[Slackrabbit]

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!

 

[Slackrabbit]

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.

 

[Slackrabbit]

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.