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So I had problems with the blower not working so I replaced the blower transistor. This worked for about 15 minutes and the blower turned off. Now what's the problem? Obviously there's a bigger problem than the transistor but did I blow the transistor I just bought? I bought it from partsgeek.com and made sure it was compatible with my car and it even looked the same as the old one. What's the deal?

 
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https://www.civicforums.com/forums/3...-02-civic.html

Doing this test will tell you if the TCO has opened.

 
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Not sure if it means anything but when I unplugged the new one it was really warm.

 
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Sorry but I don't know what the TCO means. I'll check the cabin filter but if it doesn't spin what does that tell me? My hunch is that it isn't.

 
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Set the fan to med speed, lower glove box and remove cabin filter. Closely watch white squirrel cage fan as you turn key to II....

Does the fan spin for a very short time then stop ??

 
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I'm at work till midnight now but I will check in the am. Thanks for your help!

 
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I just checked and it doesn't move at all. The only thing is I'm not sure if it's because the new transistor might be busted. Like I said it worked for about 15 minutes then stopped

 
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I think TCO means the thermal fuse that is inside the power transistor assembly. It blows when the unit is overheated for any reason....and they sometimes blow just from age.


The power transistor assembly can get hot during operation. That's why it has a large heat sink attached to it and it's mounted in the fan housing so it can be cooled by air coming directly off of the fan blades.


If you didn't have the power transistor mounted in its little hole in the ductwork, it can get overheated and damaged.

If the fan motor is drawing too many amps, it can damage the power transistor.

If the cabin filter is clogged or there is any other reason the fan can't blow sufficient amounts of air, the power transistor can overheat and get damaged.





I'd probably jump the 2 large wires at the power transistor plug and see if the fan still runs, and note how well it runs. Then measure the amp draw of the fan motor.

 
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Yeap, I bet that's what happened.

 
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I bet the transistor did over heat because I did get lazy and had it just dangling down till I got to work and that's when it took a dump. Looks like I'll be ordering another one!

 
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I bet the transistor did over heat because I did get lazy and had it just dangling down till I got to work and that's when it took a dump. Looks like I'll be ordering another one!

 
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Expensive lesson...

 
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$30 part. Will spend $60 total but still better than taking it to the shop.

 
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If the TCO is open.... the blower should turn just a tiny bit in the test I posted. Could be another component failed without cooling.

Let us know the results.

 
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Correct! See: http://www.acronymfinder.com/Thermal...%28TCO%29.html

 
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Another cause is neglect of cabin filter. Reduced cooling to transistor and the tco opens.