Gmc  Full Size Pickup (Old Body Style) 1999-2000
 PART   COLOR  LOCATION
 12 VOLT CONSTANT   RED (+)   @ IGNITION SWITCH HARNESS
 STARTER  YELLOW (+) or PURPLE (+)  @ IGNITION SWITCH HARNESS
 STARTER 2  N/A  
 IGNITION 1  PINK (+)  @ IGNITION SWITCH HARNESS
 IGNITION 2  WHITE (+), See NOTE #7  @ IGNITION SWITCH HARNESS
 IGNITION 3  N/A  
 ACCESSORY/HEATER BLOWER 1  ORANGE (+)  @ IGNITION SWITCH HARNESS
 ACCESSORY/HEATER BLOWER 2  N/A  
 KEYSENSE  N/A  
 PARKING LIGHTS ( - )  N/A  
 PARKING LIGHTS ( + )  BROWN (+)  @ HEADLIGHT SWITCH or FUSE PANEL
 POWER LOCK  LIGHT BLUE (TYPE C), See NOTE #2  IN EITHER DOOR BOOT
 POWER UNLOCK  WHITE (TYPE C), See NOTE #2  IN EITHER DOOR BOOT
 DOOR TRIGGER  See NOTE #3  @ BCM, BEHIND the DRIVERS SIDE of DASH
 DOMELIGHT SUPERVISION  TAN (-)  @ BCM, BEHIND dirvers SIDE OF dash
 TRUNK RELEASE  N/A  
 SLIDING POWER DOOR  N/A  
 HORN  BLACK (-)  @ STEERING COLUMN HARNESS
 TACH  WHITE (AC) , See NOTE #5  @ ECM, See NOTE #4
 WAIT TO START LIGHT  DARK BLUE (-), See NOTE #6  @ INSTRUMENT CLUSTER
 BRAKE  WHITE (+)  @ SWITCH ABOVE BRAKE PEDAL
 FACTORY ALARM DISARM   N/A  
 ANTI-THEFT  YELLOW (+), ORANGE/BLACK (-) and RED/WHITE (Not used)  GM's PASSLOCK 2 System, these wires exit the Ignition Switch Tumbler together and are in the Main Ignition Switch Harness in the Column.
 EXTRA INFORMATION
 NOTE #1: This vehicle uses GM'S PASSLOCK 2 ANTI-THEFT SYSTEM that requires a 791 Bypass Module to Remote Start, to order go to the SECURITY BYPASS MODULES Page on this website. NOTE #2: if vehicle is a 2-Door it is a TYPE C door lock system, if vehicle is a 4-Door or if it has a FACTORY KEYLESS ENTRY System it is a TYPE A door lock system. NOTE #3: At the BCM the DRIVER DOOR is a TAN (-) Pin B4 of the PURPLE PLUG, the PASSENGER DOOR is a ORANGE (-) Pin B2. When connecting to an alarm system use both wires and DIODE ISOLATE. See DIAGRAM NOTE #4; the ECM is located on the DRIVERS SIDE inner fender, with 2 plugs, look for the WHITE wire in the plug labled "WHITE" NOTE #5: THE DIESEL TACH wire is also a WHITE but at the Instrument cluster. NOTE #6; when hooking up a remote starter, if you cannot get the (+) or (-) Wait to Start wire on the Remote Starter to work properly, you will then need to disconnect this wire and Program the Remote Starter for the 5, 10, 15 or 20 Second Wait to Start Timmer in the Installation manual. NOTE #7; IMPORTANT !!!!! this wire MUST BE CONNECTED as IGNITION #2 for REMOTE STARTING!!!!!!