So, I've read through every spoiler thread I can find on reenlist and none seem to fit my symptoms (94 C2 Cab)

The spoiler light and air bag light are always on (unsure if related).
The spoiler does not automatically deploy at any speed (tested up to 85 mph...)
The spoiler works fine, both up and down, with the manual switch.
The speedometer works normally.

Based on what I've read, it could possibly be a bad speedometer circuit board, cracked solder on the clock circuit board, a bad spoiler controller, or a dirty R24 relay.

Has anyone had a similar problem or care to give troubleshooting advice?

 

Generally...if the spoiler works OK with the manual switch, but otherwise is erratic, or does not function automatically, it is the spoiler controller.

 

or his connector in the passenger footwell.

 

The connector to the spoiler controller? Good idea - I'd like to do a little troubleshooting prior to plunking down $400 for that sucker.