The high beam indicator is part of the actual high beam circuit. The stock high beams won't turn on if that lamp is removed and vice versa.
http://www.cygnusx1.net/Supra/Librar...x?S=Main&P=060
I suspect that in order to get the indicator working with an after market setup (whether a rewire such as recommended by Daniel Stern or a full HID kit) you'll need to set up the system to use the Red-Blue Stripe wire as ground instead of the chassis or other ground location.