Question: Where can I find a 1991 GMC Sierra 1500 radio wiring diagram? What are the 1991 GMC Sierra 1500 radio wiring harness color codes?
If you’re planning to upgrade the radio in your 1991 GMC Sierra 1500 or troubleshoot issues with your car stereo, this guide is here to help!
Our comprehensive 1991 GMC Sierra 1500 radio wiring diagram shows all the radio wire harness colors, speaker wire colors, and speaker sizes. Use this head unit pinout guide to help with your car stereo installation or to troubleshoot radio wiring issues in your 1991 GMC Sierra 1500.
In This Guide
1991 GMC Sierra 1500 Car Stereo Wiring Diagram
This 1991 GMC Sierra 1500 radio wiring chart shows you all the 1991 GMC Sierra 1500 stereo wire color codes and their radio wire functions. This easy-to-follow guide can help you install a new car stereo or figure out problems with your stereo wiring harness and radio setup. If you don’t see the car radio wiring information you’re looking for, please feel free to ask your question at the bottom of this page.
| Car Stereo Wire Function | Wire Color Code |
|---|---|
| Battery Constant Power Wire (12v+) | Orange |
| Accessory Switched Power Wire (12v+) | Yellow |
| Ground Wire | Black/White |
Use a Wiring Harness  and Dash Kit  for an Easy Install! |
|
| Illumination Wire | Brown |
| Dimmer Wire | Gray |
| Antenna Trigger Wire | N/A |
| Amplifier Turn-On Wire | N/A |
| Amplifier Mute Wire | N/A |
| Amplifier Location | Under the center console. |
1991 GMC Sierra 1500 Speaker Wiring Guide
This 1991 GMC Sierra 1500 speaker wiring guide provides all the speaker wire colors and speaker locations you need for an upgrade or replacement. Whether you are installing new speakers or troubleshooting your factory setup, this 1991 GMC Sierra 1500 chart makes it easy to identify each wire and where it connects. If you don’t see the car speaker wiring info you need, feel free to ask your question at the bottom of the page — we are here to help!
| Car Stereo Wire Function | Wire Color Code |
|---|---|
| Dash Center Speaker Positive Wire (+) | N/A |
| Dash Center Speaker Negative Wire (-) | N/A |
| Front Left Tweeter Positive Wire (+) | N/A |
| Front Left Tweeter Negative Wire (-) | N/A |
| Front Right Tweeter Positive Wire (+) | N/A |
| Front Right Tweeter Negative Wire (-) | N/A |
| Front Left Speaker Positive Wire (+) | Tan |
| Front Left Speaker Negative Wire (-) | Gray |
| Front Right Speaker Positive Wire (+) | Light Green |
| Front Right Speaker Negative Wire (-) | Dark Green |
| Rear Left Tweeter Positive Wire (+) | N/A |
| Rear Left Tweeter Negative Wire (-) | N/A |
| Rear Right Tweeter Positive Wire (+) | N/A |
| Rear Right Tweeter Negative Wire (-) | N/A |
| Rear Left Speaker Positive Wire (+) | Brown |
| Rear Left Speaker Negative Wire (-) | Yellow |
| Rear Right Speaker Positive Wire (+) | Dark Blue |
| Rear Right Speaker Negative Wire (-) | Light Blue |
| Left Subwoofer Positive Wire (+) | N/A |
| Left Subwoofer Negative Wire (-) | N/A |
| Right Subwoofer Positive Wire (+) | N/A |
| Right Subwoofer Negative Wire (-) | N/A |
1991 GMC Sierra 1500 Speaker Sizes and Locations
This 1991 GMC Sierra 1500 speaker guide includes speaker sizes, speaker locations, and helpful info on speaker upgrades. Use this chart to find out what size speakers fit your 1991 GMC Sierra 1500.
| Application | Speaker Size/Location |
|---|---|
| Dash Center Speaker Size | N/A |
| Dash Center Speaker Depth | N/A |
| Dash Center Speaker Location | N/A |
| Front Tweeter Size | N/A |
| Front Tweeter Depth | N/A |
| Front Tweeter Location | N/A |
| Front Speaker Size | 4″ x 6″ Speakers |
| Front Speaker Depth | 2.5″ Depth |
| Front Speaker Location | Front Doors |
| Rear Tweeter Size | N/A |
| Rear Tweeter Depth | N/A |
| Rear Tweeter Location | N/A |
| Rear Speaker Size | 4″ x 6″ Speakers |
| Rear Speaker Depth | 4″ Depth |
| Rear Speaker Location | N/A |
| Subwoofer Size | N/A |
| Subwoofer Depth | N/A |
| Subwoofer Location | N/A |
Questions and Answers
If you have any questions about your 1991 GMC Sierra 1500 radio installation, please don’t hesitate to post them at the bottom of this page. We’re committed to finding the answers you need, and members of the Modified Life community may also provide valuable insights into the car stereo information you’re looking for. Don’t hesitate to ask your car audio question; it could benefit others seeking the same answers!
Contribute
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4 thoughts on “1991 GMC Sierra 1500 Stereo Wiring Diagram”
where do you put the new deck? in place of the cassette deck or in place of the radio? and where do you get plates for these? Thanks
Brady, when installing an aftermarket radio in your 1991 GMC Sierra C1500, the new deck is usually installed in place of the radio. Here is the dash kit you need:
Stereo Dash Kit for 1991 GMC Sierra C1500
If you’ve never installed car audio before, we advise you to take your car to an experienced mobile audio installer. Hope this helps. Good luck with your 1991 GMC Sierra C1500 stereo installation.
Easy as pie! I love your web site……… I have a 1991 gmc sierra that I bought from a buddy that was just a rolling chasis. I’ve been in and out of it with ur help…. thanks again
Scott, we are happy we could help you with your 1991 GMC Sierra stereo wiring diagram needs.