My transmission will not go into park. how do i fix that

go to a service, you may have trouble parking sensor, contacts, etc.

The park pawl inside the transmission may be broken off inside the transmission. Only a repair shop can help you with that.

Does the wiper sweep past the park correct park position before parking or does it just never go low enough. If it doesn't go low enough, simply loosen the wiper arm from the transmission and lower the wiper arm to the correct park position. If it sweeps past the park position you need to disconnect the motor from the transmission when the motor is in the park position. The move the transmission to the park position and reattach it to the motor.

Shift - interlock system problem .
Automatic Transmission Shift Lock Control System
The automatic transmission shift lock control system is a safety device that prevents an inadvertent shift out of PARK when the engine is running. The driver must press the brake pedal before moving the shift lever out of PARK position. The system consists of the following components:
• The automatic transmission shift lock control solenoid
• The automatic transmission park lock solenoid
• The automatic transmission shift lock control switch
• The transmission range switch
With the ignition in the ON position, battery voltage is supplied to the automatic transmission shift lock control switch. The circuit continues through the normally-closed switch to the automatic transmission shift lock control solenoid. The transmission range switch provides a path to ground for the automatic transmission shift lock control solenoid in the PARK position. With the automatic transmission shift lock control solenoid energized the shift lever is mechanically locked in the PARK position. When the driver presses the brake pedal, the contacts in the automatic transmission shift lock control switch open, de-energizing the automatic transmission shift lock control solenoid. This allows the shift lever to move from the PARK position. When the shift lever is out of the PARK position the controlled ground contacts in the transmission range switch open. This prevents the automatic transmission shift lock solenoid from energizing when the vehicle is out of the PARK position.

Park Position Switch? If you are refering to the Transmission Range (TR) sensor, it is located on the lower driver's side front of the transmission housing.

What is it you are trying to fix?

I suspect that there is a simple fix.
Under the car.... at the point where the shift lever rod connects to the transmission shift lever(s)...... loosen the nut on the Park transmission shift lever... and place the lever all the way into the park position.... You can confirm by attempting to start the car....
Once you are sure that it is in "Park", you can tighten the shift lever nut....

down at the transmission is an adjustment you can make to hopefully get it bak to park on the left side of the transmission you will find a cable with a nut at the end loosen the nut and move the lever on tranny until it locks into park. if it doesn't work get help from a tranny shop too complicated. and a major job to replace park pin

sounds like the transmission linkage is out of adjustment,loosen the bolt that connects the linkage to the transmission,put the lever in the car in park and move the linkage on the transmission to park, tighten bolt,try that if you needmore help get back to me Thanks Ray

Have someone operate the gear shift while you watch the mechanism on the transmission so that you know what parts you are looking for. Shift into the park position, then uncouple the linkage and move the lever on the transmission fully into the park position. Then adjust the length of the linkage while holding the driver's lever in the park position so that the linkage connector goes back together without pulling on anything.

Inside the transmission is a brake lever which locks onto the band when shifted in to park. The lever must have a broken spring attached to it. It is internal so expensive to fix