Lately when I switch to high beam from low beam, the high beams are bright but once I finish switching them and let go of switch they dim a bit and less concentrated. Any ideas or suggestions, I'm running SilverStar 4000k bulbs.

Possibly not enough power going to them when fully engaged, have you checked voltage on them. Also how much electronics you run may be pulling to much from alternator. I would check that as well. Other than that loose, frayed or pinched wiring.

Check the switch contacts for dirt or corrosion. If you hold the switch forward and the lights remain fully bright and you let if fall to its normal high beam position, it should stay at the same power level. It may be possible that the switch is dirty or may need replacing.

Silly BUT....When you pull the highbeam back manually and hold, this is for passing and it also lights your driving lights. Release the lever and it goes back to high beams only and could explain why your lights appear dimmer??? Something to check!

What have you found?