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Technical Support / Re: Fast Idle switch Engine Brake
« Last post by Nicholas Soldevere on February 21, 2026, 03:11:27 PM »Nick,
To answer your question, A pac brake closes off your exhaust from escaping at the manifold output thus creating a back-pressure in the engine to slow you down. It also causes the transmission to down shift to assist in slowing the coach down. A Jake brake works differently, It turns the engine into a Compressor momentarily to slow you down. If you push the switch forward it is max engine braking and it automatically shifts the engine from 6th to 4th gear to assist in braking. Pushing the switch towards the rear is less engine braking. Caution: Driving at 70 mph and engaging the Jake brake may OVER REV the engine and cause damage. Do you have a Smart Steering wheel?. If so, it may be the issue if you have one. The cruise control and fast Idle are controlled by it. Incidentally, if your cruise control and your jake brake are both engaged at the same time there is a conflict. It is common issue for the contact plate under the steering wheel to get dirty from the carbon brushes contacting it for 23 years. It sends misinformation to the VIP control module that executes the commands you are asking for. I just re-read your original post, if your fast- idle switch is on the side console, then you do not have a smart wheel by VIP. Hope this helps, Fred
Thanks Fred, I do believe I have a smart wheel, it has buttons for lights and cruise, I don't know why there is also a Fast Idle switch as well on the side panel. I have found on the one test drive I did yesterday which wasn't out on the highway as I was just checking the eng brake. The cruise didn't engage with eng brake switch on. Now, I'm thinking and have known for awhile that I need to get into that wheel and clean those contacts on the clock spring as the cruise control functions from the wheel aren't all there, all I have is On/Off and Resume, so I cannot change the speed, 68.5 mph is where is stuck at, which also seems to be the sweet spot for the rig anyway, so. The cruise is problematic, another issue I discovered last trip out is , it doesn't automatically disengage when stepping on the brake.
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