Does anyone know where the Jake brake module would be installed on a '93 with DDECII? I found the coolant module at the rear of the coach behind the termination box. (Had to remove the top stainless steel cover to access) My jakes do not work and I need to do some volt testing starting at the module. Switch gets power at the armrest.
(11-13-2023, 08:29 PM)BusNit Wrote: Does anyone know where the Jake brake module would be installed on a '93 with DDECII? I found the coolant module at the rear of the coach behind the termination box. (Had to remove the top stainless steel cover to access) My jakes do not work and I need to do some volt testing starting at the module. Switch gets power at the armrest.
It is possible to wire the jakes with simple relays instead of the jake brake module, not sure how Newell accomplished connecting the jakes. Just food for thought. Basically the only thing from the ECM is a signal that the engine is at zero throttle position, this only allows the jakes to come on when that signal is present.
Hopefully someone knows where they hid the jake controls.
Thanks guys. Michael, I do have the guide. I had asked the paint shop if they knew of a company that can take a look at it for me of which they had a good recommendation. I reached out the the referred guy and they do not know how to work on these engines. I guess this will be my first experience of repairs or lack of from an outside shop. I'll dinker with it when I get home. For now, no more mountains until then. (This never worked from the getgo) Coach speeds up quickly on descends and stabbing the brakes every now and then to slow her down still heats them up to the point I feel shuddering. Arizona has really long stretches of descending grades when coming from the 40 and heading back south.
(11-14-2023, 09:36 AM)BusNit Wrote: Thanks guys. Michael, I do have the guide. I had asked the paint shop if they knew of a company that can take a look at it for me of which they had a good recommendation. I reached out the the referred guy and they do not know how to work on these engines. I guess this will be my first experience of repairs or lack of from an outside shop. I'll dinker with it when I get home. For now, no more mountains until then. (This never worked from the getgo) Coach speeds up quickly on descends and stabbing the brakes every now and then to slow her down still heats them up to the point I feel shuddering. Arizona has really long stretches of descending grades when coming from the 40 and heading back south.
Jakes on a DDEC engine are a fairly simple circuit. There is just two solenoids, one on each engine bank. First stage jakes activates one bank and second stage activates both banks. Many times vibrations will loosen the connection to the solenoid on the jake unit itself. That is usually the first thing I check. I will usually use a 12v source and connect it directly to the wire feeding the jakes. Finding this wire on the DDEC engines can be a bit more challenging, it’s almost easier just to pull the rocker covers off and just check the wiring and also just run a jumper to the solenoid and verify the solenoids are operating properly.
I think I figured this debacle out. Since it was a poopie kind of day with down pouring rain, I did some T/S inside. I traced all the wires and figured it out. Relay under kick panel is always powered by key on. One wire goes to solenoids out back. The other wire goes to Jake switch. From Jake switch that wire goes to ECU. I am under the belief that when previous owner had Detroit replace the ECU they (Dealer) did not turn on engine brake feature. I don't think I can turn it on with my DDEC scanner tool. This is my findings.
--Simon
1993 8v92TA #312
(This post was last modified: 01-23-2024, 06:03 PM by BusNit.)
(01-23-2024, 05:58 PM)BusNit Wrote: I think I figured this debacle out. Since it was a poopie kind of day with down pouring rain, I did some T/S inside. I traced all the wires and figured it out. Relay under kick panel is always powered by key on. One wire goes to solenoids out back. The other wire goes to Jake switch. From Jake switch that wire goes to ECU. I am under the belief that when previous owner had Detroit replace the ECU they (Dealer) did not turn on engine brake feature. I don't think I can turn it on with my DDEC scanner tool. This is my findings.
Hmm I will have to ask my buddy on the WL forum, he has done a deep dive into DDEC, actually so much that he is converting his mechanical 6V into a DDEC IV and he is doing all the programming.
