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Still with the engine brake!

Yahoo Message Number: 86080
The saga of my intermittent Engine Brake continues. I have replaced the OEM switch that CC install for Hi-Off-Lo at the dash, I have checked out all the connections in the bay under the driver and have isolated the Brakeswitch.com box out of the circuit, but no solution so far; except I now have a definitive repeatable time/distance frame. I know I can drive about 20 miles or so and then the engine brake starts to become intermittent for a couple of times then ceases completely (in either Lo or Hi setting). It does not resume after engine restart except after an undetermined period of the engine being off. After it fails the light at the OEM switch continues to work when the accelerator is released and Hi or Lo are selected, suggesting that the problem is after the switch.
I have now found a relay in the mix, in the drivers bay, it is a 301-1C-S-R1 12vdc, a simple plug and play black unit, it is in one of the Bussman fuse boxes along with other relays. I have ordered a replacement.
One of my issues is that to test any change requires an hour or so round trip to confirm.
I have been unable to find any advice to confirm that a relay could fail in this way; i.e. work for a short period then get stuck, maybe due to heat or whatever which clears itself after cooling down. I do not know how to test the original relay to confirm if it is the cause. Anyone have any clues or experience with relay failure?

Michael

2008 Allure 31683, Cummins ISL 425

Re: Still with the engine brake!

Reply #1 –
Yahoo Message Number: 86081
I wrestled with the intermittent engine brake for a long time on my Cummins ISL 370. It finally quit all together and it turned out to be the solenoid wires under the valve cover shorting out against the engine block. The new wires from Cummins revealed a modification to prevent future failure. The reason the engine brake quit permanently was because the shorted wires finally burned out part of the ECM. New wires and rebuilt ECM fixed the problem.

Larry, 03 allure, 30856

Re: Still with the engine brake!

Reply #2 –
Yahoo Message Number: 86082
P.S. When mine quite working, the light didn't come on.

Larry

Re: Still with the engine brake!

Reply #3 –
Yahoo Message Number: 86091
Michael,

That relay inexpensive. I think it is a double pole double throw relay. You can replace it by that part number at any automotive store. It should be about $5. I would replace it and see what happens.
I have had relays similar to this fail both hard failure mode and intermittent. So I think you have a pretty good chance of solving the problem for $5. That is a 20 AMP relay so there could well be heat causing the problem.

Good luck.

George in Birmingham
'03 Magna 6298
George in Birmingham
2003 Magna 6298

Re: Still with the engine brake!

Reply #4 –
Yahoo Message Number: 86102
I have a 1997 Intrigue with an exhaust brake. I had intermittent problems with the exhaust brake not working. All the relays tested good as well as all the interface switches ( cruise control and trans ECM) My problem turned out to be the switch located on the backside of the throttle pedal. I took it out, sprayed some electrical contact cleaner into it and played with the adjustment screw until the exhaust brake activated with the proper movement of the pedal. This is an air activated switch. When you have the throttle depressed air is ported into the switch and opens the contacts. The adjustment allows you to set how much throttle movement you want to have before the contacts are opened. The air switch was very easy to adjust. I only had to turn the ignition key to run (engine not running) and I could hear the exhaust valve cycling as I made the adjustments.

Mike Hergenrather
1997 Intrigue
10313

Re: Still with the engine brake!

Reply #5 –
Yahoo Message Number: 86118
Thanks Mike, however I have an engine brake on my Cummins not an exhaust brake, my engine brake is limited in operation to excess 5 or 10 mph, so difficult for a layman to test when stationery. However I am grateful for the indication, I cannot find any reference to a specific accelerator switch on my engine brake schematic but will physically look today. I note you have a 1997 coach and mine is 2008 so perhaps things changed over the years? Anyone know if Mike's switch was still the way in 2008?

Thanks

Michael

2008 Allure 31683
 

Re: Still with the engine brake!

Reply #6 –
Yahoo Message Number: 86273
SOLVED, I hope!

As previously mentioned I found a relay in the front drivers bay, which was labeled on the inside of the lid as "engine brake load relay". This relay is not described on any of my schematics, especially the page relating to the engine brake!! Although it is mentioned in the wiring list relative to about 5 or 6 wires.
I was able to test the replacement this morning and did well over the 20-30 miles which would have previously seen the engine brake fail, and it continued to work fine. Not only that but I am now able to feel the difference between Hi and Lo which frankly have have been unable to determine in the 18 month I have owned the coach!
So what was causing this relay to give up after a period in use or indeed what its function is specifically I have not a clue. But I hope this post will provide some insite (no pun intended on Cummins software) for anyone with a similar scenario.

Michael

2008 Allure 31683