A friend of mine has a dodge ram truck and his a/c is not working. Just warm/hot air comes out. I looked under the hood and see that the compressor activates for about a second and then shuts off for about 5 seconds. On and off just like that. I put a similar relay for the a/c clutch relay but that didn't change anything. Is this a low freon thing or something else? Also the lines going into and out of the compressor are warm/hot. No difference in temp between them. Any help would be appreciated. If it's a compressor then I would replace it with a junkyard compressor and get a refill, but first evacuating what's left of the freon in the system by a pro. If it's just low, then I'll get a pro to do the refill. I suspect that if the freon was low, there should be SOME cold air? Thanks in advance.
Regards,
Steve

hiperf402

if you don't have access to gauge then take it to someone who does. without gauge readings, it is hard to tell you what might be the problem. most likely it is low on freon, but even then you should charge it to gauge readings.

hvacservicetech_07

It's low on freon, What year is the truck? If it's new enough then most likely it uses 134A which can be baught at walmart along with the gauge and fill hose pretty cheap, very easy to do. This may only be a short term fix, if it's low on freon then obviously it has a leak and it would be cheaper just to take it to a shop and have it repaired.

brandy681

You could be low on freon or you may have a bad compressor or a leak in the line. The cheapest thing that you can do is add a small amount of freon like 25lbs and this will not be very cool but just a little and if it works than add 25lbs more and it should be very cool. It is possible that you have a leak and it will leak out and waist the freon and you will be losing money. What year is his truck??? If it is a fairly new truck, you most likely have no freon or a small leak but an older truck you can bet needs a new compressor. Take the truck to a TRUSTED mechanic and see if someone will inspect it for free and then if it is not the compressor or a leak, just add freon!!

stevanrk

thanks for the input so far. A new piece of info is that he recalls someone telling him that the evap core was bad and was going to be expensive because of it's location behind the dashboard or something like that. Could that be a problem or are we still looking at a low freon situation. No I don't have any guages, but I saw some for cheap at NAPA (15$). Would the comp cycle on and off because of an evap problem? It's a late 1990s truck I for got to ask which year exactly. Thanks again for all the help.
Regards,
Steve

hvacservicetech_07

I would say that the Evap. coil is leaking, this is very common in dodge trucks, They are kinda hard to replace, I changed one in a friend of mines truck, but it can be done. I would say the truck uses 134A which can be baught at walmart along with the gauge, it's very simple to charge it. Try adding freon to it, but I'm sure this will be a temp. fix.

brandy681

I work at a mechanic shop, I don't work on cars there but my dad owns the business so I work there. When my car had this problem my dad added freon and as soon as I turned on the ac I heard a noise for about 3 minutes and it was still blowing out hot air. This is when I was told for sure that I had a bad compressor. Yea it waisted a little money but It is easier to check this way and didn't cost too much for my dad!! The coil and lines are easy to check, this should be done first and then if you have no leakes then all you need to do is add freon if you have no leakes, IF your truck is fairly new then it should not have a bad compressor and your problem will be solved. On the other hand a compressor is harder to tell if it is bad or not, untill you add the freon to know for sure! To answer your question about it being cool if there is no freon in it, no, if there is little or no freon in you compressor than it will blow out HOT air! If it is just a little bit low on freon than your air will blow out midly cool but not good at all!


As for getting a compressor at a junk yard, high chances are that the compressor there will be bad also or will go bad shortly there after.. It would be best to buy a new one because it will last a LOT longer and you will save money in the long run. I am not sure your year of truck that you own but a compressor will cost about $300 not installed. I have had to go through about 5 compressors in all of the cars that I have owned but in our shop we have had a lot of people with coil leaks also, this happens more so that having a bad compressor because a compressor will usually last 8-12 years depending on how much you use the air. Allthough I have seen some that go bad in only 5 years time! Right now you are not sure if this is what you need but I am sure that you can have a mechanic that will look at it for you for free, not all will look at it for free but I am sure someone will take a look at it for you and give you a quick answer because it shouldn't be that hard after looking at it to tell EXACTLY what the problem is! Let us know if you find out!!

hvacservicetech_07

Brandy, you are basicly very much full of SH*T, thanks for the bad rating, like I care. The guy is here looking for info so that he can fix this problem himself, you just typed two paragraphs of nothing.................

hvacservicetech_07

Once again, I'm sure you are just low on freon, if after charging it you want to find the leak your self, most auto part stores sell a leak detector kit that comes with dye that you run through the system and a black light that will detect the dye.

brandy681

I have allready told him to do that, duh!! What other choices does he have?