ATTENTION: All Postings that advertise items for sale will be deleted from the Discussion Forum. You may post sale items for free in the Classifieds section. Sign up now.
Your unit is old and the starter expensive., SO we need to ensure the stater is getting voltage when you push the button. I know access is dificult but you need to measure voltage @ the starter battery cable conection and try to start it. if it stays over 18 volts it should probably work. Then tear it apart and probably replace the solinoid. If you go to a rebuilt or new stater (recomended) make sure you get the correct rotation. Most GM busses rotate the stater backwards as well as the engine at least in relation to the rest of the world. Voltage supply to the solinoid could also cause this. Same test just to the terminal the button activates. There is probably a relay that triggers this and they go bad too. Good Luck