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Okay so i had my local H/S Recharge my trucks a/c, the shop teacher is knowledgeable and has done many before, they have all the equipment to do it etc. Anyway he says to me yesterday, ok David we are all done, there was a little left in the lines, we checked for leaks and found none, we evacuated all the old refrigerant and replaced it with new stuff. I'm like yup ok.. and he's like we did the temperature test and the vents were blowing air at 40.8 degrees F. So i'm like yea thats good. Well right when i got in it i noticed the air wasn't cold at all. I thought i'd try again today, and still the same thing the air isn't cold at all, so i looked under the hood and noticed the cluthc isn't engaging. I took it back to him and he said yup it's not engaging, he messed with a wire or two but then finally said bring it in tommorow and i'll look at it. I'm thinking it's a wire, or relay. The fuses are all good we checked them, but how do i go about checking a relay? Could a relay cause the clutch not to engage. What do you guys think?

Thanks
-David

I don't see why not. As long as it isn't mechanical, it's usually electrical.

the relay is what electrically switches the clutch on and off. If the relay is dead, that would certainly be a problem.

you can test a relay with a 12V power supply if you know which leads do what.

yea i figured you could test them and i figured they certainly could go bad, but i don't really know which relay it is, and our dodge dealer is incredibly stupid, i know much more than him, he can't give me info on ANYTHING.. I'll wait and see what the shop teacher says tommorow.
thanks

Maybe you do have a leak? The clutch won't kick on if the system is too low... Buy a book, you should have one anyways... I'd check and make sure that it's not low, if it isnt jump the wires and engage the clutch manually (like you sometimes have to do when your filling it.) If it comes on that way its probably the relay... You should be able to take the relay to almost any parts store and have them test it...

EDIT: Make sure they put oil in the system...

If the clutch has brushes, that could be a problem as well.

Now recently it started this thing where it blows the fuse. It's a 20 amp fuse, shared with the horn only. If the A.c is pluged in at all, specificaly turned on it will blow the fuse ( keep in mind that the clutch still hasn't engaged). I've looked over the wiring the best i know how ( i know almost nothing about A/c's). Does anyone have any idea as to the cause of this problem, or the fix?

I have tried manulay jumping it and no such luck, so im ruling out the low pressure switch,etc..

I read on another forum that this may be caused by coils going bad or somethign of that nature? I find it rather odd that this all started happening after the shop teacher "Serviced" it.. I'll tell you what if it isn't fixed monday i'm going to be contacting a lawyer and having the shop teacher pay for a real mech. to look at it..

what kind of vehicle do you own? Make, model, year...

How bad was it before it was serviced? Was the clutch continually kicking on and off, or just not kicking in at all? Air relatively cool, just not cold?

How long before it blows the fuse?

I wouldn't jump on the shop teacher just yet. Especially if you just starting using/wanting to use the A/C. Recharging a system shouldn't have anything to do with the electrical part of an A/C system, and it looks like that's the type of failure you're having.