I installed a light bar this week and it is making a high pitch squeal coming from the bar itself when turned on. I though it may be a bad ground so I tried wiring it directly to the battery and same thing. I am using a relay and it is a cheap knock amazon bar fyi; my thoughts are this is an issue with the light bar itself. What are your suggestions on how to fix this?

 

I think you would be best to return it. Get them to replace or refund.