aftermarket alarm install in a 1999 grand prix gt 4dr

**1999GrandPrix** · 01-15-2012

hey room, getting ready to install an aftermarket alarm with remote start in my 99 grand prix gt. question is... do i need to add relays for the power door locks? if im correct both should rest at negative polarity when at rest. iv tried to research it and seen where some people say u need a relay and some people say you dont?? which is it. iv installed alarms before and enjoy doing it. relays are just my weakness lol... lemme know your experiences with installing aftermarket alarms?? are grand prix pretty much straight forward? already found out that i did not need any kind of ignition bypass vats or passlock so im happy bout that. apparently 2000 and newer gp required them...

**KeithGTP03** · 01-15-2012

No relays needed. Its a light blue wire in the driver side kick panel that will show -. You will need a multimeter cuz they packed a bunch of light blue wires in there. You said you've installed alarms before, so this should be familiar. But if not, just set the multimeter to continuity..attach one lead to a chassis ground and the other lead to the wire you suspect. The meter should read 0...or if your multimeter has audible signal, it should have a constant tone. Hit the lock and if the tone goes away or jumps from 0, you found the wire. Here is a wire color code if you dont already have it 1999 Pontiac Grand Prix Alarm, Remote Starter, Keyless Entry Wiring Information ..The door triggers are supposed to be diode isolated, but I didnt need to isolate mine. You will need a relay to pop the trunk though.

**1999GrandPrix** · 01-15-2012

Thanks keith, to pop the trunk, im sure its a neg trigger so what does the wiring look like on the relay?

**Compg4me** · 01-15-2012

Pin 85 on the relay should be the negative trunk release out put from the remote start, pin 86 would be 12 volt, pin 30 would also be 12 volt and pin 87 would go out to the trunk release wire in the car. 87a isn't used for trunk release. Hope this helps.

**1999GrandPrix** · 01-15-2012

so pin 86 and 12 would tie together to a 12 volt source? pin 85 would tie into the aftermarket alarm trunk release? and pin 87 would go into the trunk release wire itself?

**Compg4me** · 01-15-2012

86 and 30 to 12 volts 85 from remote start negative trunk release 87 to trunk release in glove box

**1999GrandPrix** · 01-15-2012

this is what the wiring info says. is this still how i wire up the relay? kind of confusing lol

Trunk Release

Black/White (+)

Switch or Brown (-) at Keyless Module

**1999GrandPrix** · 01-15-2012

lol alarm itself says trunk release negative.. now on the chart that i posted above, does it look like a neg trigger on the trunk release? or do i just add the relay as described by comp?

**KeithGTP03** · 01-16-2012

Almost as comp said....85 to alarms trunk output (usually the red/white). Jump 86 and 87 with a constant 12v. And then 30 to the cars trunk release....you can disassemble the glove box and get it at the switch. I found mine behind the radio, I cant remember which wire though. I just looked for a 12v once the trunk release button in the glove box was pushed. And I believe it was, in fact, black/white. If you go with a negative trigger, you will need to ground 87 instead of powering it.

**apierce1289** · 09-18-2012

Originally Posted by KeithGTP03

Almost as comp said....85 to alarms trunk output (usually the red/white). Jump 86 and 87 with a constant 12v. And then 30 to the cars trunk release....you can disassemble the glove box and get it at the switch. I found mine behind the radio, I cant remember which wire though. I just looked for a 12v once the trunk release button in the glove box was pushed. And I believe it was, in fact, black/white. If you go with a negative trigger, you will need to ground 87 instead of powering it.

I'm so confused now I was told to tie 86 into 30. Then 85 to the negative trunk output on my Viper Alarm, then 87 goes to the positive trunk release on the car?

The positive trigger would be 87----->Black/White wouldn't it?

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**apierce1289** · 09-18-2012

Forgot to add that I have a 2002 grand prix 4dr but it should be the same I would think?

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**KeithGTP03** · 09-19-2012

Originally Posted by apierce1289

I'm so confused now I was told to tie 86 into 30. Then 85 to the negative trunk output on my Viper Alarm, then 87 goes to the positive trunk release on the car?

The positive trigger would be 87----->Black/White wouldn't it?

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Sorry for the confusion. Yes, just like that. I went to the switch in the glove box, and IIRC it was black/white. I just tested for the wire that jumped to 12v once the button was pushed.

**BillBoost37** · 09-21-2012

The reason you see it differently Alex is..there are two ways to do it. Notice the + or - signs on the other post. Depending on where you tie in..makes up the ...which you need. I tied into the remote function with the neg off the alarm and didn't have to use a relay to flip - to +. That is what is happening with that relay in the picture.

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