Car starts fine and runs fine, no codes. Battery is testing . Turn on lights or ac and battery gauge falls to 11 or so volts. Humming/buzzing noise from behind instrument cluster.

 

Battery is good. Turn off lights and ac and battery gauge quickly returns to 13 volts but-- the buzzing humming noise remains and rises and falls with rpm.

 

Hopefully the mods will move this over to the XK8 forum, where you might find someone who's had the problem (this is the XK 2006-onwards crew). I used to own an XK8, but never had that symptom - certainly sound like a short circuit somewhere, but that's just a guess.

 

My first thread, sorry I misplaced it. Another fact is some six inches or more of water accumulated in the triangular space below the brake fluid reservoir because the windshield drain tube was not connected. Maybe that damaged something in this area?

 

No biggie - it's only a problem for you, because fewer people on here have XK8 experience.

I can't quite picture the area you mean, but is there any rust penetration there that might have allowed water through the bulkhead, or any electrical connectors that might have been 'drowned'?

 

Replaced the Alternator; problem solved.

 

Glad you got it sorted. They're nice cars; I had the same model for 13 years, and it was pretty reliable and fun to drive.

 

Moved to XK8/R section and marked as resolved