Adding a remote rear hatch release to a 90-92 Firebird

The purpose of this article is to guide you through installing a remote hatch release in a 90-92 Firebird.

The remote hatch release is something so simple you wonder why GM didn’t install it on all of the cars.

First step is to locate the parts needed to do the install.

The car should already have all the necessary wiring in place. Our only concern is the components that connect to that wiring.

1. Locate and obtain an accessory switch panel with the additional mounting point for your new hatch release switch. The two-switch panel is no longer available from GM, last I checked the three switch panel was still around. Check salvage yards or Internet classifieds if you can’t find one locally.
2. Locate and obtain the rear hatch release switch. This switch runs about $45 from GM. Part number 10098572. I’d suggest trying to find one in a salvage yard or on the net first, but $45 is a small price to pay for convenience.
3. Also you’ll need a relay. The same relay is used for a horn relay on some GM cars also. The GM part number is 25523703 and it runs about $12.
4. Locate and obtain a hatch release solenoid. Currently your car will have a small latch with a cable running to the lock cylinder. You’ll need to get the solenoid from GM with a cable to that lock that will replace that assembly. My local Pontiac dealer was unable to find a part meeting that description for 91 so we looked under 87 Camaro as my Iroc used a system that was a direct interchange. The solenoid should run about $25.
5. Obtain or make a ground cable from 14 or 16ga automotive grade cable with ring terminals on each end.

Once you have the needed parts you can begin disassembling the car and installing the new parts. We’ll start at the front since its easily accessible.

1. Remove the two 7mm screws that hold the switch panel in place. They should be on the bottom side.
2. Once they’re out carefully pull the switch panel away from the dash.
3. Remove the 7mm screws from any switches currently present and remove them from the panel.
4. Locate the hatch release wiring harness. There should be three harnesses behind the panel, one for the hatch release with 4 pins, another for the rear defroster switch and the third for fog lights.
5. Remove the foam rubber padding from the harness.
6. Connect the new release switch to the harness.
7. Reinstall switches into new accessory switch panel.
8. Remove the 3 7mm screws retaining the passenger’s side under dash panel and look for a wiring harness with an orange, black, and brown wire. It should have 3 terminals and clips on each side. It may be tucked behind the bundles of wiring near the front.
9. Connect the hatch release/horn relay to this connection.
10. Reinstall the under dash panel.
11. Move to the back under the hatch. Remove the spare tire cover and the panel at the rear of the car covering the hatch pull-down assembly.
12. Locate the assembly with the cable from the lock cylinder. It should be attached with one 10mm bolt to the hatch pull-down assembly.
13. Remove the 10mm bolt and carefully pry the cable socket off the lock cylinder with a flat blade screwdriver.
14. Slip the ring terminal on the ground cable that we made earlier over the 10mm bolt.
15. Connect the solenoid cable to the lock cylinder and bolt it in place on the motor with the original 10mm bolt.
16. Connect the other end of the ground cable to the ground screw below the hatch pull down.
17. Reassemble the interior panels and test the switch.
18. When the button is pressed you should hear a pop and the hatch should open. If it doesn’t open then double-check all connections and troubleshoot for a defective component.

The process is rather simple, the hardest part is locating the parts. Any GM dealer should be able to get all the necessary parts in 3-5 business days and they can be installed in an afternoon.