Problem on Jeep Wrangler with Invisi Brake System

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wstevenson94

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We have recently had the InvisiBrake system install on a 2018 Jeep Wrangler JK - 2-Door.  At times when driving down the road, for no apparent reason, we will here a quick beep sound.  When that happens the red ?brake? light on the instrument panel flashes one time very quickly, the speedometer quickly falls back toward "0" and then returns to normal, and the cruise control goes off.  This happen very intermittently and seems to have no effect on driving other than disengaging the cruise control if it is being used.

This issue has only surfaced since the installation of the InvisiBrake system.

Any information/advice anyone can suggest to what may be causing this will be greatly appreciated.
 

SargeW

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Have someone put a OBDII code reader on the diagnostic port to see if there is any codes stored that the Jeep electronics may be storing. If no codes then it is more than likely the way that the Invsi brake is set up. I am not familiar with the operation of that particular brake to say if it is the cause of the errors.
 

8Muddypaws

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The Invisibrake is a fairly simple system.  It triggers when voltage is sensed on the brake light circuit.

Given that, this is what I think is happening.  You have an intermittent short somewhere that is applying 12 volts to the brake light circuit.  This is triggering the Invisibrake and also backfeeding into your coach system, where the 12 volts on the brake light circuit is what turns off the cruise control.

Check the connections on all the terminals of the trailer connector, both ends of the towed cable, and the connector on the towed.

From there check the wiring to the Invisibrake.

It could be an internal fault in the Invisibrake too, but how would you would find that?  Do they offer any support?
 

wstevenson94

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I have been emailing back and forth with Roadmaster Tech Support.  They are doing the best they can, but no real info as of yet.  Thank you for your insight.  I will begin to try to check all the connections on the Jeep.
 

phil-t

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We use the invisibrake system.  I think, first, and the instructions should be with the documentation you got; check and adjust the cable that attaches to the brake pedal in the Jeep.  Sounds to me like it just a bit too short/tight and every once in a while the brake pedal in the Jeep is activating that light (it's supposed to come on when the brakes in the Jeep are working through the invisibrake system).
Just a thought and an easy check.  That adjustment is documentented in the paperwork.
 

John From Detroit

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For those who have this system?
If you are driving the car. Will the Invisi brake engage if you apply the brakes via the pedal?

If I were designing that system I'd insure that is NOT the case

From the fact the Speedometer drops to ZERO I'm wondering if there is a bad connection .Likely a ground, that's causing issues..  This can be caused during install if they forgot to properly tighten a screw.
 

phil-t

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John From Detroit said:
For those who have this system?
If you are driving the car. Will the Invisi brake engage if you apply the brakes via the pedal?

No, but the red light they install in the front of the coach (on a separate wire circuit from the toad) lights when the toad brake is depressed.

Edit ----  I hooked up our toad today, in preparation for next week's departure, (8k mile route).  I forgot one step in the toad setup - my wife was telling me the light and alarm were on - Indicating brake actuation on the toad.  What I forgot about was the adjustable pedals in the toad.  Have to be "up" all the way, to get the proper adjustment on that actuator cable.  So, cable too loose, or too tight will set the light on and eventually sound the alarm in the MH.
Problem was resolved.  It has been since last September since we traveled with the MH.

Take it back to the installer.
 

John From Detroit

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Than you... NOTE that if it is reading the brake light lead... THE PROBLEM MIGHT BE Either the coach or driver.

Fact: I had a brake light switch fail on my Coach.. I noticed the Cruse  control would no longer engage (It sensed brakes on uses the same lead to sense)

This is part of a longer story I'll omit here but the auth-service center found the brake light  switch was the culprit.

Second. Some drivers, I am told (I was not) are taught to brake with left foot (I use right) and to keep left foot on the brake pedal to reduce response time (I reduce response time by NOT CONSUMING ALCOHOL.. EVER (can't stand the .... stuff)).  Well "riding the pedal" can also cause this to happen.

What concern me though is he said his speedometer was dropping to zero.
This indicates a coach issue such as a faulty ground.
 

8Muddypaws

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John,  you may be on to something with the cable being too tight. 

My coach is set up the same way with the LEDs that normally go on the towed extended all the way to the drivers dashboard.  It?s completely independent of the coaches systems and only goes on when the towed brake lights are on.  If there is any backfeed going on I thinking it?s either faulty wiring or a cross connect.

Our towed has additional lights in the lenses that are tied to the coach, but the toweds lights also come on when the brake pedal is actuated.

Way back when we got our first fifth wheel the guy who wired the in bed Bergman connector bent the wires in such a way that they would short out and cross connect occasionally.  Actually the did it pretty consistently and cause brake failures before we even made it out of the lot.  (He stripped too much insulation off the wires.)  I took it back to them twice and they couldn?t figure it out.  I fixed the problem by adding a spacer which moved the Bergman out about 1/2 inch (this eliminated the too sharp bend that caused the wires to short) and re-wired the connector with the correct amount of insulation stripped off. 

People sometimes do sloppy work.
 

phil-t

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Yup, the speedometer and cruise are a puzzling peice.  I was only trying to point to a possible simple solution, in the actuator cable adjustment.
Another possibility is the lack of a diode on the brake light circuit in the toad - allowing current back to the brake system in the tow vehicle.  You can check the connector on the toad with a test lamp - apply the toad brakes, see if there is current on the brake circuit at the connector.
Basic invisibrake install carries the brake/signals, running lights, ground to a flat four connector plugged into the invisibrake controller, out of the controller, wiring to the toad lights with diodes preventing back feed to the controller; wiring to the actuator for the brake pedal and a lead from the toad brake light switch to the alarm/light installed in the front of the tow vehicle. That actuator cable is adjustable and there is a (force) adjustment dial on the controller.  FYI, in the two years we've had this setup there has been no adjustments necessary and no problems.
Hopefully you find a simple solution.
 

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