1. Caution... U2 should be an automotive-grade LDO or DC-DC chip/circuit, and not a 7805. Some/most automotive-grade chips have a load dump protection (required) and some have reverse polarity protection too.
2. Caution... GP3 (pin 4) of the PIC doesn't seem to have an internal/weak pull-up - may need an external pull-up/resistor here.
3. Note... Probably should add a 0.1uF or 0.01uF ceramic cap near pin 1 of the PIC unless the C2 cap is nearby.
4. Note... Diodes D1 and D2 may not be needed as some 2N7000 have built-in diodes. But anyway, just leave it in there... can bill customer for more
5. Note... 10A current (based on the F2 fuse) on this board requires careful routing of the PCB and adequate width traces or use a power plane for all this (design PCB for 20A).
6. Optional... Maybe it's easier to select a different PIC chip with more pins so that you can do in-circuit programming and reprogramming until you're happy with it. (Maybe add an ICSP pin header if needed.)
7. Optional... Suggest to use some polyswitch instead of fuse (3A 30V for F1, and 9A 30V for F2)
Probably got other stuff that I missed. That was just a casual look at the circuit. Have fun. Good luck. Bye.