Jake brake problem

[Georgia Mike]

Since I bought our Dynasty the Jake brake can’t be turned off. The on off switch does light up when you push it on but doesn’t disengage it and the hi lo switch doesn’t do anything either. I can’t seem to find any info on this or any site about it being stuck on just not working. I know a lot of people just leave theirs on most of the time but I would like to turn it off especially in bad weather. Does anyone know of a fuse location or something to check I can’t seem to find much information about this particular problem.

[vito.a]

I assume you have an ISL 400?  Does your Jake brake function at all?

When you turn your cruise control on does it cancel your Jake brake?

Have you lifted the switch panel and looked for wires that have shaken loose or disconnected?

[Orrin C]

Please check the switch at the accelerator pedal.  Are you sure it’s a Jake brake and not an exhaust brake 

[Georgia Mike]

Thanks for the replies. It is the isl 400 and I haven’t taken apart the panel to look at the switch. I can use the cruise control just fine thankfully but as soon as I tap the brake or turn off the cruise control the Jake brake is on. I don’t believe it’s an exhaust brake because I have the main on off switch then a high low switch. Fortunately it seems to be stuck in the low range only 3 cylinders as I I said before the high low switch doesn’t seem to do anything of course I have only tried it a few times and maybe I was going to fast for it to go into the high range. I didn’t know there was a switch at the accelerator petal but it does disengage When I hit the accelerator as it’s supposed to. I will take apart the arm rest console and look at the switch first but I’m not confident that’s the problem

 

[Orrin C]

If it goes off when you touch the accelerator pedal, that's good.  It could be that you just have a bad switch.  If it works on low, won't turn off, and does not engage high when you have the switch set to high.  I think it is the switch.

[Ivan K]

Have you seen this discussion, potential ECM setting, at the end of the topic, about automatic Jake activation with service brakes as Frank explained? Does it look similar in a way?

 

[Georgia Mike]

Thanks for the link….So what your saying from what I read that someone may have changed the ECM settings to have the Jack brake on all the time?  I haven’t looked under the dash near the accelerator pedal but does this box in the picture add a separate pedal or a switch to the back of the accelerator pedal?

[Ivan K]

3 hours ago, Georgia Mike said:

Thanks for the link….So what your saying from what I read that someone may have changed the ECM settings to have the Jack brake on all the time?  I haven’t looked under the dash near the accelerator pedal but does this box in the picture add a separate pedal or a switch to the back of the accelerator pedal?

I don't have a first hand experience with either of these recently discussed possibilities since my factory foot switch works just fine. Just wanted to make you aware of their existence. I have a way to check the ECM setting and brake state but I am in the boonies outside Dallas...