[Pennidragon]

Originally Posted by rickst29

It sounds like your (maybe default) Echo settings are causing it to over-react: adjusting braking power (Voltage) by too much at a time. If that guess is right, then:

When it "feels" that you're not slowing down fast enough for your TV brake pedal position, then it raises the trailer brake power by too much - and you feel the Sienna being dragged back into the Trailer. (With your "submarine" effect being caused by your hitch being a bit out of line, or your WDH being mis-adjusted, or both factors).

Then a moment later, it feels that you are being slowed down too FAST for your brake pedal position - and it drops the Trailer Brake voltage down by too much, the Trailer pushes into the Sienna - and the opposite bounce effect occurs (again because the hitch ball height isn't lined up LEVEL with the TM A-frame ball receiver, or because WDH is mis-adjusted).
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These 'submarine' effects are dangerous, you probably need to change your WDH head height. The hitch ball, in the Toyota hitch receiver and WDH head, needs to within an inch of "level" with the bottom of the hitch ball receiver on the TM A-frame ... with that A-frame, and the entire TM, perfectly level (held up by the trailer's A-frame jack).

Then, on a level segment of a parking lot or residential roadway parking space, measure the highest point on each of the 4 Sienna wheel wells to the pavement, before attaching the TM. Latch in the hitch ball and drop release the TM hitch jack, and adjust the WDH so that each of those Sienna wheel wells has dropped by the same amount of distance (closer to the street surface). That's how you tune the WDH force.
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There should be an ability to vary the "sensitivity" of your Controller, and reduce the amount of voltage change which is being made by the accelerometer changes.

I'll have to check the WDH then. The dealer installed all the components, including the hitch on car, harness, WDH, setting the WDH up. If it's something wrong with the install I'll just probably have to bring the TM back to him. Just annoyed if I have to make a trip back to him to fix this. I'll try to see if I can get the manual online and see if I can make sure the install is all within spec and see if I can make any adjustments to it.