As said most likely a earth problem for the light.
The other problem was caused by a duff alternator, the reason why the HRS switch was flashing on and off is a because it was on and the alternator charge was going on and off.
The HRS relay is energised by the output of the alternators IND terminal, the one going to your warning light, so you don't get a flat battery using HRS without engine running and charging.
Check for a GOOD earth on the alternator body, or even make a little extension up, not an uncommon problem.
tabetha