I just developed the same problem on my 90. The INFL REST light came on and my seat belt light on my dash stays on when my seat belt is engaged. I haven't messed with it yet, but if it is a simple plug check I am in. Can you tell me where exactly the yellow wires are? The driver or passenger side and if I need to remove anything to get to them?
Thanks for the input, I had some real issues with this baby initially and got some great advice and parts from this site, especially from Jeff.