05 grand caravan 3.3L keeps burning up a/c clutch

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#1
Van is on #6 Murray a/c compressor (new never reman!) Keeps burning clutch this one lasted 3 miles. Van has correct charge no debris in system always put on 20 minute minimum vacuum time before charging. A/c clutch just seems to fail consistently. Anyone else come accross tjis?

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#2
Have not seen repeated failure....

I will add some thoughts,
Air gap,
Circuit checked - 12v DVOM (not test lamp), AMPs draw, and ground is OK , diode ?
Nothing else on circuit from relay?
no voltage on grd circuit
It does cycle ? What is High ?

Draw
Denso 10S17 – 3.3 amps @ 12V ±
0.5V @ 21° C (70° F)
Denso 10S20 – 2.2 amps @ 12V ± WITH REAR AC
0.5V @ 21° C (70° F)
Compressor Clutch Air
Gap
0.35 - 0.60 mm (0.014 - 0.024 in.)
 

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#3
Vans scheduled for monday afternoon. Will check electrical and repost. Thnx for input!!!

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#4
I would like to see some colleagues opinions on 'murray' replacement parts as opposed to denso.

Also there is this tidbit I found
 

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billr

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#5
Clarify: is the clutch coil burning up, going open-circuit? Or, is the clutch friction surface disappearing? Or, is the friction surface OK but the mating bare steel parts getting warped? My guess is you have a poor connection in the wiring and voltage to the coil isn't the full 12V (nominal). Check all that as already suggested.
 
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#6
Heading out to trailer van back to shop, thankyou all for suggestions. Will update when i know more

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#7
Ok got it back and we are getting 13.5v @ clutch with engine running. But clutch is burned and not engaging compressor

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jd

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#10
Volts isn't Amps. 50PSI water to a Garden Hose is different than 50PSI to a Fire Hose. If this thing is burning CLUTCHES, I'd wire a Relay right at it. Whatever circuit is powering the Clutch now, energizes a Relay that gets its power from the Battery via a Fuse. Did this on a van years ago. Completely different vehicle, a Dodge with an aftermarket A/C using a York two-cylinder compressor. But it kept the clutch engaged and I had no trouble the rest of the time we had the van.


Relay pictured has Normally Closed Terminal 87A, you wouldn't use it for this job.
 
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#11
Friction surface disappears. Lets out a nice cloud, and makes for a pisst off customer.lol


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#12
I'm assuming that if the compressors were locking up internally, you would have mentioned it, so...JD's idea of setting up a relay to assure adequate power to maintain full clutch engagement would be something to consider.
Another possibility would be a batch of clutches with crappy "rubber springs". But I think I see heat from slippage and if the rubber part broke, the plate would not get hot like that.
 
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#13
I get what jd said but im getting full voltage to clutch so dont quite understand how a relay will help

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billr

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#14
Just for fun, how about measuring the current draw of that clutch coil? And, what is the DC resistance of it when cold?

Can you take the clutch apart and take pictures of the damaged parts "spread out"? I'm not familiar with how that clutch is constructed, not sure what I am seeing in the picture posted.
 
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#15
interesting -
You said 6 new compressors (post 1)?
Are the clutches coming on the compressors OR are you installing them?
What is history - customer brings in with just a bad AC clutch OR more to this.