Hold up is it electrical or mechanical ?

he mentions sender so should be electrical

What method do u use for senders mick ?

Loctite sell a chapstick style sealer that is conductive and works a treat

Thread tape is ok but I found if u put to much on it insulates the ground from the sender

Gauge is electric

dont rule out it may be a dud gauge, and youve done everything right. If its new, swap it and start again. that's if the shop is fair dinkum, and not ebay I hope.{for less dramas}

What J@SNOT said!