Backup light blues

[DRWBRTq19]

Working on a '98 GP GT, anytime I shift into reverse I blow the backup lamp fuse.
I was originally thinking short but it has been suggested that it might be a bad ground.
Does anyone know where this systems ground is?
And as I'm horrible with electrical problems if anyone has other*opinions/options/suggestions I'm all ears.

Thanks in advance.
Drew

 

[MoarkatsINmuhtrailer]

definitely sounds like a ground..

check the harness at the lights. i think it should be back there under the trunk matting maybe

 

[TLSheff]

Also check the lights and make sure you don't have corrosion building up between the points, if they have anything connect them it can cause a short and the fuse to blow. Just an easy pull the bulbs and inspect the socket check over. Often simple things tend to be the culprit.