Common Dash Cam Wiring Issues for
GM Vehicles

The first fundamental issue pertains mostly to older GM vehicle models, where the cigarette socket ports stay on when the vehicle is off. Cigarette lighter ports that stay on when the vehicle is off are unusable for powering a battery pack or a dash cam, as there’s nothing to prevent them from fully draining your 12V or 24V vehicle battery. If this sounds like your GM vehicle, we firmly do not recommend connecting a cigarette lighter adapter for either a dash cam or battery pack.

The second issue applicable to battery pack hardwiring installation, specifically, is the lack of a sufficiently powerful ACC (Accessory) in newer full-sized trucks and SUVs on the GMT T1XX platform.

This is a problem, as battery packs should ideally be wired into a 20A-30A accessory fuse that can handle the high current of a battery (9A max, depending on battery model). An ACC connection is required as it ensures that the battery will only charge when the vehicle is running, supplying that power when the vehicle is turned off. While most vehicles use one of these fuse types for their 20A-30A accessory circuits, the only suitable ACC circuit we’ve found in these vehicles uses an unconventional 50A JCase fuse.

Affected GMT T1XX vehicles include but are not limited to:

• Cadillac: Escalade and Escalade ESV (2021+)
• Chevrolet: Silverado 1500 (2019+), Silverado HD (2020+), Suburban and Tahoe (2021+)
• GMC: Sierra 1500 (2019+), Sierra HD (2020+), Yukon and Yukon XL (2021+)

Lastly, GM fuse boxes themselves also have plenty of traps that are not ideal to wire to, even if yours are all standard fuses. These are RAP fuses, aka delayed ACC fuses, and you may have previously encountered these if you’ve worked with the fuse box in a BMW or Ford vehicle. More on that later.

Consider installing your battery pack with a cigarette lighter adapter (CLA) connection. While you may be unable to hardwire your battery pack using traditional means, the 12V cigarette socket can still provide a switched power source with sufficient charging current — provided that your vehicle doesn’t have an always-on cigarette socket. This method is often more convenient, as it eliminates the need for complex wiring and can be accomplished with relative ease. CLA installation is an easy plug-and-play solution, which still provides most of the same benefits you’d get by hardwiring your battery pack — the only catch is that you won’t be able to take advantage of fast charging due to the low current of cigarette sockets, so ensure your battery is set to “low” charging. However, it’s worth noting that some newer GM vehicles, like certain trims of the 2024 GMC Sierra, do not come equipped with cigarette sockets, meaning this method won’t work.

Beware of Retained Accessory Power (RAP) fuses when hardwiring. RAP fuses are ACC fuses that remain powered for approximately 15 minutes after the vehicle is turned off, otherwise known as delayed ACC fuses in other vehicles, such as BMWs. Distinguishing between RAP and constant fuses is challenging, as many RAP fuses will get “tripped” and turn back on when basic functions of the vehicle are performed, such as opening a door or using the key fob. To properly identify such fuses, we recommend testing fuses initially, then leaving the fuse box cover and closest door open for 15~ minutes, and then returning to it for testing; a practice we follow in all of our GM installs. Testing should be done with a circuit tester or multimeter.

For battery pack installation, hardwiring must be done to an accessory fuse that is suitably powerful. This can be an issue for specific vehicle models, like the GMT T1XX trucks and SUVs, where the only suitably powerful (20A-30A) ACC circuits use JCASE fuses or other unconventional types. While you are still able to wire into such an ACC circuit, these fuses are rather unique, so there are currently no available add-a-fuses to divert power to new accessories while retaining the circuit’s core function. Thus, wiring to this fuse will require your battery pack to take over the fuse slot, becoming the sole user. As the core function of an ACC circuit can vary between different vehicle models, this may affect unexpected aspects of your vehicle, so consulting a professional is heavily advised when choosing this approach. In the case of the GMT T1XX models, we find that the 12V cigarette socket (if equipped) becomes disabled when a battery pack is installed this way.

Consider wiring your battery pack using a relay. This will likely prove more difficult than wiring directly into an ACC circuit but allows full vehicle functionality to be retained. A relay setup interfaces with any non-essential ACC connection to act as a switch. It allows the battery pack to draw from a suitable constant connection only when the vehicle is running, acting as a countermeasure to protect your vehicle’s battery and electrical system. Depending on your vehicle, this may either be done with or without splicing. Doing this may expose you to high voltage, so this should only be done by professionals or individuals with the necessary skillset and electrical experience.