Dash lights flash when it gets windy underneath or speed??

So I'm slowly getting to the stage where my Super Custom is looking like I want it to but!!....

Its always done it but when I'm on the motorway or pushing on some dash lights come on, not all of them just the rear parking sensor, engine over heating and no oil and something else I can't decide what it is? but my question is, is this a problem anyone else has had? I've been underneath poking wiring and bits while someone's been in the van and nothing flashes. It doesn't stay on at high speed just when i hit cross winds or it's more windy than normal. It doesn't affect the drive at all, no lose of power or side effects.

It's probably something I could live but I'm worried it's harming something and it's not great for passengers seeing the dash light up :p

Do we think I'll need to bite the bullet and call an auto electrican?

Cheers in advance.