My son took his car to school. Had no problem with his car. Went to lunch off campas,came back still everything fine. School ended car would not turn over or crank.
I thought battery. I jumped the battery and nothing. I took the 50 amp ignition fuse out and switched it with the 50 amp optoin fuse car started. Turned car off and took old ignition fuse put back into the option location closed the hood car wouldn't start. Took the option 50 amp fuse out car start and runs fine. Went to the part store got new 50 amp fuse put into option location again car would not start. Take new fuse out, car starts. Can anyone help with this problem. Do I need the 50 amp fuse on the option or can he drive with out it ? It seems everything is working on the car without the 50amp option fuse in there.

Under hood Option Fuse No. 36 (50A) protects under dash fuses No. 1 (Moonroof motor), No. 3 (Integrated control unit, Ceiling light), No. 6 (Power door lock control unit) and the power window relay.

It's there for a purpose and I would try and get to the bottom of why it started causing a problem--you'll be glad you did. That fuse protects the Integrated Control Unit (ICU)--bulb check circuit (brake system light), seat belt reminder/key-in beeper circuit, and intermittent wiper relay circuit. This is an important circuit board that has an internal connection to the Bulb Check Circuit, which includes the Starter Signal. Problems here can prevent the car from starting.

The flow is + battery to under hood fuse No. 41 (80A) to under hood fuse No. 36 (50A) to under dash fuse No. 3 (7.5A) to the ICU. To me, it seems like removing the Options fuse No. 36 should cause problems, not solve them. Something very unusual is going on here. I would definitely pursue it.

Were do you recommend starting? With the ICU? And how much will a new ICU cost? Buy the way thanks for your response
Tony

I would focus on the ICU, even though I have never seen this problem before. It could be a bad printed circuit board (PCB). No idea of the cost. Try troubleshooting everything, before buying a new PCB.