I am having a similar problem with my shift control bulb on my 92. I have the normal shift and the performance shift. The performance shift works just fine but the normal shift only works sometimes. Only when it is very very cold out and then after a bit it starts to flash like it is sending out codes. This has really kind of messed me up because here I am trying to take down the morse code that is coming out but it is too fast. I soon realized that it is not a flashing code (dumbass). So what you are saying is that it is a problem in the cirsuit board or the bulb (led)itself?
It would be nice to know what this is so when I get a bit of free time I can fix.
1992 Bonneville SSEi
White, grey Leather interior.
Tinted windows and blackouts on headlights.
Custom high flow exhaust, Everything replaceable - DONE
300 000 kms original engine, tranny 2 rebuilds.
Playboy Bunnies Embossed in Tint. Oh Yah!
Ever Seen a Polar Bear in a Snow Storm?