2007 Monaco Diplomat Cruise Control Vibration
I just recently purchased a 2007 Monaco Diplomat with the Cummins ISL 400HP motor. When I activate the Cruise Control it seems to vibrate the rearend so bad I have to turn it off. After more trial and error. This is what I have discovered.
When I start out, if I activate the cruise control at 50 mph and work my way up to 70MPH it works fine. When I stop for a break, and turn off the engine. Get back on the interstate and try to reset it at 70 MPH the vibration starts immediately.
NOTE: When it was working fine, I was hitting the side of my steering wheel to try and simulate rough rode conditions and it did not create this issue. Loose wires in the steering control unit is not the issue.
With the cruise control on, if the vibration starts I can give it more pedal and pass my pre set speed of 70 ( or any pre-set speed) it stops. The minute I lift my foot off the pedal and the speed drops below the pre-set speed and cruise engages by adding throttle and when it seems to get close to the pre-set speed to back off the throttle is when the vibrations starts back.
There is a few times I can set the speed and drive for 1/4 mile with no problems, what I noticed is my PCI ( percentage of Load ) numbers seem to bounce all over the place just before my Cruise starts to act up. This is looking at the Aladdin system information screen.
This is more prevalent on rough interstates. I have only taken 2 trips and talked to a couple of shops that have never heard of this before.
Auto Mechanic by trade (not diesel or Motorhome). It seems like to me, is the system is trying to control the speed to rapidly by engaging the throttle to quickly and releasing to quickly which is causing the vibration. I can come close to simulating this with my foot hitting the pedal rapidly manually with cruise off.
Anybody else heard of this or run across it. Would like to fix it before next trip.