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Discussion Starter #1
Basic problem: NO A/C, compressor clutch is not engaging.

So I have read tons of posts and this is what I have tried so far. I tested the power at the AC compressor and got nothing. Then I went to the connector on top of the canister and put a jumper on that and still no power at the compressor. I also checked every fuse on the car (under hood & under dash) and they were all good. I dont know much about this vacuum tube people talk about or if it would have anything to do with preventing power to the compressor. If anyone can help me further diagnose this problem, I would appreciate it. Thanks in advance.

Burt

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94 GT convertible 5spd
 

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Discussion Starter #3
ok, correct me if I am wrong, but I thought that the sensor that I bypassed with the jumper was the sensor that measures the pressure or level of refrigerant.

Burt
 

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Discussion Starter #4
I think it may be the WOT switch. Now, the problem is, What does it look like, and where exactly is it. Also, is there a way to test it?

Thanks, Burt
 

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Ok the first test would be, with the engine running, when you set the dash switch to turn on the A/C does your radiator cooling fan run, If the fan runs then the EEC's WOT switch is OK ( the WOT switch is just a relay in the EEC that disables the A/C compressor above 70% throttle). Its a common mistake so don't be offended, some people mistakenly put the jumper for the low pressure switch in the switch instead of the connector with the wires in it, if you put the jumper in the connector with the engine running and the compressor clutch does'nt engage within 30 seconds then you have a blown fusible link, broken wire or connector.

Have a good one
Jim
 

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burtcampbell said:
Basic problem: NO A/C, compressor clutch is not engaging.

So I have read tons of posts and this is what I have tried so far. I tested the power at the AC compressor and got nothing. Then I went to the connector on top of the canister and put a jumper on that and still no power at the compressor. I also checked every fuse on the car (under hood & under dash) and they were all good. I dont know much about this vacuum tube people talk about or if it would have anything to do with preventing power to the compressor. If anyone can help me further diagnose this problem, I would appreciate it. Thanks in advance.

Burt

________________
94 GT convertible 5spd
You could also try your cycling switch. Its like $30 from Ford and takes 2 seconds to replace. Its on your passenger side of the firewall. My probs were similar to yours and this cleared it up
 

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Discussion Starter #7
OK, I definitely did the jumper correctly. and the fan does come on when I turn the A/C on. I am not sure I understand how that rules out the WOT thought because I dont see how the WOT would do anything with the fan other than possible turn it on. But I am willing to let that go if you are sure. You say that I may have a blown fusible link. What do you mean, or where is it and how so I test the fusible link. Also, 95CobraofDeath says it may be the cycling switch. Is there a way to test that also. I dont know where either of them are, so if anyone knows please assume I don't. Thanks.
 

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burtcampbell said:
OK, I definitely did the jumper correctly. and the fan does come on when I turn the A/C on. I am not sure I understand how that rules out the WOT thought because I dont see how the WOT would do anything with the fan other than possible turn it on. But I am willing to let that go if you are sure. You say that I may have a blown fusible link. What do you mean, or where is it and how so I test the fusible link. Also, 95CobraofDeath says it may be the cycling switch. Is there a way to test that also. I dont know where either of them are, so if anyone knows please assume I don't. Thanks.
I dont know how you would test it...someone shot that suggestion at me and i replaced it because its not really expensive and its very easy to replace. Its hard to explain where it is..it looks kinda like a fuel injector with a tan plastic cover. There is a tube where your AC lines run into against your firewall on the passenger side. It sits on the top and has a few wires coming out of it. Sorry the description is not very descriptive, if you have a chilton or haynes manual it points it out. Im almost sure this is your problem. Plus it sounds like an easier solution than chasing down blown fuse links;)
 

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Discussion Starter #9
Pics attached

See the pic. Can anyone tell me if I captured a picture of this "cycling switch" If not, which way do I move the camera? Also, I pointed out where the I put the jumper.




Thanks
 

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Re: Pics attached

burtcampbell said:
See the pic. Can anyone tell me if I captured a picture of this "cycling switch" If not, which way do I move the camera? Also, I pointed out where the I put the jumper.




Thanks

haha thats the cycling switch...the one I bought from Ford is tan instead of black..guess i should have said that:D
 

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Discussion Starter #11
Well, it looks like I will fry tomorrow. I am still trying to figure out why there is no power making it to the compressor. I have already ruled out the pressure switch, low freon, maybe the WOT switch(I still need better proof). All that is left that I know of is a fuse (I checked both locations) or a bad connection. Is there something that I am missing?

Burt
 

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:confused: :confused: :confused: :barf:
This is my last attempt to revive this thread. I seemed to have reached the point that nobody knows what to do next. Basically I know its not the freon, pressure sensor, compressor, probably not the WOT. If you read the al the posts, you will get a better idea of what I have done and checked. If nobody else can help me I am stuck and will be bringing it to the shop tomorrow morning. When I get there I will grab my ankles and hope for the best. :eek: I will post back and let people know what was wrong so that when this happens to the next guy, maybe he will come accross my thread and save a few bucks.

