On my 90 the seat belt light stays on. i had the seats out last night and checked the circuit from the seatbelt connection thru the wire connection an up to where it goes into the center console - i unpluged the connection and shorted the circuit and still no change in the seatbelt warrning. this is not a resent problem I am just now getting to it. does anyone have experience with this peoblem or a wireing diagram with layouts of the circuit i could use to track the problem?

Not finding a seatbelt specific diagram, but I am seeing that the light in the dash is controlled by the CCM(Central Control Module), and I see an input from the air bag module to the CCM labeled "Fasten Belt output". Kinda looks like the seatbelt wiring is prolly going to the CCM, and then to the dash light. The driver side belt switch wire is black, and goes to terminal D10 on the CCM. That's as far as I have gotten. The diagrams just do not show a complete circuit, but I may be able to piece one together for you tomorrow evening. It's late, and I be sleepy!
You may have a CCM problem, OR...if someone has done any stereo work, there may be a piched or cut wire behind the stereo that goes to the CCM.
Did you check for any voltage on the wire at the belt latch?

by any chance is the infl lite on the driver information center lit. it would be in the middle of the screen. if both are on it most likely is one of your airbag sensors.  it was a problem gm had come acrossed and one solution was to take each sensor off, clean the frame and put a coat of diselectric grease in between the frame and the sensor. did one side and both lites went out on mine but came back on. haven't had time do do other side.

there are two sensors attached, one on the left, one on the right. left side you have to take out battery and tray and is right there. right side , the windshield bottle has to come out. and should be on the frame (that's the side i have not done yet).

there is a post on here and will try and find it.