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2003-2007 HVAC Blower Transistor Repair

Old 03-01-2011, 05:13 PM
Thread Starter
Join Date: Feb 2011
Posts: 2

The blower motor on my 2004 Accord decieded to stop working in middle of this bone cold winter - I found this step by step fix with photos on and it worked like a charm. I first tried the fuses, relays, banging the bottom of the blower motor, seeing if the blower motor had a short and checking the code off the radio display all items that were suggested to try first. When none of that worked I took the plung at this fix even though my auto mechanic skills are very limited and the results were great. Easy instructions with great photos, I tested the resistor and it was bad - ordered the part $68 and had the part back in and the blower motor was back up and running.

You have two options, replace the transistor with a new one, or solder in a new fuse and replace the heatsink compound in the old one.

If you are replacing the whole transistor, you can ignore the last part of the instructions to take apart the transistor. I also noted this in the instructions.

The OEM part number for a new a/c power transistor is for 03-07 accords: 79330-SDA-A01

Here is a good YouTube Video on how to remove the transistor.

DIY- How to Remove and Repair the AC power transistor

User is presumed to have a fair level of mechanical or auto electrical skill in doing this DIY. The author shall not in any way be held responsible for any damage resulting from user’s fault or failure to follow the suggested steps proposed by the author. It’s the user’s responsibility to research thoroughly on the project and validate this DIY.

This DIY based on the three items that I repaired before so I presumed that once the AC
blower on your EM/ES is not working the AC power transistor might be the cause of the problem. IF IT HAPPENS THAT THE REPAIR ISN'T SUCCESSFUL, THERE MIGHT BE ANOTHER PART THAT NEED TO BE FIXED. Please refer to your local dealer or reputable mechanic for further diagnosis.

Tools and Materials:

• Philips screwdriver

• a Tweezer
• Soldering iron and lead set
• a thermal fuse (2 amp, 114 degrees Celsius, glass type)
• Heatsink compound

You will find the AC power transistor module here.

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Removing the AC
blower cover isn't that difficult, see the pics below.
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The defective part.

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Remove two screws.

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Now release the lock to remove the AC power transistor module from the connector.
If you are planning on swapping out the transistor with a new one, just plug in the new part and reassemble everything in reverse order.
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Notice the heatsink, the power transistor itself and the thermistor are attached to it.

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Using the tweezer release the hooks to open it. refer to below pics.

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That's the thermistor its a PTC(positive temperature coefficient-the resistance increases with increasing temperature) check with DMM it must be shorted or have at least 0 to 2 ohm resistance depending on the temperature of the heatsink.

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If it's open or no resistance at all, replace it with a new thermal fuse.
DO NOT REPLACE WITH A RESISTOR AS SHOWN IN THE PICTURE BELOW. Get the thermal fuse listed at the beginning, or some equivalent. De-solder the five solder joints shown in the picture above. Then you can lift the circuit board up. There should be a screw holding the fuse in place that you need to remove. Clean up the old heatsink compound, add new heatsink, bend the fuse leads like the original fuse, set the new fuse in place, then put the clamp and screw back on. Put the board back on top, then solder all five joints back to the board.

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Assemble in the reverse order of removal and re-install the power transistor.

Hope you like it

One of a happy fella who tried already this DIY:

Last edited by PAhonda; 06-29-2011 at 11:37 PM.
Old 06-23-2011, 06:23 PM
Join Date: Jun 2011
Posts: 2

Dude, this so just saved my CAN
My wife's car has a/c again, and it all because of this step bt step instructions of testing and replacing this part. Thank you
Old 07-10-2011, 12:04 PM
Join Date: Jul 2011
Location: Houston
Posts: 1

My blower stoped working. How do I test the a/c power transistor ?
Old 07-11-2011, 05:00 PM
Super Moderator
Join Date: Sep 2006
Location: Houston, TX
Posts: 13,077

There is a HVAC codes thread in the DIY section. See what codes you get.
Old 07-28-2011, 06:33 PM
Join Date: Jul 2011
Posts: 3
Default Well, new one lasted about 10 minutes

I read all these threads, and was so excited that I went ahead and plunked down the $69.00 for a new one and slapped it in the car. Worked great for about 10 minutes, until the car just about had cooled off. It's only 102 here in Dallas today.

So, I stopped at the corner Radio SHack and grabbed a couple of fuses and changed it, and now, the fan runs on high as soon as I turn the ignition on. I still get a code N on the diagnostics test.

Any ideas where to go next?

I'm changing the fuse on the original one now.
Old 07-28-2011, 06:59 PM
Join Date: Jul 2011
Posts: 3
Default Well, now I have TWO transistors that overheat

I just re-fused the original one and stuck it in and same symptom. Fan runs as soon as the ignition is on, diags give an N, and the transistor gets hot enough to burn you in under a minute. I assume the fuse will give up if I leave it on, so.....

What next?
Old 08-02-2011, 01:20 PM
Join Date: Aug 2011
Posts: 7

Originally Posted by gregjtx View Post
I just re-fused the original one and stuck it in and same symptom. Fan runs as soon as the ignition is on, diags give an N, and the transistor gets hot enough to burn you in under a minute. I assume the fuse will give up if I leave it on, so.....

What next?
Greg, I have the same problem on my 2003 Accord EXL 4dr 6cyl. I replaced the resister, and yesterday it worked fine. Today the blower goes and goes and the AC Cools great, but I want to turn the fan either down, or off at some point. Will be waiting for a reply... I think I need a new blower motor???
Old 08-03-2011, 05:40 AM
Join Date: Jul 2011
Posts: 3
Default I gave up and bought a new car!

I'd had this one 9 years, 86,000 miles, needed tires, bent on the front and back, and now AC issues.

Decided it was time to start fresh.
Old 08-04-2011, 08:00 AM
Join Date: Aug 2011
Posts: 7

The part that I bought was bad. I took it back since it had a lifetime warranty and they replaced it free. I got it installed in less than 5 minutes and the air is blowing strong and cool. I have AC and everything is working fine.

I have 182,000 + miles and going strong. That said, my next car is another Toyota. I have had 8 Toyotas now and have had experience with two Honda's.

Bottom line, I'll never own another Honda.
Old 05-16-2012, 03:32 PM
Join Date: May 2012
Posts: 1

Been looking all over hell trying to find the right thermal fuse. The one I took from mine is 140C ; 2 Amp. All the places I check are not the same and rated for A/C not D/C and nothing at the 2 Amp range. Any help where to go an get one?


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