I dunno if the OBS DRLs are highs on half power, or lows on half power, or something else - why I suggested measuring the voltages at the factory headlight connectors. I do know GM does some of their highs on half power in a weird manner, they run them in series when used as DRLs to drop the voltage in half. Looking at the wiring diagram for a brick Ford, OTOH, shows the DRL module connected to the lows, highs, and the high beams indicator on the dash - now the only reason I can think of why the dash indicator shoudln't be connected directly to the highs as it's done on older trucks is if at some point the high beams are lit up but not used as true high beams. And putting that together w/ what controls the dash indicator (the DRL module) it suggests to me that the module uses high beams as DRLs, but likely on reduced power. And seeing how the Ford headlights are always connected in paralled (DRLs or no DRLs), it leaves that the power reduction is done inside the DRL module itself.
Al, I made my own DRLs - I got 70-amp relays feeding full power to both the lows and the highs (not at the same time), my DRLs are my low beams w/ relay triggered by key-on power. I had to add a 3rd relay (typical 30-amp) to kill trigger signal to the low beams relay when the highs come on, but that was a very easy mod. Overall I'm very happy w/ how it turned out, I was even able to completely take the main lights switch out of headlights operation and thus vacate a spot on its connector that allows me to run dash lights only w/o the clearance markers (but when running lights are on so is the dash illumination).
