Jake Brake Foot Switch

[Chargerman]

I know some members have added a foot switch to activate their Jake Brake. I’m tired of taking my eyes off the road briefly to locate the switch. What switch are folks using? Is it a momentary switch ?

Thanks!

[Dr4Film]

Yes it is a momentary switch.

I installed a similar foot switch for the Blue Ox Tru-Center when it was on the coach.

This is what I purchased.

https://tinyurl.com/49crf7pf

[Gary 05 AMB DST]

I just glued a piece of plastic to the exhaust brake switch to give it a different feel from the other switches to locate it. 

Gary 05 AMB DST

[Chargerman]

37 minutes ago, Dr4Film said:

Yes it is a momentary switch.

I installed a similar foot switch for the Blue Ox Tru-Center when it was on the coach.

This is what I purchased.

https://tinyurl.com/49crf7pf

Thank you Richard!

[Bill C]

I would like to have my brake work automatically instead of having to press a pedal. What’s the advantage of the pedal?

[Chargerman]

I don’t leave my Jake brake on all of the time as it makes the transmission downshift every time I I get completely out of the throttle. With the foot pedal I could engage the Jake as needed without looking for the switch. 

[1nolaguy]

Also, as an FYI, leaving the jake brake/ engine brake on at low rpm can cause carbon build up that can create issues. I use to leave mine on when going through town to avoid having to stand on the brakes. I learned the had way this can cause issues with the transmission etc.

 

[Dr4Film]

It is my understanding but I may be wrong since I have never owned a coach with an engine brake, don't both the engine brake and exhaust brake disengage when the speed reaches 15 mph? Not sure what the engine rpm would be at that time but I haven't had any carbon buildup problems that I am aware of after 107K miles on the engine so far.

Can you elaborate some more on this specific situation so I can educate myself as I will be a new owner of a 2006 Monaco Dynasty early next year that has a two stage engine brake?

[Ivan K]

The engine brake settings are defined in the ECM and I can't tell that I understand how exactly this works. I know mine is engaged until really slow, maybe even to 0 mph and I release the foot pedal before it disengages. Maybe Frank might comment on what these Max/Min exactly mean?

Engine Brake Control

"Cruise Control Activation","Disable"

"Cruise Control Speed Delta for Maximum Engine Brake","6",mph

"Cruise Control Speed Delta for Minimum Engine Brake","4",mph

"Engine Brake Delay Time","0.0",s

"Engine Brake Minimum Vehicle Speed","0",mph

"Rate Limit","Disable"

"Service Brake Activation","Disable"

[Chargerman]

I know mine disengages around 20mph or so. I wish I could have my setup changed so that when the Jake activated it doesn’t downshift. So many times on grades just the Jake would be enough to maintain speed without the addition of reving of engine 

Edited December 24, 2021 by Chargerman

[Frank Bergamo]

You can have the Allison program set to any gear when engaging Jake break. Any Allison shop can do this for you. Hope this helps.

[veraken]

Here's a link which may help

https://pacbrake.com/product/c11745-pacpro-foot-switch-kit/

Here also is a link on irv2 on this subject https://www.irv2.com/forums/f115/monaco-sig-jake-brake-foot-switch-321503.html

[dl_racing427]

16 hours ago, Chargerman said:

I know mine disengages around 20mph or so. I wish I could have my setup changed so that when the Jake activated it doesn’t downshift. So many times on grades just the Jake would be enough to maintain speed without the addition of reving of engine 

My 1993 Dynasty had the foot switch as the only method for activation.  I added a rocker switch in parallel, so either method works now.
It also does not automatically downshift, and I often use the Pacbrake in higher gears to maintain speed on gentle grades.  If more is needed I manually downshift.
I like the flexibility this provides.

[Guest Ray Davis]

18 minutes ago, dl_racing427 said:

My 1993 Dynasty had the foot switch as the only method for activation.  I added a rocker switch in parallel, so either method works now.
It also does not automatically downshift, and I often use the Pacbrake in higher gears to maintain speed on gentle grades.  If more is needed I manually downshift.
I like the flexibility this provides.

