By keeps I mean its the second time but still more than it should in less than a year. Shouldn't there be smaller fuses that should blow before it? if not what troubleshooting can i do without going through a ton of fuses to do it? (Its the big fuse at the back of the engine bay, not cheap to replace if i have to do it multiple times.
That's good, it means the fuse is doing its job & protecting the wiring circuit. A fuse will blow when the current draw (amps) exceeds the rating of the fuse (amps). Therefore there is something wrong in the circuit, this could be defective wiring, defective fan etc. Would recommend a current load test on the circuit, with everything operating at maximum, the load should be less than 45amps (if that is the correct fuse). Unfortunately a standard multimeter won't read amperage above 10amps without additional equipment.
Referring to the wiring diagram. The wiring goes to the Stop Light Switch & the Shift Lock Control Unit (if it's an Auto). These circuits are protected by a 20A fuse (after the 45A fuse). The wiring also goes to the Radiator Fan Relay, the radiator fan motor would be a good place to start diagnostics. Run the fan at high speed & check the current draw. If the fan checks out OK, there could be an issue with the wiring.
Don't replace fuse yet. Before i get too technical can you tell me the steps you go through up untill the fuse blows? EG: start the car and the fuse blows immediately or you start the car and the fan starts a bit then stops and the fuse is blown. That sort of thing. I need to know under what circumstances the fuse blew and when and how you realised the fuse was blown? MichaelZ
