There's alot of different things that you need to know about the Montana. Here is a detailed wiring diagram for the 2003 Pontiac: Use the tech notes on the botton to help you witht he installation:
| ITEM | WIRE COLOR |POL| WIRE LOCATION |
| 12V|red & RED / white |+ |ignition harness |
| STARTER|yellow |+ |ignition harness |
| IGNITION|pink |+ |ignition harness |
| SECOND IGNITION|white |+ |ignition harness |
| ACCESSORY|orange |+ |ignition harness |
| POWER LOCK|RED / black *3 |- |BCM, to right of glove box |
| POWER UNLOCK|ORANGE / black *3 |- |BCM, to right of glove box |
| LOCK MOTOR|gray | |BCM, to right of glove box |
| UNLOCK MOTOR|tan | |BCM, to right of glove box |
| DISARM DEFEAT|tan | |BCM, to right of glove box |
| PARKING LIGHTS +|brown | |drivers kick or light switch|
| PARKING LIGHTS -|BROWN / white | |BCM, to right of glove box |
| HEADLIGHTS|yellow |+ |headlight switch |
| DOOR TRIGGER|gray/black *1 |- |BCM, to right of glove box |
| DOME SUPERVISION|use door trigger | | |
| TRUNK/HATCH PIN|tied in with doors | | |
|TRNK/HTCH RELEASE|*6 |- |*6 |
| FCTRY ALARM ARM|arms w/ lock | | |
|FCTRY ALRM DISARM|disarms w/ unlock | | |
| DISARM NO UNLOCK|*4 | | |
| TACHOMETER|PURPLE / white | |ign coils or PCM *5 |
| SPEED SENSE|green | |BCM, to right of glove box |
| BRAKE WIRE|white |+ |brake switch |
| HORN TRIGGER|black |- |BCM, to right of glove box |
| WIPERS|purple *2 |+ |wiper motor |
| LF WINDOW UP/DN|blue - brown |A |drivers window switch |
| RF WINDOW UP/DN|lt. blu - tan |A |drivers door harness |
| LR WINDOW UP/DN|not recommended | | |
| RR WINDOW UP/DN|not recommended | | |
| RADIO 12V|orange | |radio |
| RADIO GROUND|BLACK/ white | |radio |
| RADIO SWITCH|yellow | |radio |
| RADIO ILLUMINATE|gray/black | |radio |
| LF SPEAKER|tan - gray | |radio |
| RF SPEAKER|lt. grn - green | |radio |
| LR SPEAKER|brown - yellow | |radio |
| RR SPEAKER|blue - lt. blu | |radio |
Notes:
NOTE: This vehicle is equipped with the pass-key III immobilizer. Use PKG4 or PKG5 are recommended bypass modules for bypassing the Pass-Key III *1 To avoid the domelight delay use tan for the drivers door, blue for the passenger door and the liftgate, and orange for the sliding doors. All wires are negative trigger, located at the BCM and all need to be diode isolated from eachother. *2 This wire is only activated when the wipers are in the high/fast position. There is not a wire for the low setting. *3 The door lock wires will only meter when turning the key in either door key cylinder. Also have to program the door lock pulse duration for 3.5 seconds to unlock the doors. On vehicles without the factory alarm, use lt. blue for lock and white for unlock. Find the wires in either kick panel. *4 To disarm the factory alarm without unlocking the doors, use a 0.8 second pulse on the unlock wire. *5 The ignition coil pack is on the top of the engine on the passenger side. The PCM is in the air cleaner assembly on the front of the engine compartment on the driver side, the wire is in the blue plug in pin 8. *6 The driver side power sliding door is lt. blue/black (-) in the driver kick panel in the harness going to the rear. The passenger side power sliding door is lt. blue (-) in the passenger kick panel in the harness going to the rear.
Jeff
Velocity Custom Home Theater
Mobile Audio/Video Specialist
Morden, Manitoba CANADA