Not sure whats happening here, dont recall people complaining about this issue, guess its the switch, hope its not the wiring harness

high beams are on through the flash to pass even when car is off

 

S4 or S5?

 

s4 convertible

 

Your Dimmer Switch has the ability to send a ground signal to the Headlight Relay which then sends voltage to the Dimmer Relay which then decides whether to power the low beams or the high beams. In your case chances are your Dimmer Switch is probably at fault here because this switch also sends a ground signal to the Dimmer Relay so it can switch from low beams to high beams. So, you have two wires coming from this switch which have grounds currently on them at the same time thus this likely places the cause on the switch itself and not the wiring harness. If you could depin the Red/White wire from the Dimmer Switch plug and this causes the flash to pass lights to turn off then you would know that your problem exists in the switch.

 

Thanks, you are like an Fc electrcial guru, ill try it tomorrow.
My dimmer switch was acting up years ago but dont recall it lately. My dash lights would dim and i would just tap the switch a little bit and it would be fine. Happened once in a while but not in a long time. Is that switch rebuildable?

 

I wouldn't know. Seems like the latching lever is the source of your problem for it appears it is stuck in one position when it should not (stuck in the pulled back setting). And one who read HAILERS' posts, for example, would get the same info that I shared w/you.