Chevy & GMC Vans

Hey guys - 2000 Astro RWD - No headlights, no brights. Checked power to bulbs, no ground. Used scotch lock on one headlight ground (yellow) wire and grounded direct to frame. Now all 4 lights come on. pull turn signal to switch brights and nothing happens. All 4 lights stay on. No hi-beam display light on dash either. Maybe dimmer switch is bad? Where do all those little yellow ground wires connect to?

Total guess here, but consider the DRL module or fuse for that if applicable. Hopefully someone else will chime in....

The only yellow wires to the headlights are the power input on the left headlamp. These yellow wires come from the HEADLAMP fuse LH in the underhood fuse block. The ground for the lights comes from thru the dark blue for the low beam & the pink wire for the high beam. This ground circuit is controlled via the DRL relay & the healight dimmer switch.

I didn't know ground circuits existed until I talked to a fleet mechanic friend of mine, who is hopefully getting me a new multifunction switch. The DRL relay seems to be working properly, but should I try replacing that first before the multi switch? (I would have to disconnect my new ground first before trying it out)