David, Curious.   Will it up shift automatically or do you have to keep an eye on the RPMs and shift manually?

[dl_racing427]

Ray,

IIRC the transmission controller will not allow the engine to overrev.
In manual it will force an upshift if deceleration, or if accelerating the engine governor will control the revs slightly below that point and just hold the gear.

[Ivylog]

After having a foot switch on my 04 Dynasty, I added one to my 08 Navigator as it lets you coast. Before adding, I raised the Jake on/off switch up (didn’t put all the way back in) so it’s easy to feel. Unlike the Dynasty which shut the cruise off when pressed…I liked being able to tap it to disengage the cruise, this switch doesn’t. 

Edited December 24, 2021 by Ivylog

[Guest Ray Davis]

Thanks David, that's how I figured it worked.

4 hours ago, dl_racing427 said:

Ray,

IIRC the transmission controller will not allow the engine to overrev.
In manual it will force an upshift if deceleration, or if accelerating the engine governor will control the revs slightly below that point and just hold the gear.

 

[Frank McElroy]

On 12/23/2021 at 4:59 PM, Ivan K said:

The engine brake settings are defined in the ECM and I can't tell that I understand how exactly this works. I know mine is engaged until really slow, maybe even to 0 mph and I release the foot pedal before it disengages. Maybe Frank might comment on what these Max/Min exactly mean?

Engine Brake Control

"Cruise Control Activation","Disable"

"Cruise Control Speed Delta for Maximum Engine Brake","6",mph

"Cruise Control Speed Delta for Minimum Engine Brake","4",mph

"Engine Brake Delay Time","0.0",s

"Engine Brake Minimum Vehicle Speed","0",mph

"Rate Limit","Disable"

"Service Brake Activation","Disable"

Ivan - You are reading parameters that can be set in the engine ECM.  In this case, there is an option to have the cruise control automatically operate the engine Jake brake even when the dash Jake switch is turned off.  The cruise control activation would be set to enabled in the ECM.  If you are going faster than 4 mph above the cruise control set speed, the low or minimum Jake brake would come on.  If that doesn't slow you down enough and you are going 6 MPH above the cruise control set speed the High or Maximum Jake brake will come on.  I'm not aware of Monaco turning on this feature when most coaches left the factory.

As for engine brake delay time, its the time after the Jake brake switch is engaged until the engine ECM gives the signal to the solenoids inside the valve cover to engage the Jake brake.   Service brake activation disabled means that just by pressing on the service brakes, the Jake brake won't also be automatically be turned on.  If this feature was enabled, every time you stepped on the service brakes, the Jake brake would come on. 

Yep, lots of parameter options that most don't even know exist.

As for how the Jake brake operates, there are lots of YouTube videos and information on the web.  But, simply put, the Jake brake is a mechanism under the valve cover that changes the valve timing such that the exhaust valves open way early as the piston start to down after the compression stroke.  That means all the compression built up that would normally be used to push the piston down is lost out the exhaust before it helps to push the piston down.  So, very little of the energy used to compress the air is used to push the piston back down.  This is what makes the Jake brake so effective.  The engine is seeing lots of resistance in only compressing air.

Low or minimum Jake uses 3 cylinders.  High or maximum Jake uses all 6 cylinders.

Hope all this helps and doesn't confuse things too much.

[Ivan K]

On 12/25/2021 at 7:48 PM, Frank McElroy said:

Ivan - You are reading parameters that can be set in the engine ECM.  In this case, there is an option to have the cruise control automatically operate the engine Jake brake even when the dash Jake switch is turned off.  The cruise control activation would be set to enabled in the ECM.  If you are going faster than 4 mph above the cruise control set speed, the low or minimum Jake brake would come on.  If that doesn't slow you down enough and you are going 6 MPH above the cruise control set speed the High or Maximum Jake brake will come on.  I'm not aware of Monaco turning on this feature when most coaches left the factory.

