Stig2008

My 2008 Mazda 3 automatic seems to have difficulty shifting into 5th gear after it rains (something is obviously getting wet when it should be dry). Also, when I slide the shifter over to M so I can try to change gears manually, the gear indicator that is normally on the dashboard does not illuminate and the manual function is inop.

After a few days, the car drives like normal which tells me that everything has dried off that previously got wet. SO, my question to all of you is this: what could possibly get wet under the hood that would cause this problem?