<VV> Headlights

[Ron]

I've been having problems with the headlights kicking off in a random fashion when on high beam.  A light switch or two burned out (circuit breaker) before I switched to relays but now the high beam breaker (an add on) kicked off when on high beam last evening and when it went off, both sets of lights went out.  So, my question is, where is the connection from the high beam circuit to the low beam circuit?  Since there is this connection, why don't the highs go on when the lows are energized since this connection must be after the dimmer switch.?  How does this work?

RonH