As for engine brake delay time, its the time after the Jake brake switch is engaged until the engine ECM gives the signal to the solenoids inside the valve cover to engage the Jake brake.   Service brake activation disabled means that just by pressing on the service brakes, the Jake brake won't also be automatically be turned on.  If this feature was enabled, every time you stepped on the service brakes, the Jake brake would come on. 

Yep, lots of parameter options that most don't even know exist.

As for how the Jake brake operates, there are lots of YouTube videos and information on the web.  But, simply put, the Jake brake is a mechanism under the valve cover that changes the valve timing such that the exhaust valves open way early as the piston start to down after the compression stroke.  That means all the compression built up that would normally be used to push the piston down is lost out the exhaust before it helps to push the piston down.  So, very little of the energy used to compress the air is used to push the piston back down.  This is what makes the Jake brake so effective.  The engine is seeing lots of resistance in only compressing air.

Low or minimum Jake uses 3 cylinders.  High or maximum Jake uses all 6 cylinders.

Hope all this helps and doesn't confuse things too much.

Thanks for that explanation, Frank. I wish to one day find a public document detailing the many settings and values. Some make sense, some make me wonder.

[Frank McElroy]

27 minutes ago, Ivan K said:

Thanks for that explanation, Frank. I wish to one day find a public document detailing the many settings and values. Some make sense, some make me wonder.

The engine ECM settings are pretty well explained in the Cummins service manuals.  You can gain access through Cummins Quick Serve or buy a set of manuals for your engine off eBay.  Not all options are available to all engines.  In some cases, you need to update the ECM with a more current software load to get some newer features like an engine abuse history tracking.  The very basic version of the Cummins Insite software will only allow you to read trouble codes.  You would need to have the professional version or see your Cummins dealer if you want to change settings.

[lindsey_27511]

This device activates the jake brake and transmission downshifting AFTER I press the brake. Take my foot off the accelerator and the RV coasts. 

[Dr4Film]

Don,

That device was made by a guy named Homer Hawks who quit making/selling them many years ago. He made a lot of people happy and a few not so happy. I remember reading about one guy on iRV2,com that claimed it ruined his ECM which cost him mucho bucks to replace.

Another member here named Mel S. has one on his coach and would not want to drive his coach without it.

I have an electrical drawing from another person who designed his own Brakeswitch based on Homer's device.

To read more about this switch go to iRV2.com and search for Brakeswitch. you will get lots to read about.

My 2002 Windsor had been Flashed with the Latching Program from Cummins before I purchased it so it functioned exactly like having a Brakeswitch installed.

[lindsey_27511]

There are many times I just want to coast and let wind resistance or an uphill grade slow me down, like on a freeway exit ramp or when I want to slow down from 60mph for an upcoming speed zone. When I need additional stopping power from a downshift and jake I just touch the brake.
It is a safety feature that works automatically. No fumbling to turn on a switch. Otherwise, you better keep the jake engaged all the time if you expect to manage a panic stop successfully. 
I think it’s a far fetched claim that it messed up an ECM bc I believe it’s just a couple of relays that trigger from the brake lights. It was a super easy install. 
IMHO it’s the best thing since sliced bread and it’s been on my Windsor for 10 years. 

[Frank McElroy]

I don't know when Cummins first added an option to the ECM software but on a 2004 ISL, I see a setting for engine brake control - service brake activation that can be changed from "Disabled" to "Enabled".  This is a setting that can be changed using the Cummins Insite software. 

With an option to activate the engine brake whenever the service brakes are pressed already programmed into the engine ECM, there would be no need for a separate Brakeswitch control box.

[Ivan K]

5 hours ago, Frank McElroy said:

I don't know when Cummins first added an option to the ECM software but on a 2004 ISL, I see a setting for engine brake control - service brake activation that can be changed from "Disabled" to "Enabled".  This is a setting that can be changed using the Cummins Insite software. 

With an option to activate the engine brake whenever the service brakes are pressed already programmed into the engine ECM, there would be no need for a separate Brakeswitch control box.

I believe the option you mentioned is also present in our ISM software: "Service Brake Activation","Disable"