Recommended Parts to Flat Tow a 2018 Chevy Sonic
Updated 10/22/2025 | Published 09/26/2025
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Question:
What’s the difference between a roadmaster bypass double fuse switch and a Curtis double bypass few switch
asked by: Dennis W
Expert Reply:
Hey Dennis, that's a great question. The answer is not much. The Curt Fuse Bypass Switch for Towed Vehicles item # C63HR is 14" long and the Roadmaster FuseMaster Fuse Bypass Switch item # RM76512 is 13" long. Both perform the exact same function, have the same gauge wire, and store two 20-Amp ATM Mini-Fuses.
It looks like you're researching parts needed to flat tow a 2018 Chevy Sonic. Here's a list of the rest of parts I recommend using:
Tow Bar and Safety Chains - etrailer SD Non-Binding Tow Bar for Blue Ox and Curt Base Plates item # e47ZR
Base Plate Kit - Curt Custom Base Plate Kit item # C44ZR
Wiring Harness - Roadmaster 7-Wire to 6-Wire Straight Cord Kit - 6-1/2' Long item # RM-98146-7 and one of the following diode kits:
For LED Tail Lights: Roadmaster item # RO44FR Or For Incandescent Tail Lights: Roadmaster item # RO94FR
Supplemental Braking System - SMI Stay-IN-Play DUO Supplemental Braking System item # SM99251 or item # SM99243 if your motorhome has air brakes
High Low Adapter - The tow bar needs to be within 3" of level. If you measure the height of the inside top of the hitch receiver tube on your RV, and the height difference is more than 3 inches above/below the base plate tab height, you'll need a high/low adapter. I have linked a FAQ article that explains all this in more detail along with our selection of adapters.
What kind of lights does your Sonic have and what motorhome are you going to be using?
You can add this information and any other questions you have where it says Reply to Jerred H and I'll be happy to answer them.
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Product Page this Question was Asked From
Curt Fuse Bypass Switch for Towed Vehicles - (2) 20-Amp ATM Mini-Fuses
- Flat Tow Wiring Harness
- Bypasses Vehicle Wiring
- Fuse Bypass
- Custom Fit
- CURT
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Jerred H.
10/22/2025
Hey Dennis, how did things go with choosing between the Curt and Roadmaster fuse bypass switches for your Sonic? Both seem to work the same, so I’m curious which one you decided to use. Your feedback could help others setting up a similar flat tow setup.