My 2000 Ford f150 odometer wont turn off with the key out it rained a lot night b4

[dana]

so I think fuse box got wet? My service engine soon light stays on it seems like it keeps reading tps voltage low and tps voltage intermittent and When I got in my truck this morning it took 4 ever 2 start but after about 20 tries it started I just don't know if its the computer that got wet and is going to need replaced if so about how much does 1 cost I've also replaced the tps twice