A/C not blowing cold air!!!

savegoodautonfg · Jun 22, 2006

Well, i thought last time i checked it was working a few months ago but recently my heater core went and i bypass it for right now and now i just tried my a/c cuz its so hot in NY where i live right now and it only blows hot air, not getting cold at all.

What do i have to replace and how do i check. i have no idea at all about the a/c components in the car so fill me in.

HISSIN50 · Jun 22, 2006

Do you know if your AC clutch is engaging?

If not, I'd check the Low pressure switch. If you have 12 volts in but not out, put manifold gauges on and see what pressures you have (you will likely have to jump the LPS for testing).

Go from there. I'm sure the other guys will post detailed info.

Good luck.

FORCED2DV8 · Jun 22, 2006

Like hissin said it could be the low pressure switch, Which means you may have a small leak somewhere, and theres not enough presure in the line to activate the switch there for turning on the AC compressor.. by pass the switch and then see if the AC compressor runs, if it does and you still have hot air, then go buy a r 134 recharge kit and charge the system, You may have to do this once a year, since you most likley have a leak, Or you can go to a shop and they will charge you for it, If you can find the leak, which is usually a o ring then you wont have to recharge. But a little side info, if you let air into the system and it runs close to empty the chemicals have a reaction with the air, essentially turning to acid and eat the seals in the compressor and lines, then your screwed.. Hope this helps

savegoodautonfg · Jun 22, 2006

FORCED2DV8 said:
Like hissin said it could be the low pressure switch, Which means you may have a small leak somewhere, and theres not enough presure in the line to activate the switch there for turning on the AC compressor.. by pass the switch and then see if the AC compressor runs, if it does and you still have hot air, then go buy a r 134 recharge kit and charge the system, You may have to do this once a year, since you most likley have a leak, Or you can go to a shop and they will charge you for it, If you can find the leak, which is usually a o ring then you wont have to recharge. But a little side info, if you let air into the system and it runs close to empty the chemicals have a reaction with the air, essentially turning to acid and eat the seals in the compressor and lines, then your screwed.. Hope this helps

THanks for the help both of you. but here's the thing i dont know where the low pressure switch is nor do i know where the AC compressor is. i'm new with all this. also where would the o-rings be that could be leaking? how do i make sure air does'nt get into the system. please detailed help im new with all this. thanks in advance.

savegoodautonfg · Jun 22, 2006

r134a or r134

savegoodautonfg · Jun 22, 2006

Ok i've been looking at sealers by Interdynamics i've heard plenty of good things about them but my question is i don't htink i have a leak. cuz if i did would'nt i be feeling some cold air. i feel complete hot air. no cold at all. so do i even have a leak then?

Also do i have r134a or r12?

its a 1990 mustang gt 5.0

it may have been swapped to a 134a but if it was how can i tell?

Bolt on 5.0 · Jun 22, 2006

your car came equipt with r12. R12 is expensive so now you can retrofit your car to use r134. If there is a leak and the freeon is low the ac compressor will not engage.

To test turn the car on and put on the ac. Stand over the open hood for a min or two and listen to here if you hear an audible click every so foten. If so the compressor is coming on. Most likly it will not come on.

The cheapest thing to do is go to a shop, ask them to recover all your freeon and fill with dye in the system. Take the car and hopfully it will last you some time. If you have a bad leak when the a/c stops working either brink it to a shop and tell them the a/c has dye in it and to check for a leak. Also if you get a black light and some special goggles you can look for the leak yourself. Look into buying a a/c leak detector kit from harborfreight.com. your leak is probably a slow leak and you should make it through the summer with just a recharge

HISSIN50 · Jun 22, 2006

Look for a retrofit sticker and different fittings (with colorful, large caps). The fitting adapters for R12 and 134 are different to keep people from screwing up.

If you have a shop evac the system, they can pull a vacuum on it (let's you know if it has leaks).

I would really want to get some gauges on the system - some shops will check for free or just a little money if you dont have gauges. You just need to reference them to know (not guess) that the system is charged near spec.

See Jrichker's R134 article for background info and pictures (or even a conversion if desired).

LPS is on the 'cannister' on the pass firewall. The wires point straight up, IIRC.

You cannot mix R134 and R12 products - make sure a sealer is compatible with what you have. If you should decide to use a sealer, PLEASE READ ALL YOU CAN about it - some of that stuff does more harm than good.

Good luck.

PuterAmI · Jun 22, 2006

savegoodautonfg said:
it may have been swapped to a 134a but if it was how can i tell?

If it was done properly, it would have the correct fittings on the hi and low side.

It appears that you are asking how to rebuild an engine, then telling that you don't know what a spark plug is. First, I suggest that you read the below link, especially the section on the basics of the Fox A/C system. You need to understand the basics of the system before you start to work on it. Pressurized refrigerant can blind you in a split second if you do not know what you are doing.

Next, I suggest that if it sounds like it is too much for you to learn to troubleshoot (people here have already told you how), then you should take it to a shop that advertises they do A/C work.

