Help checking whether Jake Brake Solenoids are working Detroit 60/Prevost xl45

[rgrimard]

Hello,
I have a 2000 Prevost XL45 with a Detroit Series 60 engine. I would like to know if there is a way to check the operation of the Jake Brake solenoids without pulling the valve cover off. I read somewhere that there was a way to energize the solenoids by jumping from 24v to the solenoid connection in the read junction box. I can not seem to find any documentation on this. Has someone on here done this test? Thank you . Ray 

[thomasinnv]

On a series 60 the jakes would be controlled by the ddec mounted on the side of the engine. I suppose you could find the pinout for your application and unplug the harness and test it that way. You need somebody with a nexiq or similar device to plug in and test it for you would be the easiest.

[freds]

Ah a big hill on and off?

[rgrimard]

never thought of that genius!

[6805eagleguy]

never thought of that genius!

I really can't tell who's playing who here

[luvrbus]

If the bus has the B500 Allison with a retarder the engine may not have Jakes

[Iceni John]

After I rebuilt my Jakes some years ago, I put in a toggle switch that sends 12V directly to the Jakes regardless of the Jakes normal rocker switch position or even if the engine is running or not.   I did this to create an emergency override in case the Jakes' actuating relay failed while descending a long steep hill, and to also help test whether each bank's solenoid is working correctly.   To do the latter, I flip on the new toggle switch, then walk back to the rear start panel and slowly turn on the start batteries' Cole-Hersee master switch; when the C-H switch makes contact I can easily hear each solenoid click on.   Easy!

My busnut friends make fun of all these little extras that I've made, but if they help me diagnose problems or make driving safer or easier then it's worthwhile to me.   I even put in a two-speed Fast Idle switch to bump the revs to either 900 or 1225 RPM, but maybe that's just frivolous!

John