I have a 2004 F150 (New Body Style) with 5.4L 3v and about 266k miles. My Alternator finally bit the dust and my instrument cluster went from reading speed, temp level, odometer, RPMs to being blank and all needle gauges bottoming out on the "0" side. Removed Alternator and had it tested, found Alternator Failed tests. Ordered and Installed New aftermarket 110a Alternator. Battery was fully charged (13v) and passed load test out of the truck. After installation, started the truck with no problem, instrument cluster gauges all read normal when turning key to on position, after starting and let run, instruments and gauges blacked out and returned to "0". Battery was reading 13v and with truck running read about 17v. Any Ideas on what could be causing this? Any information in order to resolve this issue is greatly appreciated.

 

The voltage should never read 17 volts. 14-14.5 is the most it should read. Have the new alternator checked.

 

Bingo! The cluster will shut down automatically at just over 16 volts. It sounds like you have a faulty alternator.

 

Along with shutting down the instrument cluster you are also over charging your battery.