I have a 2005 Accord EX the cabin fan stopped working. I have 12.5 votls to it and it works when I connect the battery to it. Any one know the problem?

 

It is likely the transistor. It is similar in function to the resistor on older accords. There is also a writeup in the DIY section about HVAC codes you should check out.

 

The code that comes up is "N".

 

Ok, that is a problem in the blower motor circuit. This problem has been popping up recently on 03 accords, so an 05 doesn't surprise me, since it is the same generation accord.

You have two options:

1. replace the transistor ~$80 for the part. Pretty simple DIY.
2. solder a new fuse and controller (~$15 for parts). Simple to if you know how to solder.

Here is a thread dealing with the same problem as you. Poster opted to replace the unit.

https://www.hondaaccordforum.com/for...ad.php?t=34292

 

Maybe i am missing something......if you have 12.5 volts to it , why are you also applying battery to it........
you got 2 wires to motor .........power side white/blue.. should have voltage

ground side blue/black,, should have ground,,
If no ground most likely it is a bad transistor i have seen many go bad..
make sure that you got ground at black wire going into transistor .. if you do and no ground at blue/black ,,,99.9% it is a bad transistor,,

 

Check this out too.
https://www.hondaaccordforum.com/for...ad.php?t=36131

 

Interesting, My wife recently purchased a 2003 Acura MDX (ebay). We had an inspection done and some maintenance performed, but car basically checked out good. On way home from Dallas, I noticed the rear AC wasn't wasn't working (no blower).

I participate in an Acura MDX forum and they have found that rear AC power transistor thermal fuse frequently fails also. However they have a reason for the failure. There is a cooling air intake for the power transistor that get's covered w/ "car fuzz"; hair, dust, carpet debris, etc. The Accords don't appear to have this arrangement so why do the thermal fuses open? It could be related to low air flow through the cabin air filter. Perhaps a dirty cabin air filter hastens this failure. I'm speculating here that cabin air flow cools the power transistor. It was not evident from the shop manual whether this is case or not.

good luck