it been converted? Right now I would guess that your a/c is low on refrigerent and the fan clutch is kicking out completely. Also check your condensor for being plugged up with bugs.

 

If you are still virgin,
meaning the AC is using R-12, then check the sight glass and see if it is clear, bubbles or slimey looking oil? anything much over a few ocasional bubbles would indicate a low charge.
Quickest way to check the state of charge, then go from there.
Jim

 

Yes, I'm still a virgin! R12. Thanks for the replies

 

How much success of any of you with converting over to other than R12? Sounds like a hit or miss to me?!! If all I need is a switch so it cycles then that's probably prudent for now wouldn't you say?

thanks,

brad

 

LOL you might not want to convert to 134a just yet "it causes cancer" or so they say, price has shot up to 12 or so per can. There is a r12 replacement called freeze 12, should be a less expensive version of 123a soon.

Blowndodge i'm sorry i didnt go in to more detail, i thought that was only question you needed answered, On the large line (suction) where it goes through the firewall is a switch, it kinda looks like an oil sending unit, it screws off and theres a shrader valve under it so you wont lose your freon. You can watch the compressor to see if its cycling.

One of the most common probs with automotive a/c is it works well at first, the main reason for this is your head pressure rises past 300 psi, as rpm's go up so does your head pressure, at that point it will go off on high limit switch. The main reason for this is no air flow over the condenser, whether its just dirty or fan clutch isnt working properly.

Theres also a low pressure switch which cuts off at around 20 psi, this usually indicates low freon charge. As was said earlier start the truck turn a/c on and look in the sight glass on the dryer, its the round black can on the passenger side, if you see bubbles its undercharged, unless its on 134a. The reason i exclude 134a is at proper charge it will still have bubbles.

Stick a set of gauges on it depending on the outside air temp the pressures will be in the area of 40/200, these will change as it cools off inside the cab or if its hotter or colder outside. Here is a chart to give you a better base to work with, http://www.ackits.com/index.cfm?fuseaction=Chart

 

Thank you Loch. Air conditioning ain't my gig so I'm pretty ignorant on its workings

When it cycles, what am I looking for? Thats when the switch sets off the wheel on the compressor and starts turning correct?

as always thanks,

brad

 

I have just converted my wifes volvo AC from R-12 to a product called Hot Shot (R-414B), it is a direct drop in and you do not have to replace the oil.
I have a 25# drum and a digital charging scale so charging is no problem for me.
It is charged to 80% same as the R-134A conversions are.
It is also sold in single cans.

http://www.icorinternational.com/
http://www.aircondition.com/wwwboard/current/20418.html

 

and the results Jim? Have you considered doing that to your Dodge? Since your in the Southern Cal region I may need to give you a buzz!

brad

 

Blowndodge cycling is basicly the compressor coming on and off, it does this to maintain a constant coil temperature, our trucks use exspansion valves instead of an oriface tube, where cycling is critical but not on a oriface tube. They also cycle in the winter when the defrost is on so it will take moisture out.

 

so if my cycles on and stays on, it will start to get warmer? I think that is it because I turned it on today and it never cycled off!

 

Hum im not being clear , sorry im not good at relaying info, if its getting warm and not cycling, did you look to see if theres bubbles? if there is its low, a cycling switch can go bad in open or closed position. cycling works like the thermostat in your home, when coil get to a low temp it goes off, when it warms up it cycles back on, also dont forget ppl often take off or bypass switches thinking they work better.

 

Let me see if I can explain it better.

When I first turn on the ac it blows nice and cold. With most other vehicles after a short while, you can here a change in the blower sound, just like your home ac does, it changes pitch and you can hear it cycling. Mine never changes pitch. I never hear it cycle and after about 15 minutes the air is not near as cold as it was when I first turned on the air. When I park it after driving with the air on for a half hour, the condensation that drips upder the truck is a large puddle, like a two foot circle. It almost looked like my radiator was leaking. I was just wondering if it was freezing up because it never sounds like it cycles?

make sense?

brad