I have a 1989 Gas Barth that was a bookmobile. EWhen I turn on the driving lights the guages on the dash go weird and when I hit the brights they all 4 get dim. Any hints?

From my Barthmobile education I'm going to say it could be a ground problem.

I agree with Danny; on most Barths there are multiple grounding bars. There should be one in the dash.

Bad contacts or connection on light switch. Do a search for relay upgrade. When you get to connector on light switch I bet you find it melted.

That's a distinct possibility also. I left one morning before daybreak, and smelled some burning in the dash; the connector to the headlight switch had melted. I parked until daylight. The switch and connector were available at NAPA - over $100 for both. The headlight relays went in shortly after...

This and other posts on headlight relay ( rusty's excellent 'how to do it ' posts along with bill's drawing ) had me decide to do the relay deal... To my surprise, the previous owner had this already done... Relay was added in the electrical bay ( 12volt bus bars with circuit breakers were labeled... One said high beams... A wire came off the breaker to a relay mounted on floor of bin... Fat wires on relay... Wires and plugs on back of headlights looked newish...thanks for the post.. Got me thinking and looking... Thanks rusty... You got me off the couch...