Check here on bulbs: http://gdl-online.com/bulb.html
The problem is on the reset circuit from ground(pin #8 on CC amp.); I'm not clever enough to figure out the circuit, but bulbs will NOT do it most likely (see above link). Several folks, including me, have posted the same dilemma with no resolution except getting a rebuilt amp. from GDL. I'd check and clean the stop light microswitch at the brake pedal. Some folks resolder the amp. circuit board, hoping to correct a cold solder joint. As always capacitors are suspect and 15 year old chips don't build confidence either.

If some EE type knows what a simple reset circuit looks like, I'll try some selective component replacement on my amp.

Please post outcome on your solution (hopefully).

__________________
The Golden Rule

1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)