The high-beam indicator bulb is negative-switched meaning the bulb should always have power anytime the headlight switch is turned on. However, in order for the high-beam indicator bulb to actually illuminate it must see a ground connection through the high-beam selector in the stalk switch.

Power for the high-beam indicator bulb comes from dedicated fuse #7 (10A) and should be under the hood.

It is very difficult to work on the cluster itself since you can't get to the rear circuits when it is plugged in to test with a VOM. With the cluster removed you want to find connector C-05. PIN 30 should show 12-volts when the headlight switch is on. Pin #21 should show ground only when the high-beam switch is on.

http://nawdu.de/files/97-99Electrical.PDF
Pages 168 and 169