Trunk problem when i put my 97 grand prix in reverse the trunk pops open,any help on this problem

Is this an aftermarket key opener. ? The brain box for this unit is some times mounted behind the left kicker panel by the left foot of the driver. And they get wet from foot water ie snow. Rain. The yr of ur car sounds like this unit could be water damaged. Have a look. Is u see green stuff allover the contracts thats ur issue. As well some times older cars remote fob controller is not isolated from other sigs. Ur truck does it only pop open when parked in one location ie home or work u might be picking up a similar radio req as ur button for truck lid as they have different radio freqs to control different things

Go to page 97 0f the owner's manual at the link to the manual below. https://my.gm.com/content/dam/gmownercenter/gmna/dynamic/manuals/2007/pontiac/grand_prix/2007_pontiac_grand_prix_owners.pdf

Your reverse light wires are probably
rubbed thru and touching the wire
that activates the trunk release. remove
the reverse light bulbs and see if it does it again, or remove the fuse for the trunk release. Also have someone look at the
reverse lights while your pushing
the trunk button on the drivers door.
If yhey come on then you know the circuit
is shorting to power

You have a short between the trunk motor and the reverse lights. Follow the harness from the trunk latch to to reverse lights. Open the harness there and start looking.

Try going between the glass with a piece of wire and hook the rod where the key rod is because the buttons are inside the car on top of the seat

The door unlock switch. Press toward unlock and hold until trunk pops.

Sounds like your transmission is slipping or your torque converter is bad.---check the transmission fluid level and see if it smells burnt and discolored.

These cars have a body control module which could be faulty,have a mechanic check this out.

wiring shortage. take it to the good electician mechanic.

Did you check to see if you're getting power at the bulb socket