Thermostat can be traced from the thermister that is installed in the evaporator box housing. It should be close by.

When you checked the ac diode, were you measuring resistance on max scale? In that case, the needle should swing to right indicating high resistance. In other direction of probes, the needle should remain near short condition on same scale (low resistance).

When you replaced the AC diode, does the same behavior occur w/ fans only coming on when you short thermoswitch A?

good luck

 

Yes, the same thing happens with the diode replaced. I came to find out that my original Diode was never bad in the first place. I had measured resistance across the diode in both directions on max range on my multimeter, and it showed overload/infinity in both directions, leading me to assume it had burned up. Well, I bought a new one and still had the same problem, and after testing the new diode saw that it showed the same high resistance in both directions. After reading up a little more on it I found this article:

Testing Diodes

Which explains that the voltages used in many multimeters for resistance calculations are not high enough to overcome the forward junction potential of the diode and allow current to flow. You have to use the diode setting on the multimeter in order for it to measure. So it was operator error with the multimeter that was leading me to believe that the diode was bad. For everyone's reference, the reading given on the diode setting on the multimeter is not actually ohms (resistance) but rather millivolts of voltage drop across the diode.

Anyway, I just figured I would take time to explain why I was thinking the diode was bad.

Thanks again all, will keep you posted.

 

Forgot to finish off this thread with the resolution. The A/C thermostat was the culprit. Went to the junkyard and had my pick of the litter for $5. It was difficult to remove the thermostat probe from in between the fins of the evaporator as i was not able to remove the bottom half of the blower and evap case completely (removed all the bolts I could get to but there were still 2 up back behind it at the parting line of the case. I could not even see them let alone get a socket on them.) But with the front bolts of the plastic case removed I was able to pry the two halves apart enough to reach in and pop the thermostat probe out. Once I replaced the A/C thermostat, the ground signal that comes through the blower speed switch and the A/C on/off button was able to continue through the thermostat. Our A/C once again blows nice and breezy. Thanks to all for the great knowledge base on this forum.

Until next time, dudes.

 

Thanks for coming back with the "end of the story". Too many times these threads just go dead and we never know.

 

To the OP, hopefully you might get an email notification to a reply in this thread...
Where did you find your diode, can you take a pic if you still have the Accord?

 

I did get an email! Nice. Unfortunately I sold the car about a year ago, but after looking through the shop manual it jogged my memory. I believe The AC Diode is inside the cabin, up under the drivers side dash, like by all the wires from the gauge cluster. I want to say that the Diode is in a plastic housing with wires going into and out of it, which themselves jut out the side of a wire loom/bundle up under there. I cant tell you what color the wires are though. Just look for something that looks like it does in the attached picture. the plastic housing holds the diode.