The clutch gap on the compressor may be out of tolerance causing intermittent AC. Some folks have been successful removing one of the shim to get it back to spec. You may get a little more life out of the AC compressor with this "fix".

 

I am now thinking that it is my front fan that is the problem, not the AC itself. When driving I can feel cold air trickling from the vent even though the fan is not blowing. Any thoughts about an intermittent fan?

 

I think my problem is my front fan and not actually the AC. The back blows steady, but the front comes and goes. Cold air does trickle out of the vent while driving, but not nearly enough. I have replaced the fan relays, no change from that. The fan did kick in once recently from an under the engine bump received while backing over a curb (construction guy). Anything down low that might respond to percussive maintenance? Otherwise I guess the shock was enough to travel to some loose connection elsewhere.
Anyways, I'm puzzled and hot and don't know what to mess with or direct someone else to look into for me. Any ideas?
Thank you.

 

You did not need to open a new thread. I merged them and made the title of your new thread the title of your old thread.

 

If you kick the blower motor housing can you get it to turn on?

 

Thank you. I have the cover off and the blower exposed. Ironically, the blower is working every time I start the van right now so I can't give it the whack test yet, but I'm ready. If the blower starts up with a whack, what exactly have I found out and what is the cure?

 

I assume we're talking about the blower (circulating fan) inside the van? If so, and if it starts with a whack, it probably has worn motor brushes or a bad connection.

 

I am having the same problem. sometimes the front fan comes on after hitting a speed bump/pothole. I drive my van a LOT, as I am an uber driver. I replaced the relays, but no luck there. I am leaning towards just replacing the blower motor and/or the resistor to see if that fixes the problem. If that doesnt work, I'll try the temp control unit, as theyre $30 bucks from LKQ before i give up and take it to a shop!

 

I'm looking up possible causes and now I feel like a hypochondriac hooked on WebMD.
Does my van have an air control module and could it need a software update?

 

not sure what you mean by air control module. a software update on the AC system is highly unlikely in an older vehicle. since your system seems to be blowing cold all the time, and the fan is intermittently working, focus on that. You can take the blower motor resistor out and test it using a multimeter. ill post a link on how to test it. The part is held in by 2 screws and a wire harness, so its really easy to take out. Of course, you could always just replace it if youre not comfortable testing. the resistor is around $50 at oriellys.

testing blower motor resistor:

heres a GREAT video that shows the complete diagnostic process. Granted, its for a newer Accord, but the process is the same. Even the appearance and location of the parts is similar to an Odyssey.

 

I went to the auto parts store to purchase a resistor and blower motor. They had the blower motor in stock, and the resistor will be in tomorrow. I replaced the blower motor already, and it fixed the issue. I have constant cold air. I will also install the resistor tomorrow, as its recommended to replace both together.

Replacing the blower motor is simple, but its a P.I.T.A. The cover pulls off. Unhook the wire harness, then there are 3 screws holding it on place. You can use a torx bit or a 6 sided socket. It will practically fall out on its own. To install the new one, i found it easiest to put the screw in place in the opening thats closet to the seat and door first. itll help you line up the other 2.


best of luck.

 

I read a generic article about air conditioning systems and it mentioned the possibility of an air control module and possible update. I couldn't find anything that says an Odyssey has one, that's why I asked.

This looks like some great info, thank you very much.
Update
This morning the fan did not come on so I gave the blower a Fonzie thump and the fan started right up. Now I know where to start to pinpoint the fix AND I can have AC in the meantime. I call that a win even before I get to the actual repair.
Thanks for the help folks.