Trailer Brake Controller will limit engine RPMs?

"It's ALWAYS worse when the brakes are very hot too. Like after being on the highway for a long time."
This doesn't sound right to me. The brakes should not be hot while running down the highway, unless your riding the brakes, have bad wheel bearings, driving in heavy stop and go traffic, or the brakes are set too tight.
You may want to have your braking system checked out by someone who knows RV braking systems.

Awesome, what good answers!

I think the replier is right about the clunk. I think the van is somehow delaying the signal to BRAKE. I know the van has that crazy option to flash the brake light up high in the middle of the back.

I bet a mixture of that and the fact that it's a Minivan with NO prewire harness available means that they spliced into the signal out of the outboard braking computer and it's somehow delayed enough that the trailer CHUNKS.

It's strange because it happens at the EXACT same spot in the braking process EVERY time. There's about 1 inch of brake you can VERY lightly apply, but ANYTHING over that and BAM, HARD CLUNK.

It does sound like it's the trailer running into the ball on the van. because it jerks the van forward then back quickly.

It's ALWAYS worse when the brakes are very hot too. Like after being on the highway for a long time. You don't use them out there, but when you're back in town, ohh mama you have to be SO careful.

But how are we going to do awesome burn outs without power braking?? Guess we need our low rpm, high torque motors again!

I can see Motor Trends and Car and driver's road test giving poorer performance since they need to power brake most vehicles to get them into their rpm sweet spot for 0 - 60 mph launches. NO more.

beemerphile1 wrote:
I don't know anything about your vehicle but will make a WAG that may be the answer.

Some vehicles that have 'drive by wire' incorporate a brake disable of the throttle. If you have 'drive by wire' that may be what is happening. When you activate the brake it shuts down the throttle.

That should be the correct answer.

The deal is with modern day vehicles they use what is called "drive by wire". Simply put what that means is instead of using a direct steel cable from the gas pedal to the throttle plate (which is what was used years ago) your gas pedal is now connected to the engine computer.

The engine computer takes the gas pedal position info and operates the throttle plate via a small servo motor.

However due to several famous runaway vehicles and a huge recall, the NTSB now requires ALL vehicles using "drive by wire" to have some sort of brake override system.

What this means to you is you can no longer ride (or touch) the brakes while driving above idle speed.

If the computer detects the BRAKE signal at the same time as you are pressing the gas pedal the computer COMMANDS the throttle plate to close.

What does that have to do with your problem?

Many brake controllers are actually wired to LIGHT the brake lights if the manual override on the controller is activated.

Basically your controller as wire is giving the engine computer a false brake signal.

Can this be fixed?

Not sure if it is possible to do since your controller depends on getting the brake light signal to activate the controller under normal usage. If you disconnected the brake light wire then the controller will not work since it wouldn't get the signal from the car.

The only things I can think of is find a different controller which either does not send a brake light signal while using the manual override or can be configured to not send that signal to the car.

Alternately if you are handy with electronics it is possible to wire a diode to the brake light wire. The diode can act as a one way device letting the car to controller signal through but blocking the controller from sending a signal to the car on the same wire.

I don't know anything about your vehicle but will make a WAG that may be the answer.

Some vehicles that have 'drive by wire' incorporate a brake disable of the throttle. If you have 'drive by wire' that may be what is happening. When you activate the brake it shuts down the throttle.

As for the clunk, it sounds like your controller needs adjusting so it activates brakes sooner so the trailer does.not hit the front of the coupling when the van slows down or speeds up

I don't know, but I am thinking that potential solution to the problem, which may be less expensive than letting the dealership hillbillies ( your word ! ) troubleshoot it, would be to buy a prodigy controller and the "correct" Nissan-to-prodigy plug and play underdash wire harness.