I have a 2000 Ford F150 and the #15 fuse keeps blowing even with the key off. It say thet it is for my stop lamp switch ( spped control, brake shift interlock), GEM module, and RABS module. Any help is appereated

Did this start happening after wet weather ? Ihave read several instances where water get in past the windshield weather stripping and into the fuse block.

If it's the fuse for the cruise control, I'd quit replacing the fuse and have a dealer's shop check the cruise control pressure switch.

My 2000 F150 caught fire and the source was the cruise control pressure switch located on the master cylinder. There's a recall on this part.

Do not park in a garage or under a carport until you've ruled out the cruise control issue.

Mine caught fire in a parking lot. If it had been at night, the house would have burned.

--
Rick

Take it to an auto electrical shop. They have the equipment to locate the ground out on a hot wire. But, if it were me I would replace the brake light switch on the brake pedal. I's the only moving part in the brake light system. It is grounding a hot wire out blowing the fuse.