Last, if you do want to try and troubleshoot it, I suggest that you start off with checking the wires for insulation burn at the WOT relay. This is the small rectangular relay mounted on the front of the passenger-side shock tower. If all looks good, start the engine and turn on the A/C, disconnect the LPCS and jumper the wire connector to see if the compressor turns on. If it does, this tells you the system is working electrically. It also tells you that you have an issue with either a bad LPCS or your refrigerant is low. Do not leave the compressor going like this for more than 60 seconds or you start to endanger the expensive compressor. If you do start getting cold (not cool) air, you need a new LPCS (~$37 at Ford last time I bought one). If you do not get cold air, your refrigerant is low.

If your refrigerant is low, you need to decide to stay with R12, or convert over to R134A. The link I gave lines out a procedure that I have helped a few hundred people convert with. My Mustangs are blowing 42 degrees on 93 degree ambient days. If you want to stay R12, you also have the option of studying for your M609 certification and taking it ($20) so that you can buy R12 (~$20 a pound).

Anyways, for this post, you should donate $25 to my favorite charity.

Fox R134A Conversion

fox racer · Jun 22, 2006

Im just a LITTLE confused witht that write up in the link. Did he replace anything, or jsut clean everything? What exactly needs to be replaced to be able to use the R12? As long as the stock Condenser and evap canister can be re used Ill be happy.

HISSIN50 · Jun 22, 2006

Joe, nothing needs to be replaced to use R12. If you want to convert to R134, then you should do some swapping to avoid BD.

I believe Puter authored the article, so it wouldnt be 'he' but 'you' when asking about it.

I have great respect for many folks (Puter, I keep wanting to call you Larry - is that right? No need to answer if you're a private-type) and how they do things (albeit a little differently). Jrichker also has a great write up on converting to R134 - I'd read both articles.

Good luck to all.

fox racer · Jun 22, 2006

Thanks HISSIN... I meant converting to R134. I guess R12 is what came stock? The reason I ask what is needed is because Im starting to take apart and paint the engine bay and while Im knee deep in that stuff I want to do the conversion. Any links to Jrichker's conversion? I want to do everything the right way (like always )

dragnazz5.0 · Jun 22, 2006

if youre taking everything out than its a good time to convert it and put new seals in it anyways. replace the receiver/drier when you put it all back together since it has a dessicant bag in it that pulls moisture from the system and when you open the system it will ruin the bag.

to the original poster. start the car, pop the hood, turn the ac on. open the hood and look directly above your powersteering pump. you should see the ac compressor. if its not there than thats why its blowing hot air. but anyways, you should see it cycle on and off. it will look like it stops spinning and than starts spinning. if you dont ever see it start to spin than its a low pressure/cycling switch problem, or a wiring problem somewhere else. your best bet is to take it to a shop if you know nothing about a/c systems.

for puterami...its the e609 certification, not being an ass...but i just took it today. thats what it had on the answer sheet at any rate. epa 609 certification...either way. super easy

dragnazz5.0 · Jun 22, 2006

double post...im a noob

PuterAmI · Jun 23, 2006

Joe, I'm sorry it is not clear. Please note the part numbers of the parts I replace. I replace all *except* condenser, compressor, and evaporator. For links to jrichker's writeup, the Search button will bring up lots of posts.

HISSIN50, thank you. Very kind words. There are MANY hours in the work. My name is Ralph. I do have a brother named Larry (and Darryl, and my other brother Darryl - j/k).

dragnazz5.0 - Nope, I'm always good with someone correctin' me. Congrats on gettin' it!
And I'm lovin' this part...
"you should see the ac compressor. if its not there than thats why its blowing hot air."
That just made me laugh.

Link to testing for EPA Section 609...
http://www.epatest.com/

fox racer · Jun 23, 2006

PuterAmI said:
Joe, I'm sorry it is not clear. Please note the part numbers of the parts I replace. I replace all *except* condenser, compressor, and evaporator. For links to jrichker's writeup, the Search button will bring up lots

Thanks alot! I just reread it and got that lol. Very good write up I was just out of it I guess. Good work, also where did you go that you used those PN's? a Ford dealer?

PuterAmI · Jun 23, 2006

fox racer said:
Good work, also where did you go that you used those PN's? a Ford dealer?

Thank you!
In the document I mention where I got my parts from Torrie McPhail. Reminds me, he had to change the name of his website.

FastPartsNetwork

savegoodautonfg · Jun 26, 2006

Well, i bougth the recharge kit and im in the middle of doing it and the guage is in the blue which means it should be full and my a/c compressor clicked and then turned on and turned off and back on. is it suppose to stay running or what?

THen i went back outside and tried it again and the a/c compressor did'nt turn on at all.

savegoodautonfg · Jun 26, 2006

bump help please

jrichker · Jun 26, 2006

Hopefully you had the system vacuumed out prior to attempting a recharge. If you didn't you will not get the full refrigerant charge in without exceeding the high side pressure limit.

Try jumpering the low pressure cutout switch on the accumulator.

See the link in my sig for R134 converion help.

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