Trailer Brake Controller adjustment

zeus7625

Member
Probably an elementary question.............but here goes anyway.

NT 21 FBS

I have a very good brake controller (Prodigy P2) installed in my Tacoma that worked well with my 18 ft trailer. I recently traded up to the NT 21 FBS. On my way home from the lot I played with the controller setting knowing that I would have to do it again once we loaded up for the shakedown cruise.

If the setting was too strong on the 18 ft. trailer the brakes on the TT would lock up and I would adjust accordingly.

When adjusting for the NT, I would get a lot of pulsation in the brake pedal (Truck ABS?) but the TT wheels were still rolling. I adjusted until there was hardly any pulsation but I'm not sure if the trailer is braking properly.

I know the TT brakes are electric but are they anti-lock brakes?
 

branson4020

Icantre Member
No. Anti-lock brake technology requires sensors at each wheel, and a connection back to a computer-control unit that can modulate the brakes. Your trailer brakes have none of this.
 

zeus7625

Member
No. Anti-lock brake technology requires sensors at each wheel, and a connection back to a computer-control unit that can modulate the brakes. Your trailer brakes have none of this.

Ok. Thanks.

Not being a wise-acre, what explains the pulsation in the truck brake pedal?
 

jnbhobe

Well-known member
Ok. Thanks.

Not being a wise-acre, what explains the pulsation in the truck brake pedal?

Do they pulsate without the trailer hooked up?? 4-way flashers weren't on were they?? Try using the manual control and see if they pulsate.
 

zeus7625

Member
Do they pulsate without the trailer hooked up?? 4-way flashers weren't on were they?? Try using the manual control and see if they pulsate.

No, they do not pulsate without the trailer hooked up. Sorry I didn't mention it but it was the first thing I checked when I disconnected. I'll try with the manual control and let you know. thanks.
 

APT

Well-known member
How did you setup the gain on the P2?

Scale it all the way down to none.
Drive 25mph.
Manually apply the trailer brakes while turning the gain up to just before lockup.
 

GOTTOYS

Well-known member
The brakes on your truck are not connected to the trailer brakes in any way. Brake pedal in your truck has nothing to do with the brakes on the trailer. Two separate systems. Pulsing in the pedal is usually from the anti-lock system on the truck functioning. Something was causing your truck to loose traction and activate the anti-lock function. Possible the trailer brakes were not helping to stop the unit and the trailer was actually pushing the tow vehicle when trying to stop??..Don
 

BorgX

Member
The brakes on your truck are not connected to the trailer brakes in any way. Brake pedal in your truck has nothing to do with the brakes on the trailer. Two separate systems. Pulsing in the pedal is usually from the anti-lock system on the truck functioning. Something was causing your truck to loose traction and activate the anti-lock function. Possible the trailer brakes were not helping to stop the unit and the trailer was actually pushing the tow vehicle when trying to stop??..Don
Agreed. Maybe the TT brakes are on so lightly that it is pushing/lifting the rear tires on the truck and the anti-locks on the truck are doing their job? I have a 21FBS and have pulled it with both my Trailblazer and my new GMC Sierra and the only issue I have is that after driving for more than an hour, when I stop the TT wheels will lock up when stopping. I have to turn the controller down to stop it... I've had the dealer check the brakes and they test fine... no clue on that.
 

zeus7625

Member
The brakes on your truck are not connected to the trailer brakes in any way. Brake pedal in your truck has nothing to do with the brakes on the trailer. Two separate systems. Pulsing in the pedal is usually from the anti-lock system on the truck functioning. Something was causing your truck to loose traction and activate the anti-lock function. Possible the trailer brakes were not helping to stop the unit and the trailer was actually pushing the tow vehicle when trying to stop??..Don

Agreed. Maybe the TT brakes are on so lightly that it is pushing/lifting the rear tires on the truck and the anti-locks on the truck are doing their job? I have a 21FBS and have pulled it with both my Trailblazer and my new GMC Sierra and the only issue I have is that after driving for more than an hour, when I stop the TT wheels will lock up when stopping. I have to turn the controller down to stop it... I've had the dealer check the brakes and they test fine... no clue on that.

I did the 25 MPH check and had to adjust accordingly. After reading these posts I did the "open hand to the forehead" as the answer was so obvious.

The trailer WAS NOT helping with the braking and the ABS system was doing its job.

Controller adjusted, problem solved.

Thanks for all the replies.
 
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