GM Genuine Parts 84108373 Black Trailer Brake Control Switch Assembly
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Product description
If your GM setup uses a trailer brake controller, the switch assembly is one of those small parts that can still cause a big headache when it’s worn, damaged, or simply not behaving like it should. The GM Genuine Parts 84108373 is designed to match the original factory component in fit and function, which matters if you want a straightforward replacement rather than a “maybe it works” gamble.
On paper, this looks like a proper OE-style swap: GM Genuine Parts recommends it as a replacement for the original component, and it’s manufactured to the original equipment specifications for shape and function. That’s the kind of detail that tends to make troubleshooting easier when you’re focused on getting everything back to normal.
What it is and what it’s for
This GM Genuine Parts part is a trailer brake control switch assembly (black). In plain terms, it’s part of the control interface that helps manage trailer braking behavior through your vehicle’s system. When the switch assembly isn’t right—whether due to wear, damage, or age—using the trailer brakes can feel inconsistent. A replacement like this is meant to restore the intended operation.
The biggest reason to consider OE-style replacement
A lot of aftermarket options vary in how tightly they match the original. Here, the pitch is pretty clear: it’s recommended by GM for the factory component, built to OE specifications for fit, form, and function. That matters because the “feel” and the physical alignment are often what determine whether a replacement just snaps in cleanly and behaves predictably.
Worth noting: the listing describes the controller material as ABS plastic. ABS is common for automotive switch components because it balances durability and form stability, but it also means you should still treat it like a plastic part—avoid harsh impacts and don’t expect it to tolerate abuse.
Key takeaways about day-to-day use
In everyday use, a trailer brake controller switch assembly mostly needs to do two things reliably: operate consistently and remain stable in its mounting/fit so the system doesn’t feel loose or off. With OE-style specs, you’re aiming for normal operation—no weird alignment issues, no “it works sometimes,” and fewer surprises when you’re towing and adjusting braking.
What stands out (and what might not)
What stands out here is the alignment with the original GM component. If your goal is a like-for-like replacement that prioritizes correct fit and function, this is the type of part that usually makes the most sense.
That said, it may not be the best choice if you’re trying to build a custom trailer braking setup or if you’re replacing a part but don’t have confidence it matches your vehicle’s original configuration. With switch assemblies, compatibility is often the make-or-break factor. If the switch assembly isn’t the exact one your system expects, even a high-quality part can leave you with the wrong outcome.
It also stays in the “replacement” lane rather than offering any dramatic upgrades. It’s not presented as a performance or feature add-on—more like a restore-to-OE option.
Tech specs
- Name: GM Genuine Parts 84108373 Black Trailer Brake Control Switch Assembly
- Type: Trailer brake control switch assembly
- Color: Black
- Material: ABS plastic
- Manufacturer positioning: GM recommended replacement for the original factory component
- Origin noted: Manufactured in China
Who this fits best (and who should pause)
It makes sense if you want a GM-recommended replacement for a factory trailer brake control switch assembly and you’re focused on getting your towing controls back to normal operation.
You may want to skip it (or double-check first) if you’re not sure the 84108373 part number matches your vehicle and trailer brake controller setup. Trailer brake controller systems can be sensitive to exact component matching, and this listing doesn’t spell out vehicle compatibility details. When that information isn’t clear, it’s smart to verify before buying.
How to decide before you buy
Here’s what to check so you don’t waste time:
- Confirm the part number matches your current hardware.
- Make sure you’re replacing the same type of component (a switch assembly, not a different controller part).
- If your existing switch feels damaged or inconsistent, consider whether other parts in the trailer brake control circuit could also be contributing. Replacing only one piece can help, but sometimes the issue is broader.
A small practical example: if your switch responds slowly or stops working when you need it most, replacing the switch assembly with an OE-style part is a direct way to address the control interface—rather than guessing with unrelated components.
Final verdict
This is a solid, OE-aligned replacement choice if you’re trying to restore a GM trailer brake control switch assembly to correct fit and function. It’s not meant to be a creative upgrade, it’s more about returning the system to the way the original was designed to work. If you can confirm the part number and component type match your setup, it’s the kind of purchase that tends to pay off in fewer headaches. If you can’t confirm compatibility, it might be a frustrating buy—trailer brake systems don’t leave much room for “close enough.”
Mini FAQ
Is this meant to replace the original GM factory component?
Yes—this listing positions the part as a GM-recommended replacement for the original component of your GM vehicle.
What material is the switch assembly made from?
The controller material is listed as ABS plastic.
Does it come pre-colored or finished?
The assembly is described as black.
Where is it manufactured?
It’s noted as manufactured in China.
Should I buy this if my towing brake issue is electrical?
If your problem is specifically tied to the switch assembly itself, it can be a direct fix. But if the issue is caused by another component in the trailer brake controller system, replacing only this part may not fully solve it—so verify the symptoms first.