I am looking for some help. The driverside headlight switches from low beam to high beam and high beam to low beam with no problem. the passenger side only works on high beam. I have check the wiring and change headlights. can't seem to find the problem, does anyone have any suggestions or ideas as to what It could be.

Thanks

oh by the way.It is a 71 chevelle. sorry I didn't mention it.

These issues are usually due to bad connections. If you already tried swapping lights from one side to the other and the bad one works on the other side then you have a bad connection on the low side of bulb on the passenger side. Switch to low and check the voltage on the low side on your passenger bulb and I bet it'll read very low or nothing. If this is the case then trace out the wire and find the connection issue.

Or, the wire end in the connector could be pushed back so it doesn't make connection.