a friend of mine just bought a used 02 f-150. we went fishing the other day and the truck would not engae into 4 wheel drive. it has the manual shift for the transfer case. we managed to get the boat in the lake and when we came back the 4 wheel drive worked fine. drove home and tried it in the drive way and same thing would not work. when hot the 4x4 indicater light won't light up, but when cool it does and works. anyone out there have an idea of what could be wrong. thanks in advance.

 

Hi and welcome to the forum

On the front of the transfer case, above the front driveshaft, is the 4x4 lockout switch. It tells the GEM module when it's in 4x4 so it can turn on the light. If there is any moisture in the switch it can cause the problem you're having. Usually the cure is to change the oil in the transfer case and replace the switch.