dummy lights on/tranny shifting

I have a 92 aerostar 3.0L. with 130K miles. The door ajar light is always on the brake and rear abs light go on and off at times (maybe when I turn or hit bumps). The air bag light is constantly flashing. Also the tranny shifts erratically when on the highway going up hill. Are these problems related? Where should I start in fixing them? Any help apreciated. Thanks, Feld.

Welcome to AF! Have you cleaned and tightened the battery terminals and the grounds? Lights coming on with no rhyme or reason indicate a low voltage in the system. Have your battery tested. Count the number of flashes on the air bag warning. It will flash 2 numbers in sequence then pause. This is the code. However, it is unusual that all these lights are occuring at the same time. How 'bout some more input out there? Two opinions are better than one.