Based on all the problems they've had with computers in the past, I'd start by unplugging the radiator fan relay. It's a small electronic module by the side of the radiator. Other items on that fuse include the fuel system leak detection pump, torque converter clutch solenoid, fuel pump relay, ac compressor clutch relay, and anti-lock brake computer.
The leak detection pump runs right after starting the engine, the fuel pump runs all the time, and the torque converter clutch operates above 45 mph in 3rd or 4th gear. All of those are working based on the fact the fuse takes so long to pop. What is likely is the radiator fan turning on at low speeds such as city driving after the engine is warmed up. On the highway, air flow is more than high enough to cool the radiator, so the fan won't turn on. If you have anti-lock brakes, you have a system with a pump that never runs until the anti-lock function is needed. If you have ABS, drive on a dirt road and hit the brakes hard to activate the system. If that makes the fuse blow, suspect the anti-lock computer. I'm still leaning toward the radiator fan relay, because I'm pretty sure this fuse only powers the part of the ABS circuit that monitors the wheel speed sensors, and that circuit runs all the time.
Saturday, April 18th, 2009 AT 2:54 AM