Squealing noise from alternator or belts when pop up lights up?

Technical Area Engine, Transmission, Exhaust etc
2

 Hello all, just noticed squealing noise from engine bay when I put the pop up lights up and on. Lights down, noise goes, up noise back, down noise goes etc etc. Is it the extra load on alternator, any ideas please.Can’t see how light mechanism could affect belt.

Cheers

Ray

3

 It’s the drive belt tension.  Extra electrical load causes ‘drag’ on alternator, belt slips and squeals.  Check belt is OK, either replace belt if worn or retension old belt.