GMC Sierra was launched in 1988 and is still in production today. The 1999 model year is part of the GMT800 generation, which was produced from 1998 to 2007. If you’re looking for a radio wiring diagram for a 1999 GMC Sierra, this article is for you. In this article, we’ll explain how to identify the wires and their functions, and we’ll provide a wiring diagram for your convenience.
Identifying the Wiring Harness
The wiring harness for the 1999 GMC Sierra radio is located behind the instrument panel on the driver’s side. You’ll need to remove the panel to access it. Once you’ve removed the panel, you’ll see a bundle of wires that are color-coded and labeled. There are two connectors in the bundle, one with 21 pins and one with 9 pins. The pins are numbered, so it’s easy to identify which wire goes where.
Wire Color Codes
The wire color codes for the 1999 GMC Sierra radio wiring harness are as follows:
| Wire Color | Function |
|---|---|
| Orange | 12V Switched |
| Yellow | 12V Constant |
| Black | Ground |
| Light Blue | Remote Turn-On |
| Gray | Front Right Speaker (+) |
| Gray/Black | Front Right Speaker (-) |
| White | Front Left Speaker (+) |
| White/Black | Front Left Speaker (-) |
| Purple | Rear Right Speaker (+) |
| Purple/Black | Rear Right Speaker (-) |
| Green | Rear Left Speaker (+) |
| Green/Black | Rear Left Speaker (-) |
Now that you know the color codes, let’s go over how to connect the wires to the radio.
Connecting the Wires to the Radio
If you’re installing an aftermarket radio, you’ll need to connect the wires from the wiring harness to the radio harness. To do this, you’ll need a wiring diagram for your specific radio. Refer to the diagram to determine which wire goes where.
FAQs
Q: Can I install an aftermarket radio in my 1999 GMC Sierra?
A: Yes, you can install an aftermarket radio in your 1999 GMC Sierra. You’ll need to purchase a radio harness adapter that is compatible with your vehicle’s wiring harness.
Q: Can I use the factory mounting brackets for an aftermarket radio?
A: In most cases, no. Aftermarket radios are usually a different size than the factory radio, so you’ll need to purchase a mounting kit that is compatible with your vehicle.
Q: Can I retain steering wheel controls with an aftermarket radio?
A: Yes, you can retain steering wheel controls with an aftermarket radio. You’ll need to purchase a steering wheel control adapter that is compatible with both your vehicle and your radio.
Q: Can I install a subwoofer with the factory radio?
A: Yes, you can install a subwoofer with the factory radio, but you’ll need a line output converter to convert the speaker-level outputs to RCA outputs.
In conclusion, installing a new radio in your 1999 GMC Sierra can be a simple and straightforward process if you have the right information. By following the wiring diagram and using the correct harnesses and adapters, you can have a new radio up and running in no time.
