2005 OB Limited 2.5. Getting a P0692 error code. Traced it to sub fan relay. The relay will not energize (no control signal coming from ECU to pull it to ground), hence no radiator fan. The other fan works fine. Both fans actually work, sub fan relay works, car wiring is good and no blown fuses. So I traced the issue to the ECU and I'm fairly certain it's a bad transistor on the board not pulling sub fan relay coil to ground. I've identified which component it should be, but the only marking on the chip is GA4Z. There's no company logo. My bet is if I replace this chip which probably costs around $0.25 the radiator fan will work and clear the P0692 code. Any suggestions?? Any schematics or bill or materials for the ECU out there somewhere? I can't find anything on that or this chip which is probably a mosfet....Thanks.