How to Prevent Battery Drain of 2020 Honda Civic When Flat Towing
Updated 09/14/2026 | Published 09/04/2026
Question:
I just got the Roadmaster baseplate for a 2020 Honda Civic. This car has a push button start system. I didnt realize that it locked the steering wheel when the ignition is off. All your writeups for these baseplates for the late model civics dont seem to mention that. Looking online, I find information that mentions leaving the car in accessory mode and then running some type of charge line from the motorhome back to the car. Is that the only option or is there a way to pull a fuse or disconnect the battery on the civic to disable the auto steering lock? Thanks.
asked by: Bob A
Expert Reply:
Hey Bob, so I did a little digging on this and apparently when your 2020 Honda Civic is in ACC mode after 30-60 minutes it switches to a low power draw mode which makes the battery draw pretty low when you'll be flat towing. Now with that said a charge line kit like the Roadmaster part # RM-156-25 is going to still help as it will keep the battery topped off and you wouldn't ever really have to worry about the battery being dead. I would not recommend pulling any fuses or anything and I'd recommend following all of the specific instructions in the owners manual.
Mervin B.
9/8/2026
I would use an ATC fuseholder with an ATC 15 amp automatic resetting circuit breaker. The automatic resetting circuit breaker that comes with the RM 156-25 leaves the 2 post that you hook the wires to exposed. You can drop a tool or set a tool on it and it can go straight to ground and burn the wire up.
Jameson C.
9/8/2026
Tony
9/8/2026
I had a Charing kit instaled with everting else and no problem with battery.
Jameson C.
9/8/2026
Carl S.
9/8/2026
I put a charge line kit on my 2018 Ford F150 so the battery doesn’t die while flat towing. Easy installation follow instructions in package. Pleased with the outcome, easy to confirm voltage from alternator of towing vehicle.
Jameson C.
9/8/2026
Bob A.
9/12/2026
Thanks for the reply, but I can't say I really like the idea of leaving a push button start car in accessory mode running down the highway. Electronics can fail and if it did and went to a shut off state, that would automatically lock the wheel and I would not know about it till it was too late. If it was a key start, then at least it would be a mechanical steering wheel lock and I would be much more confident in it not screwing up. I think the better option is to disconnect the negative battery terminal while the car is in accessory mode (if it is off then the steering is already locked) and then the wheel lock cant engage at all. You also have to make sure the E-brake is set to off as well. The car doesnt do too badly waking up from no battery, it takes a few minutes to recalibrate itself but does not loose many if any settings. I have already tried it and it seems to work well enough. I also think you need to update your information on these baseplates and the issues with the steering wheel locks. There is no mention of it as far as I can tell and it would be better for people to know up front that this is a problem they need to overcome to tow these cars.
Jameson C.
9/14/2026
Product Page this Question was Asked From
Roadmaster Battery Charge Line Kit for Towed Vehicles
- Accessories and Parts
- Flat Tow Wiring Harness
- Battery Charge Line Kit
- Roadmaster
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Denny
9/8/2026
I flat tow my ‘18 Subaru Crosstrek and have to leave the ignition in ACC to keep the steering wheel unlocked. The charge line kit is simple to install and the battery never drains.