left side works fine but right side burns really dim on low and goes out when swiytching to high beams---tried a new combo switch but didn't help. Can use jumper wires straight from battery and bulb burns on high or low.

 

There's two headlight relays under the dash, up around where the steering column goes through the firewall, but the first thing I would check is your headlight ground. Find the ground wire in the headlight plug, run a jumper wire from battery negative to that wire on the plug and see if the headlight works with the switch. Also if that doesn't work, locate the headlight relays and switch them, then see if the problem moves to the other headlight. But first check your ground. Also check your headlight fuses.

 

All that has been checked. Relays are definitely good. Checked it all again yesterday to no avail. Gonna just tap the high and low beam circuit on driver side that works and use those to trigger a pair of 30 amp relays on passenger side for the high and low beams. Not unwrapping 12 feet of harness to find a corroded wire somewhere.