88 gmc pickup door locks

Printed From: the12volt.com
Forum Name: Car Security and Convenience
Forum Discription: Car Alarms, Keyless Entries, Remote Starters, Immobilizer Bypasses, Sensors, Door Locks, Window Modules, Heated Mirrors, Heated Seats, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=25361
Printed Date: July 20, 2025 at 4:38 PM

Topic: 88 gmc pickup door locks

Posted By: kwhite
Subject: 88 gmc pickup door locks
Date Posted: January 27, 2004 at 1:51 PM

please help... I have a remote starter installed and it works fine, but I am trying to get the keyless lock/unlock to work. The locks have a 5 wire switch but when I hook up everything like the diagram says using 30 amp relays, it won't work. the truck is waiting in the garage and my wife is mad cause she parks her car in there and it's snowing. Help Please...

Replies:

Posted By: boomer_106
Date Posted: January 27, 2004 at 2:41 PM

Did you doublecheck the wiring? Below is what I have on that truck. Try checking the output of the relays with your meter when you operate the switch and see if it changes state.

GMC

Sierra Pickup

1988-1991

Remote Starter Wiring Colors and Notes
Function	Vehicle Color	Location
Start:	PURPLE OR YELLOW	IGNITION SWITCH HARNESS *
Ignition #1:	PINK	IGNITION SWITCH HARNESS
Ignition #2:	ORANGE	IGNITION SWITCH HARNESS (HEAT-A/C)
Ignition #3:	N/A
Accessory:	BROWN	IGNITION SWITCH HARNESS (RADIO/WIPER)
Brake Light:	WHITE	AT SWITCH ON BRAKE PEDAL BRACKET
Tach Signal:	WHITE	AT DISTRIBUTOR OR IGNITION COIL
Parking Lights:	BROWN	(+) AT LIGHT SWITCH
Headlights:	YELLOW (+)	HEADLIGHT SWITCH OR BEAM SELECT SW.
OEM Alarm Disarm:	N/A
OEM Alarm Arm:	N/A
Diesel Glow Plug:
Clutch Bypass Wire:
Notes:	* See Note #300 - GM Rear Wheel Drive Vehicles

GMC

Sierra Pickup

1988-1991

Alarm and Keyless Entry Wiring Colors and Notes
Function	Vehicle Color	Location
Constant +12 Volts:	RED AND RED	IGNITION SWITCH HARNESS
Starter Kill:	PURPLE OR YELLOW	IGNITION SWITCH HARNESS *
Ignition +12 Volts:	PINK	IGNITION SWITCH HARNESS
Dome Lights/Superv:	WHITE	(-) PIN SWITCH OR AT COURTESY LIGHT
OEM Horn:	BLACK (-)	STEERING COLUMN HARNESS OR AT RELAY
Power Lock:	L BLUE	DRIVER'S KICK OR BELOW SPEAKER **
Power Unlock:	BLACK/ WHITE	DRIVER'S KICK OR BELOW SPEAKER **
Trunk Release:	N/A
Alarm Input Wire:	WHITE	(-) PIN SWITCH OR AT COURTESY LIGHT
Notes:	** See Note #203 - Reverse Polarity Door Lock Diagram.

Posted By: kwhite
Date Posted: January 27, 2004 at 2:49 PM

the remote starter has this - green=lock light blue=unlock . it also says it is for a negative door lock system. will it not work for me? do i have to wire it some weird way that isn't in one of the diagrams?

Posted By: boomer_106
Date Posted: January 27, 2004 at 2:57 PM

It is a reverse polarity doorlock system. The colors and connection location are what I have listed above. The following link will show you exactly how to wire it. Follow it closely and doublecheck as you go and you should be in business and the wife will be happy. posted_image

Posted By: boomer_106
Date Posted: January 27, 2004 at 2:58 PM

I guess I should remember to include the link. Sorry about that.

https://www.designtech-intl.com/Content/techsupport/documents/section04/note203.pdf

Posted By: kwhite
Date Posted: January 27, 2004 at 3:04 PM

thank you, thank you, thank you.

Posted By: boomer_106
Date Posted: January 27, 2004 at 3:08 PM

Your Welcome