Is this for a 1998 Discovery, my husband is saying the location of our panel is different, he says ours is under the glovebox behind the dashboard.

 

As for random electrical issues: the engine ECU can get corroded. Pull out the ECU box and look for corrosion. You can take the board out of the box and make sure it's clean. If the board has started to corrode you will get all sorts of random/unexplainable electrical issues.