The headlight delay relay was optional on Chargers still with hideaways.
Now, where it mounts, dunno. I know the hideaways relay fits on dash frame around the headlights switch

Since hideaways are feeded from the RUN circuit, I guess when time delay is activated by the correct sequence, doors will remain open still after turn off the headlights and will close the doors as soon you set ign switch back on RUN next time you try to start up the engine