Thanks guys (especially those that tried to help).
Burt Campbell
 

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Ok, another thing that can be wrong.. is the ccrm module.. this is located on the passenger side of the radiator.. it is a black box witha bunch of wires going to it.. Constant control relay module.. ON 94 and newer mustangs this box controls the following items (like a individual relay would but this acts as a bunch of relays) :: a/c compressor,, cooling fan,, eec power,,, fuel pump power,,,, etc etc.. If this box is bad it can cause the compressor NOT to come on... the low pressure/ clutch cycling swith you jumpered should have eliminated a low refrigerant charge.. There is also a HIGH PRESSURE cut out on the passenger side near the front by the a/c condensor.. It (i believe ) is supposed to shut compressor down in the advent of the head pressure getting too high.. it could have malfunctioned? (i dont have a wiring schematic handy here at my house.. but if you want you can call me at 936-876-3121 during normal business hours and i will get my wiring book and try to help you trace the circuit..
 

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Discussion Starter #14
Tony,
Thanks so much for the reply. Below should be the wiring diagram that I have for this part of the electrical. It is from the Chiltons manual. If this helps, please let me know. I unpluged what I think was the high pressure switch, and there were 4 connectors inside so I didn't want to mess with jumping it. What I did notice though is that when it is unplugged and I start the car and turn the AC on, the fan does not come on. Then when I plug it in, the fan comes on. That tells me that the switch either works, or at least partially works. I found the CCRM and actually pulled it out to look at it. If you or anyone can help me test this further, I have an order of Omaha Steaks coming your way. (only the first person to accurately help me diagnose this problem gets it though) Thanks, Burt

 

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Hey,

I will look at my book at shop tomorrow.. I know this does not help you today but the schematic you put comes up so big i can't trace the circuit as easily.. plus it is better than nothing but not nearly as good as the ford book i have at shop.. (put out by ford)

I will try to get you a step by step on how to diagnose exactly where your problem is.. My best bet is going to be the ccrm module though.. Do yourself a favor if it is get one from FORD only .. Have put lots of them on taurus/sables and i once put 4 aftermarket ones on and after pulling my hair for a while went and got a ford one and NO more problem.

Tony

PS>.IF you want to call me at shop tomorrow i will try to guide you thru it on the phone.. 936-876-3121
 

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Ok,

If you still need help let me know i have my book wiring schematic book at home.. Looking at the schematic get a test light and see if with the a/c in the on position you have power at the low pressure switch ( with it unplugged it will only have power on one side of the plug) (the one that screws onto the accumulator next to the firewall on the passenger side) Make sure the engine is running .. ASSUMING it has not gotten a leak and all the freon has leaked out you should then have power on the other side of the switch when you plug it back in.. IF NOT then you either have a leak that leaked all your freon out OR you have a bad low pressure/clutch cycling switch.. IF you have power there then go to the pressure swith with 4 wires on it.. that screws into the a/c line by the radiator on the passenger side.. Unplug it with the a/c still in on position and car running.. (make sure you plugged the low pressure switch back in)... There should be four wires.. one should be dark blue with a yellow stripe /tracer on it.. see if it has power... IF it does then plug switch back in and see if the dark green /orange wire has power on it(you will have to either skin the wire a little or pierce it with your test light ... IF YOU HAVE POWER AT THESE PLACES then you either have a bad ccrm module OR a bad compressor clutch .... To test the compressor clutch unplug the compressor and see if you have power on the black/yellow tracer wire in the two wire compressor plug... IF you have NO power and you have tested thru the circuit like i have explained then your ccrm module is bad... IF you have power at the compressor clutch then either the compressor clutch is bad OR you do not have a good ground.. (the other wire on the plug). In which case i can lead you thru testing the ground if necessary... All in all the most likely culprit is the ccrm module... But i like to go by the words of my Dad (electrician for 40 plus years) TEST ,,DON"T GUESS!!

Hope this helps you and that i have explained the trouble shooting procedure in a way you can understand it...

LEt me know if you figure it out...

BigT
 

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Discussion Starter #17
Big T,
Thanks for the very detailed description. I had already tested it as much as I could and was 99% sure it was the CCRM. I needed to bring it in to my mechanic for something else anyways so I just let him verify I was correct and replace it. He was very fair only charging me $115 for the ccrm and 1 hour labor. (even though it was a 10 minute job considering I told him what to test.) Thanks anyways, I am sure that there will be many more just like me that will find this thread very healpfull. That's what this forum is all about.


Burt
 

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I know this an old thread but wow am I thankfull I read this! I was going to spend hundreds of dollars and replace the compressor! Thanks guys!

- R
 
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