Vauxhall Vivaro head lights and dash board lights blink

Check earth wires at h/lamp and also from engine to body .

Further to Whightehame's suggestion,there's an earth cluster on the chassis leg behind the n/s headlight,they can do crazy things if this is poor.
If it is a short on the wiper mechanism don't be put off,the whole wiper motor mounting plate from wing to wing comes off with ease,doen't look it but it does.L and R screen trim,then plastic panel then some 8 or so torx screws and multiplug and it's off,an hour tops.
a lot easier to work on then.

had same problem.Left it until indicators came on its own and would switch off. Fault codes showed fault with module, but replacing indicator stalk solved indicator and blinking light faults.