[blakerj10]

On my 90 blazer, when it does this- Open hood. Right next to brake booster is the wiper motor. Unplug black plastic plug. Remove he black plastic cover, it just pulls off. You can now remove the black plastic receptacle that the wiring was plug into. This is the park switch, it rides on a wheel in the motor and has two contacts like ignition points. These get a little corrosion on them and don't make good contact. Scratch them up a bit with a tiny screw driver. Pop it back together. Works perfect. Usually have to do this twice per year and it only takes 5 minutes.