# Help! A/C won't work after engine overheat. Blowing compressor fuse



## bk2futr (Aug 20, 2016)

My lower coolant hose came off yesterday and caused me to get an "engine overheat" warning on the dash so I pulled over and let everything cool down and fixed the hose and add new coolant. I was almost home when it happened so not a huge deal

Well now for some reason the A/C compressor isn't working ...Checked the fuse and it is blown Tried replacing and it blows instantly as soon as I turn on the AC,. the clutch spins free so I am thinking I have a short.

Not sure if something got wet from the antifreeze or what but you would think the sensors and other things there could get wet without hurting anything.

Any ideas>?


----------



## Tomko (Jun 1, 2013)

I agree. Steam or vapour causing a short. Time to bring it to the dealer. 

How the heck did a rad hose suddenly blow off? If it were to go, it would have been in the first 100 miles of the car's life.


----------



## ChevyGuy (Dec 13, 2014)

Given that's it's blowing a fuse, it's time to look for a short. Perhaps the hot coolant melted the insulation on a wire causing it to short to ground. I really can't see any kind of compressor malfunction doing it, so I'm thinking it has to be a short.


----------



## bk2futr (Aug 20, 2016)

Thanks...only place I can see that really had coolant on it would be that sensor right on the radiator beside the hose. Think if this was shorted it would cause it to.blow the compressor fuse?


----------



## ChevyGuy (Dec 13, 2014)

bk2futr said:


> Think if this was shorted it would cause it to.blow the compressor fuse?


No. It would have to be a shorted compressor clutch coil or the wire to it.


----------



## NickD (Dec 10, 2011)

About the only time a blown fuse is not a problem is connecting a trailer to your vehicle and not increasing the size of that fuse to handle the extra load. For anything else, is a major problem. 

Had problems with clutch compressor coil before, if they were layer wound and dipped in an insulating varnish would never be a problem, but are raw magnet random wound coils were vibration rubs off that thin magnet wire enamel causing internal shorts.

Use to be cheap to buy and replace, but outrageous today, cheaper to buy a new compressor with a new clutch coil unless you are handy and can rewind that coils yourself.

But the clutch coil is not the only electrical, the old V4's variable displacement compressors were mechanically controlled, these new one are electrically controlled. They don't give specs on the current draw, so have to figure out this for yourself. 

Hooking up a lab type power supply the general current at 14.5V is about 4 amps, but leaving it on for about 15 minutes, the coil should heat up, increases the resistance of the coil so it should drop to about 3.5 amps. With a bad coil, that expansion will increase the current draw and even enough to blow the fuse.


----------



## ChevyGuy (Dec 13, 2014)

NickD said:


> But the clutch coil is not the only electrical, the old V4's variable displacement compressors were mechanically controlled, these new one are electrically controlled. They don't give specs on the current draw, so have to figure out this for yourself.


As far as I can tell, the variable displacement is handled by the ECM. Only the clutch is goes though what I'd think would be called the compressor fuse. So, I think it's the clutch coil or clutch coil circuit.


----------



## bk2futr (Aug 20, 2016)

Thanks for all the replies guys! I did find the issue the wires were shorting out against the compressor. Look like the bracket got bent back and rubbed the insulation off the wires eventually. Now this car was a wreck at one time which was probably the issue... when the ac lines were hooked back up nobody caught the fact that the wires and bracket were bent back. So I replaced the compressor with a used one and recharged the system and now all is ok. Thanks again for all the replies. I really appreciate it.


----------



## Tomko (Jun 1, 2013)

bk2futr said:


> Thanks for all the replies guys! I did find the issue the wires were shorting out against the compressor. Look like the bracket got bent back and rubbed the insulation off the wires eventually. Now this car was a wreck at one time which was probably the issue... when the ac lines were hooked back up nobody caught the fact that the wires and bracket were bent back. So I replaced the compressor with a used one and recharged the system and now all is ok. Thanks again for all the replies. I really appreciate it.


Glad it got fixed. 

However, the fact that this car was a was a wreck is a vital piece of information that should have been included in your very first message. It also explains how the rad hose managed to blow off: it was improperly installed by whoever rebuilt the car.


----------

