[chattahoochee]

2009 EX-L with 38,000 miles on it (of course just passed 36k in last month)

As reported by my wife:

"Pulled up to Chick-Fil-a drive through window when all of sudden there was this loud noise from under the car. Loud bang and hissing sound, followed by nasty burning smell. Immediately parked the car and got out, turned off car."

After inspecting for leaks, fire, smoke, found nothing. Started car and observed no problems, drove car home (about 5 miles) and parked it. No idiot light or other problem. A/C is working as are all other driving systems.

Let car sit overnight and the battery was drained such that car would not start (got that clicking sound only) There was enough power to operate the power doors. Disconnected positive battery terminal and charged battery overnight. Battery drew over 8 amps initially but tapered down to zero after overnight charge (seems normal). I'm hoping this is fairly straight forward since there is clearly a short circuit somewhere which should lead me to the problem.

Luckily I just bought the service manual and electrical troubleshooting manual from someone on ebay. So I imagine if I start pulling out fuses in a logical sequence and monitoring the battery drain I should be able to narrow this down. For starters it is something that is in the "always on" circuit path, not switched by the ignition.

Any tips or tricks are appreciated. I wish I had one of those clamp on ammeters, i only have a cheap-o in line VOM ammeter which probably may not handle the current draw.

Thanks,
George

 

[mjody]

Check the clutch on the a/c compressor. With the van turned off the clutch should spin freely. If it is locked to the pulley, then it will cause a current draw and kill the battery quickly. Your a/c will work because the compressor is always on.

 

[New Dad New Van]

Did you break the Alternator/Compressor belt? Does your A/C work?

 

[chattahoochee]

Check the clutch on the a/c compressor. With the van turned off the clutch should spin freely. If it is locked to the pulley, then it will cause a current draw and kill the battery quickly. Your a/c will work because the compressor is always on.

To test this theory, I charged the battery and went for a drive. Sure enough the A/C was blowing cold, while A/C OFF was selected on control panel.

Took a look at the service manual and figured I should be able to confirm this by pulling the fuse for the clutch stator. I pulled it out and noticed the fuse (number 12 in under hood fuse box) was warm to the touch. I tried to put my VOM ammeter in the circuit instead of the fuse and measure current, but it was 0.0 (even reversed). I then put the fuse back in and heard the click of the clutch engaging. Then I put a flashlight on the compressor and pulled and reinserted the fuse and could see the AC clutch disengage and re-engage.

So now for decision time. Bring it to the stealer and try to whine and moan and see if they might "help me out" and fix it for free or at a discount.

I'd rather just fix it myself, but the service manual shows how to replace the
38924-RGL-A02 Stator set, but it assumes it has been removed from the system. Is it possible to replace the stator set without opening up the system and releasing the refrigerant and having to recharge it?

Thanks for the tip mjody, spot-on!

George

 

[mjody]

Sorry, should have been more awake in my answer. It is likely not a a/c clutch issue. Most likely the relay for the coil is stuck in the on position. Try swapping the relay with another one in the underhood fuse box and see if the a/c is normal. Sorry, but can't recall which fuse is for the a/c coil.

 

[chattahoochee]

Sorry for not replying sooner, but swapping the A/C relay with one from the Fans fixed the issue. I later got 3 new relays and replaced them all. No further issues.

 

[EE4Life]

Helpful thread as well.

http://www.odyclub.com/forums/52-2005-2010-odyssey/86959-loud-noise-compressed-air-coming-vicinity-under-ac-compressor.html

 

[skimask]

Kinda makes you wonder where the "loud noise from under the car" & "Loud bang and hissing sound, followed by nasty burning smell" all came from.

Then again, "Pulled up to Chick-Fil-a drive through window" accounts for the nasty burning smell.

EDIT: Disregard...compressor blow off...'derpy der...

 

[chattahoochee]

Good one! r.e. Chick Fil A nasty burning smell

I think the burning smell came from the AC clutch and/or belts, as the relay was failing it probably was engaging and disengaging the clutch or only partially doing so. Like if you rev your engine and (with manual transmission) release the clutch only partially. OK this is total speculation. What I know is that nothing needed to be replaced except the A/C clutch relay.

 

[mjody]

Relay burns out and the clutch sticks on, doesn't cycle like it should. Compressor builds pressure to very high levels till the high pressure relief valve pops. It then dumps excess pressure, which is in the form of refrigerant and oil.

 

[skimask]

Good one! r.e. Chick Fil A nasty burning smell

I think the burning smell came from the AC clutch and/or belts, as the relay was failing it probably was engaging and disengaging the clutch or only partially doing so. Like if you rev your engine and (with manual transmission) release the clutch only partially. OK this is total speculation. What I know is that nothing needed to be replaced except the A/C clutch relay.

And you're likely going to be replacing some R134a and oil this summer when it gets good and hot.

 

[chattahoochee]

Good call skimask! Sure enough when we went on the first road trip when the weather was good and hot, the AC only worked on the passenger side and blew warm on the drivers side. I thought it was a controls issue, but in the end an A/C R134a recharge and leaktest fixed the air, with no leak found.