Forum Discussion

OldBlackWater's avatar
OldBlackWater
Explorer
Jun 03, 2015

Ford C-Max toad brake indicator light

I recently installed a ReadyBrake to prepare my 2013 Ford C-Max Energi as a toad, and to make sure it's working properly and to be alerted if the brakes are being applied when they're not supposed to be, I'm trying to figure out a way to rig up a relay that switches on a light on the dashboard of my motorhome when the toad brakes are pressed hard enough to activate the brake lights.

Here's my problem: I did a little experiment to make sure the C-Max's brake lights will still be active while towing by putting it into accessory mode and in neutral, and when I went back to check after about 30 minutes, the brake lights were inactive. I pulled on the ReadyBrake cable to activate the brakes, and the brake pedal went down, but there were no brake lights. If I can't get brake light power to activate the relay, my indicator light will not work.

Has anyone been able to rig up a toad brake indicator light on a C-Max or other similar vehicle that deactivates the brake lights while being towed?

Tangent question: I also noticed that my C-Max was no longer in accessory mode after 30 minutes; it appeared to be off. Instead of leaving it in accessory mode, could I just leave it off since it shuts off by itself eventually anyway? What do other Ford plug-in hybrid owners do?

8 Replies

  • OldBlackWater's avatar
    OldBlackWater
    Explorer
    Jul 22, 2015
    Follow-up: I bought the Roadmaster brake switch from etrailer and installed it above the brake pedal. I ran wires to the front of the car and used an SAE 2-pin cable to connect to the wiring I had already installed for the ReadyBrake LED dash indicator light in the motor home. Works great. It only lights up when the toad brake pedal moves from its resting position, and with the ReadyBrake cable having a couple inches of slack, I could tell it only activated the toad brakes in moderately hard braking situations. Lightly tapping the brakes to get the F-53 to downshift on downgrades was not enough to make my C-Max brakes activate, so I'm quite happy with its functionality.
  • OldBlackWater's avatar
    OldBlackWater
    Explorer
    Jun 05, 2015
    My biggest fear is that the breakaway cable gets caught on something and ends up yanking the brake pedal. I already wired up the indicator light that came with my ReadyBrake, but it won't light up in this situation. I know I'm being overly cautious, but having done all the toad prep myself this time I'm afraid of the scenario where I missed something. And if something bad happens my wife would be mad, and I wouldn't have anyone else to blame it on. :B

    If it comes down to it, I did find a brake pedal switch from Roadmaster that is designed for the C-Max, part #751459.
  • tropical36's avatar
    tropical36
    Explorer
    Jun 05, 2015
    OldBlackWater wrote:
    tropical36, that's exactly what I was hoping to do, but my brake lights are basically inactive while being towed so there's no power to trip the relay.

    neschultz, that sounds like my best bet at this point.

    Thank you both for the replies!

    If anyone else has thoughts on this or my other question on accessory vs. off while towing, I'd appreciate hearing from you, too.

    Steve

    I get what you're saying now and one of the reasons NSA went with the brake switch on the READYBRAKE mechanism, itself. I wouldn't call it fail safe, but pretty dependable and as long as you don't forget to hook up the brake cable to the toad. So......you might be wanting to use that, like the majority of users or at least until you figure out something else.
    All this assuming your READYBRAKE is fairly modern, as I'm thinking that the originals didn't have such.
    Speaking of NSA, you might want to give them a call, as they sell optional kits as an alternative and may have one for your application.
  • OldBlackWater's avatar
    OldBlackWater
    Explorer
    Jun 04, 2015
    afrescop wrote:
    Do you have a charge line connected to the C Max? If not the car's system will shut down the electronics.

    I do have a charge line that I connect. It didn't occur to me that it might make a difference. I did my little experiment in my garage and didn't have the charge line connected to the motorhome, so maybe I'll try this again next time I hook up MH to toad. Thanks for pointing this out.

    afrescop wrote:
    Are you saying the key returns to the off position? How can that be?

    I should have clarified that I have the push-button start on my C-Max. If I press the button without holding down the brake pedal, it goes into accessory mode.
  • afrescopXx's avatar
    afrescopXx
    Explorer
    Jun 04, 2015
    Do you have a charge line connected to the C Max? If not the car's system will shut down the electronics. Our C Max has a charge line. The car is supposed to be and always is in accessory mode when hooked to the MH. Had issues initially with the battery running down but once the charge line connection was corrected no tow issues. Brake lights always work. C Max has 53,000 miles of which about 10k are towed miles.

    Are you saying the key returns to the off position? How can that be?
  • OldBlackWater's avatar
    OldBlackWater
    Explorer
    Jun 04, 2015
    tropical36, that's exactly what I was hoping to do, but my brake lights are basically inactive while being towed so there's no power to trip the relay.

    neschultz, that sounds like my best bet at this point.

    Thank you both for the replies!

    If anyone else has thoughts on this or my other question on accessory vs. off while towing, I'd appreciate hearing from you, too.

    Steve
  • neschultz's avatar
    neschultz
    Explorer
    Jun 03, 2015
    Steve,

    During my first towing trip with the Sonic, I discovered that the brake indicator light quit after about minutes due to the same problem. The solution is to wire in another brake switch such as the Roadmaster 751457 connected straight to the toad battery (via a fuse).

    Good luck,
  • tropical36's avatar
    tropical36
    Explorer
    Jun 03, 2015
    OldBlackWater wrote:
    I recently installed a ReadyBrake to prepare my 2013 Ford C-Max Energi as a toad, and to make sure it's working properly and to be alerted if the brakes are being applied when they're not supposed to be, I'm trying to figure out a way to rig up a relay that switches on a light on the dashboard of my motorhome when the toad brakes are pressed hard enough to activate the brake lights.

    Here's my problem: I did a little experiment to make sure the C-Max's brake lights will still be active while towing by putting it into accessory mode and in neutral, and when I went back to check after about 30 minutes, the brake lights were inactive. I pulled on the ReadyBrake cable to activate the brakes, and the brake pedal went down, but there were no brake lights. If I can't get brake light power to activate the relay, my indicator light will not work.

    Has anyone been able to rig up a toad brake indicator light on a C-Max or other similar vehicle that deactivates the brake lights while being towed?

    Tangent question: I also noticed that my C-Max was no longer in accessory mode after 30 minutes; it appeared to be off. Instead of leaving it in accessory mode, could I just leave it off since it shuts off by itself eventually anyway? What do other Ford plug-in hybrid owners do?

    Not sure of everything you're trying to say here, but this should work with any of them and assuming that you don't want to use the actuator switch on the READYBRAKE itself.
    Hang a 12vdc miniature relay somewhere at the third brake light (I just taped mine on to the wires back there) and use it's dry N.O. contacts for completing the circuit to ground. This is done by first supplying power to one side of the LED indicator light on the coach dash and then running a wire for it's return all the way back and through the umbilical cord to the rear of the toad for picking up the relay's said contacts.
    Hence, when the 3d brake light comes on with the slightest depression of the toad's brake pedal, the relay will close and complete the circuit to ground, thereby energizing the dash indicator light.
    Hope this helps.

About RV Tips & Tricks

Looking for advice before your next adventure? Look no further.25,144 PostsLatest Activity: Jun 26, 2025