Speedo and high beam

[Jasoniumh]

Hey all,
Recently changed motors, new extractors, 2 1/2 sports system to tail. My high beam stoped working one night, cut all headlights out. switch back to low beam and they work fine. On one occassion I was driving out of my driveway when the car lost TOTAL power, I mean everything. Quickly turned off my aircon hoping that might help and presto... she came back to life, stereo reset and everything. Hasn't happened since. On two occassions after driving for a couple of hours my spedo started going weird. jumping then failing then working to jumping and failing.... weird.... Any thoughts?

[immortality]

mysterious electrical fault. check your battery clamps, the stereo only resets if it looses all power. i've had problems with the tacho going nuts when i had left the headlights on and tried to start it on a flat battery. charged battery and it was fine so check the battery condition also and the charging circuit (alternator) it should maintain 14 volts when running with and without a load (turn on all the lights, heater etc to load up the system). with the engine off the battery should maintain 12.3v - 12.5v and it shouldn't drop much below 12volts went starting the car. you need to check all your fuses also with a either a multimeter or a test light, just "looking" unfortunatly doesn't always pick up a blown fuse