Jake Brake Latching

William Schnieber · 04-21-2008, 06:41 AM

Has anyone had their Jake Brake reprogrammed to automatically go on when you hit the brakes without having to fumble for the switch on the dash. In an emergency I think this whould be very beneficial. Towing a F-150 I have it on most of the time, but it would be nice to coast with out the JAke always going on.

William Schnieber · 04-21-2008, 06:41 AM

Has anyone had their Jake Brake reprogrammed to automatically go on when you hit the brakes without having to fumble for the switch on the dash. In an emergency I think this whould be very beneficial. Towing a F-150 I have it on most of the time, but it would be nice to coast with out the JAke always going on.

EngineerMike · 04-21-2008, 07:23 AM

I don't think jake-when-using-service-brakes is a programmable feature. Our coach has the jake programmed to
a) when switch is off, no jake under any circumstance, and
b) when switch is on, to i) operate during cruise control, so the jake kicks in when cresting a hill to keep the coach's downhill speed in check, and ii) when not in cruise to decelerate by jake when foot is off accelerator.

Our 06 didn't have that feature turned on; coach would run away on any dowhill, even slight, during cruise, but otherwise operate as above. I believe Cummins software can be used to program at least the ISL coaches either way. Don't know about PacBrake coaches.

What you may want is Brakeswitch which uses brake light signal to turn the jake on. You splice into the brake light wire & jake switch circuits. The jake switch remains operative so you can switch it on at any time, but when you brake the Brakeswitch preempts a jake-switch-off condition to employ the jake.

Here is a previous thread discussing the options.

**Route 66** · 04-21-2008, 07:58 AM

The Cummins engines can indeed be reprogrammed for the latch mode.

THIS THREAD from a couple of months ago has more info.

William Schnieber · 04-21-2008, 09:25 AM

Why would I choose a brake switch over reprogramming and what are the cost diffs. The RV"S in the shop now, so now might be a good time. It's been in the shop for 5 MONTHS, due to warrenty issues. I guess I won't have to worry about that any more.

EngineerMike · 04-21-2008, 10:21 AM

The Brakeswitch is different than the available programming (I'm pretty sure).

Cummins programming can give you the options I state above for either cruise uses jake to manage speed or cruise disables jake.

The Brakeswitch operates the jake when you step on the service brake (SB) pedal, regardless whether the jake switch is on or off, whether cruise is on or off, whether programming is set one way or the other

I'm not sure why Cummins doesn't use SB signal to engage jake as an option; the ECU monitors SB signal in order to disengage cruise, so it is an available ECU input.

Mike & Mike · 04-21-2008, 01:56 PM

I remember a recent discussion about jake brake use and the most important thing I remember from that discussion is that you don't want to use the Jake on ice and you want to be very careful using it in snow. So, anything automatic that enables the Jake when the Jake switch is OFF (stepping on the brake pedal for instance) would be a bad idea in my mind.

Cheers!

Tom and Patty · 04-21-2008, 08:14 PM

Patty and I can attest to the jake (in our case exhaust) brake on ice

rmmpe · 04-22-2008, 01:49 AM

I see merit in the modes of operation stated above, if they were independently selectable.

Unfortunately, in my case, the time lag between throttle-drop and Pac Brake actuation makes it difficult to determine exactly when the exhaust braking will influence deceleration.

Is this time-lag common to all?
If not, any suggestions as to how I can get the actuation cylinder to extend immediately upon throttle-drop or switching?

Jeff and Cheryl · 04-22-2008, 06:23 PM

Bob,

I have a 2 to 3 second lag between the time I remove my foot from the accelerator and the time the Pac Break activates. This is from 60 mph. At slower speeds, it seems to have more of a lag before kicking in.

Nick Escamilla · 04-22-2008, 08:16 PM

I posted this before on the same subject.
I recently added a 2 pole relay to operate and turn the Jake brake on only when I apply the brakes. If I don't step on the brake, Jake doesn't go on and I coast. I leave the Jake on high. I had to add a micro switch to the accelerator pedal, this allows me to turn off the Jake if I accelerate. If you are interested in adding this simple circuit contact me. It works great and you use a lot less braking. You will need some electrical experience and fabricate a bracket for the micro switch.

rmmpe · 04-23-2008, 02:31 AM

My Alpine is pretty smart. At speed, when the Pac Brake switch is in the "On" position and the switch at the pedal is made, the Pac Brake actuates but the Trans does not shift to 4th. Only when the RPM drops low enough to safely go to 4th will it do so. Basically, I am happy with the way it's set-up. However, I am not pleased with the delay between when the throttle is dropped and when the cylinder actuates to shut the butterfly.

Everything is free, so it's not a mechanical thing.

I am seriously considering a simple series circuit that will directly control only the solenoid/cylinder sequence. The programming will remain unchanged.

Any thoughts on that?

Rick Coleman · 04-23-2008, 05:07 AM

I have Nick Escamilla's set-up on my coach and it makes it a dream to drive. Hands always on the wheel, not reaching for a switch. Really safe when on curvey and hilly roads. Just before WRV closed it's doors I had told Burk Morgan about it and told him it should be standard equipment in the name of safety. He seemed really interested. Of course, that's not going to happen now...