Hello everyone,
I'm new to the forum but have spent many hours on here on the journey to fix/restore my 2005 xk8 to its former days of glory. I have completed many projects including a full suspension/bushing rebuild, zf 6hp fluid change and seal replacement, oil/trans pan, and general tune up. No matter what problem I ran into, I would always find an answer in a forum...until now.

Fuse #3 in the engine compartment constantly blows. I got educated and learned that fuse #3 feeds nine different circuits(fogs, heater, headlamp actuator, etc) from reading the 2003 xk range electrical diagram. Ended up deciding to disconnect all the things leading to fuse #3: fogs were disconnected at the harness(water?), security sounder near right headlight, heater relay, front fog relay. Was certain that the fuse wouldn't blow...but it DID!
I'm not quite sure what the deal is since the center console switch bar (heated seats, fogs, etc) does not light up but the accessories themselves work. No fogs, no heater (unless youre going 60 mph+, barely). Also, the front right headlamp will sometimes blink/turn off randomly and then come back on. Same with the rear side stop lamps: the rear left worked and now only the right side works. Besides this there seem to be no other issues...cars awesome!

If anyone has any ideas then id love to hear em. I'm currently working on checking the grounds connecting to all of the individual circuits that are fed by fuse 3.

 

You could remove the fuse and check to see the resistance between the 'outbound' side of the fuse (i.e. the side protecting all the things that need protecting) and ground. If it's not infinite, there's something still out there, including the short to ground you perhaps have on that side.