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My wife's 05 MDX has been dying over the night and we've had the battery and alternator tested and both are good.

I did the test where you hook up a multi meter to show current between the negative terminal and negative cable and pulled the fuses and found that the car was pulling around .65 amps until I pulled the fuse labeled MG Clutch and it dropped to arpund .13 amps.

I'm trying to search now but if anyone could give me a hand and let me know what the mg clutch is and what I need to do to fix this parasitic draw it would be a great help.
 

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Are you doing the test with the key off (and out of the slot)? Even 0.13 amps is more than normal.

I'm not sure what the "MG Clutch" is (and there's no reference to that in the manual, at least not one I could find searching on that term), but there are electronic clutches on the A/C compressor and in the rear differential.
 

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The car is dead and the key is out of the ignition when Im doing the test. I think I may have read the multimeter wrong as i was getting around -0.65 and around -0.13; I'm not sure if that matters or not.

I also found this video that also had me check the MG Clutch relay which was next to the fuse and it also yields the same results when both the fuse and relay are taken out.

So I'm gonna try replacing that relay if I don't find anything else.
 

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How are you measuring the draw? The meter needs to be wired in series with the battery, not in parallel! Are you measuring on the positive side or negative side?

the current with the car off and locked should be 20-40 miliamps MAX! .13A is 130 miliamps which is very high!

MG clutch according to a quick google is the A/C relay so it may be stuck on.

Also the Handsfreelink system tends to go bad over time and increase the draw. Most folks simply unplug the unit so they dont have to deal with replacing it and a dead battery.

Highly recommend you replace the faulty relay (or blower motor transistor depending on which is faulty) and disconnect the HFL and retest. Unplugging fuses helps quite a bit to narrow down the bad circuit.
 

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phatjames167, I wouldn't worry about the "-" sign... it just means that the leads are reversed (the current is the same either way). And FWIW, it doesn't really matter if you measure the current on the negative or positive side - the current is the same (an electrical "circuit" is really a "loop", so what goes out one lead ends up coming back on the other... an oversimplification, but you get the idea).

If the stuck MG clutch really is the A/C clutch (which makes sense), you should be able to see the front of the A/C compressor spinning with the belt with the car idling and the A/C off. If unplugging the MG Clutch relay disengages the clutch, it's likely you've found the problem. Of course, it could also be another electrical problem turning the relay on (you can check this by throwing a meter across the coil contacts in the plug with the relay removed... if there's 12V DC there, you know the problem is elsewhere). But if there's no voltage across the relay coil AND removing it disengages your A/C compressor clutch, you've found an easy fix.

I agree with csmeance that .13 amps (130 milliamps) is too high - I wonder if you have the door open while you're doing the test... (dome light?). But even then, a 130 amp drain isn't nearly enough to kill your battery overnight.
 

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The MG clutch is the magnetic clutch on the AC compressor.

There is nothing wrong with the AC. The relay failed in the closed position and it keeps feeding the AC compressor clutch.

You need to replace that relay.
 
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