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2002 Signature Jake Brake electrical troubleshooting help

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I just got my 2002 signature with ISM 500 back from the Cummins shop.  I had requested they repair my jake brake system which has never worked since I purchased the coach. They said the problem was OEM electrical and would not work on it.  So I need help.  

My Signature has the foot switch and arm rest hi/lo switch.  I check the foot switch and it is passing 12v. I have the arm rest apart so can see all the wiring. The hi/lo switch is connected and has a voltage reading of 9.5v all the time-its there even when the key switch is off.  The foot switch has no effect on the hi/lo switch. That’s where I am…

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I don't know if you already have wiring diagrams on your coach but if you don't, the closest set we have is for a 2003 Dynasty and hopefully the Jake brake section is close to your coach. 

I'm curious if the Cummins shop was electronically able to activate the Jake brake using their Insite software just to be sure that the electrical solenoids and the mechanical systems on the valve train are properly working.


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I love the way the low setting on the exhaust brake works on our dynasty.  It interfaces with the the Alison and is perfect for rolling hills terrain.  I hope you didn't take your coach to the Cummins in Tampa.  That shop is a bunch of duds.

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Hello Frank.  Thanks for your help. I do have the wiring diagram for the 2002 Signature and can share it if needed. I have been studying it. I have not been able to identify where some of the components and relays are that the drawing refers to and where the signals are all going.  I am pretty savy with electronic  installations and computer repairs, but  I am not able to understand the Monaco drawings and the previous mention volagecreadings at the foot switch and the hi/lo switch. I need some experienced help. 

When I picked up my coach from the Cummins shop in Ft. Myers the service manager was not available to answer the question about testing the jake brake solenoids with the Insite program.  My bill says “Hook up Insite No faults, troubleshoot engine brakes inop on the oem side”.

I’m not sure  if that means the actually tested the two solenoids under the valve cover. I have been trying to get the answer. The assistant manager was a not helpful and  had no information about the work performed except what was written on the ridiculously hugh bill. He said I would have to call and ask the manager the following day.  I have made at least 8 calls and left voice messages and sent an email for the manager-but no response to date.  It’s been about 10 days since I left the shop.  At this point I can not recommend doing business with them.  

I have taken several photos of the pages of the manual that reference the engine brake relays, switches, etc.  I would appreciate your advice on what to look for. 


John, J. Monaco Signature 2002




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I confess I know NOTHING about Jake brakes.  But I did cure an inoperative one once by unplugging a connector that went through the valve cover, cleaning it (oil-soaked and dirty) with WD-40 and reconnecting it.

Sooooo many electrical problems on our coaches are due to poor electrical connections.

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I was having a problem with the Jake brake not activating on our 2001 Dynasty and the foot switch showed 12 vdc going through it.  However, when putting a load such as a light bulb on the switch it failed.  A new $15 replacement cured the problem.



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Good News!

Jake Brake Problem Solved.

I found a bad butt connector in my Jake brake wiring.  It was a small red wire  buried in the bundle under the drivers arm rest.  I just came back from a test drive and my Jake brake now works like it should.  

It was a good learning experience.  I tested the engine brake relay and the cruise control relay in the FRB in the process.  Each checked out Ok.  Now that the wiring problem was connected the cruise control relay in the FRB clicks when you activate the foot switch.  I did change out the foot switch for good measure.  The old one did pass current but it had about 18 ohms of resistance compared to the new one which had zero resistance when activated.  I found one on Ebay for about $20.00.

Thanks to all that replied with suggestions, etc.


John J 2002  Monaco Signature

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