I've retrofitted an automatic HVAC system from a Kia Optima into my vehicle and everything has been going great, but I can't figure out how to get the fan speed control to work.
Here is the circuit diagram not sure how much it will help.
http://dl.dropbox.com/u/800458/Untitled-1%20%282%29.jpg
I don't have the actual Kia transistor, and the people who work for Kia don't even know what I'm talking about when I try to buy one, so I am left to my own devices (literally).
I have a 2n3055 NPN connected to my fan. Collector is connected to the ground side of the fan motor, Emitter was connected directly to ground of the vehicle.
The base was connected to a 1W, 25Ω to 1kΩ potentiometer and I was able to get the fan to turn on and modulate speed. Great, but the output from the auto HVAC unit is too small to turn the 2n3055 on.
So I picked up a 2n2926 and hooked it to the 2n3055 in a darlinton pair configuration. (The emitter of the 2n2926 connected to the base of the 2n3055)
I connected the pot to the 2n2926 in the same way as previously and it SMOKED my pot. So I am a little hesitant to connect it to a very expensive control unit.
Can anyone advise what I should do here? I can test the values of the two wires (gray/blk and blk), but I don't know what to measure for.
How can I protect the control unit from smoking when I finally hook this stuff up?
Thanks.
Here is the circuit diagram not sure how much it will help.
http://dl.dropbox.com/u/800458/Untitled-1%20%282%29.jpg
I don't have the actual Kia transistor, and the people who work for Kia don't even know what I'm talking about when I try to buy one, so I am left to my own devices (literally).
I have a 2n3055 NPN connected to my fan. Collector is connected to the ground side of the fan motor, Emitter was connected directly to ground of the vehicle.
The base was connected to a 1W, 25Ω to 1kΩ potentiometer and I was able to get the fan to turn on and modulate speed. Great, but the output from the auto HVAC unit is too small to turn the 2n3055 on.
So I picked up a 2n2926 and hooked it to the 2n3055 in a darlinton pair configuration. (The emitter of the 2n2926 connected to the base of the 2n3055)
I connected the pot to the 2n2926 in the same way as previously and it SMOKED my pot. So I am a little hesitant to connect it to a very expensive control unit.
Can anyone advise what I should do here? I can test the values of the two wires (gray/blk and blk), but I don't know what to measure for.
How can I protect the control unit from smoking when I finally hook this stuff up?
Thanks.