Thanks Mr Chips, I used transistor tester it says PNP transistor but you are saying switching diode, it's new thing for me, how they work?Welcome to AAC!
You used a transistor tester to identify a component and this is the result it is showing you?
Try Siemens BAW78A 50V 1A switching diodes.
The pin two which initially I thought was gate of n channel mosfet is connected to relay of fan. Relay trigger second pole is battery positive. I was sure this was n channel mosfet and replaced one but check engine light came. It is not mosfet I think.I would not trust a transistor tester 100%.
Show us sharp close-up photos of the good component and the bad component.
Also show us a clear photo of the whole board.
Check if you get the idea https://www.dhgate.com/product/ga-mazda-323-fumei-to-the-computer-board/402626182.htmlCould it be a 2SA1871? (although it should be marked GA1, GA2 or GA3 according to gain group)
I am not sure that is why I am asking experts like you.This begs multiple questions.
1) How can you be so sure that it is a PNP transistor?
2) What are the markings on the good component and the bad component?
3) Are you testing the "good" component in-circuit or off the board?
4) What are the voltages on each pin with respect to ground on the good component on the working board?
If it is a transistor in an SOT-89 package and the emitter at pin-3 is connected to GND then I would think it is an NPN transistor, not PNP.
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Thanks for all the efforts.