The Park/Neutral Position (PNP) switch of the A4LD automatic transmission is responsible for engine starting in Park and Neutral positions only. It also performs additional function as Neutral safety switch. Disconnect the negative battery cable and raise the vehicle. To disconnect the harness connector from Neutral safety switch, clean the area around Neutral safety switch, and remove switch and O-ring with thin wall socket. Installation proceeds in reverse of removal; with parking brake on, the switch must operate so that in N or P the engine may start and back-up lamps may illuminate only in R. In regard to RA4A-EL and RA4AX-EL transmissions, after removing the negative battery cable and raising the vehicle, disconnect the control linkage from the transmission manual shaft, before disconnecting the park/neutral switch harness connector. Remove the switch mounting bolts and take out the switch. For installation, place the switch over the manual shaft, install the mounting bolts without tightening any of them, check that the manual shaft lever is on the L position, turn it completely rearward, return it 2 notches to the N position, insert a 0.157 inch pin through the holes of the switch and manual shaft lever, and tighten the mounting bolts to 22-35 inch lbs. After removal of pin, connect electrical connector, reinstall shift control linkage, lower vehicle, reconnect negative battery cable, and check for proper operation. For the NA4A-HL transmission, similar basic procedure to that previously described. Disconnect control linkage and wiring harness connector. Remove the switch from manual shaft lever. Place switch over manual shaft lever, install mounting bolts but do not tighten, move manual shaft lever to N position, align switch screw hole with small hole inside switch using 0.079 inch pin for alignment, tighten mounting bolts to 43-61 inch lbs., install screw in switch body, reconnect wire harness connector, reinstall control linkage, lower vehicle, reconnect negative battery cable, check for proper operation. The removal and installation processes permit adjustments to be made.