87 Firebird GTA
pulldown motor works but I am having issues with the in cabin hatch release button: when pressed the hatch doesnt pop but BRAKE light comes on the cluster. When parking brake is set the light doesn't come on but nothing happens.

I have:
jumped the plug at the latch - it pops
checked fuses
checked connection at parking brake
I think I found the relay - under the dash on a tray with a few other fuses/relays - if that is the relay then i replaced it and it's not the issue
any grounds i see look good

obviously there's a break in connection somewhere but short of yanking up the carpet and checking all of the wiring what else can I look for?

 

OK, so there are different set ups from year to year, and from auto the manual cars. I don't know for sure exactly how your car is set up, but I'm guessing it's a manual? I think for manual cars (mine is originally an automatic) the hatch won't pop unless the parking brake is applied. ....since you're trying to pop the hatch and that BRAKE light comes on, that tells me something under the console is wired backwards. Perhaps a hack/fix at some point?

MY switch on my 89 has 3 wires where the pigtail connects right under the switch, at the console. A constant 12v power, a ground(for me the car had to be in park/neutral) and a wire to deliver power to the back of the car. ...once you get past that 3 wire pigtail, you should have a relay and the switch itself. Yours may be different, but I'd still start in the same place.

Get your Multimeter, get inside the console and MM the heck out of every wire attached to that switch and the e brake cable. See if you can locate ground, constant power, the wire that ultimately runs to the hatch solenoid out back, and also check that parking brake wire. Once you see what you have, where and when you have voltage, you can probably piece together what's going on.

 

I don't want to lead you TOO far down my path in the event 89 is different from 87, but here's how mine worked.

Constant 12v powered the relay.
Ground from the shifter to the switch when in park/neutral.
Power FROM the switch tripped the relay...and sent power to the solenoid.

 

Thank you!!! I will look into this and report back.
car is auto btw

 

Does the BRAKE light on the dash come on with the actual parking brake? Those switches operate via connecting a ground. Parking brake level grounds the BRAKE light circuit. ....so if the hatch switch is turning on the BRAKE light....

LOL....time to play detective.

 

Okay so I have power to the black/white wire and no power anywhere else, regardless if the brake is up or down or if the switch is being pressed.

 

BRAKE light does not come on when parking brake is up.
I think switch is good because I think I am hearing the relay clicking when I press it. But still nothing happens.

 

Try taking the ground from the hatch switch and running it to the brake lever. See if that turns the light on. ....if so, at least you've solved ONE issue, lol.

Do you have a shift lever switch with the wiring??? Do you have a yellow wire on that switch? ...again keep in mind that colors and relay locations are different, so don't just randomly start hooking stuff up!!!

....on MY car....the shifter grounds the hatch switch in park and neutral via a yellow wire.

 

This is from the 88 Firebird Service Manual,... pretty sure the wiring lay-out is exactly the same as your 87 Firebird.

Hatch:


Brake Warning: Diagram


Brake Warning: Symptoms




That should help you find the bug !!