Speedometer Intermittent Problem

[Bob (WA0MQE)]

As signature states, I have a '06 Camelot PDQ. I have an intermittent problem where the speedometer justs drops off from time to time. Doesn't seem to matter what my speed is when it happens. It will indicate properly then when it does goof, the needle drops toward zero. If I'm moving around 30 or under it usually drops all the way to zero, but when I'm at highway speeds, 60-65, it will drop toward zero but then recover itself and jump back up to the proper speed.

I spoke with Monaco and they were little help. Said it's probably next to impossible to find such an intermittent problem. I took the cover off the dash to look behind the instrument cluster and "WOW" what a bundle of wiring mess in there. How anyone could troubleshoot in there is beyond me, and I'm usually pretty good at this sort of thing.

I'm hoping I'm not the only one that's had this problem and someone can offer some help.

[Drifter]

Start with the ground wire connections.

[Mike Canter]

Bob, if I remember correctly the pickup for the speedometer input is on the side of the Allison transmission converter housing. You might want to take that plug off and put it back on and make sure it is dry and tight. The other possibilities is that the one of the little nuts that hold the wires on the back of the speedometer has come loose so you might want to check all those. What happens with the cruise control during the time that the speedometer screws up. Does it speed up or slow down? If it remains constant then that should indicate that the pickup on the transmission is good and that just the speedometer has the problem.

[94-Newmar]

I have the opposite problem with mine.. Just idling parked my speedometer will read anywhere from 5-10mph just sitting still. If I hit any buttons on the dash it will either jump to 30mph or go back to zero. Weird because it doesnt always do it.

[Gordon66]

I had a similar issue. It was the large plug (24 pin) in the front of the coach between the front electrical box under the drivers window and the chassis. This plug connects the chassis harness to the harness that feeds the dash components. Mine was in the center of a ball of wires in plastic looms all wadded up in a ball tied together with tie wraps. Not easy to find. The plug was not completely pushed together so it was loosing contact. There are two of these plugs one in the front and one in the rear. You might check both of them. I pulled the plugs apart and cleaned with contact spray and plugged them back together and put a tie wrap around the plugs pulling them together securely.

[mahon1993]

I had speedo problems and went to all the trouble to replace the speedo head. Still didn't solve the problem until I ran a seperate 12ga ground wire from the speedo ground terminal to a good chassis ground. Solved my problem like magic.
Greg

[MCDDY]

On our Windsor, the speedo does just the opposite now and then, usually when we 1st start out in the AM. Might be running @ 62 (GPS) speed on the highway, all OK, speedo reads about 3mph. fast. Then occasionally it will take off to 75 or 80mph. with no change in actual speed on GPS. May last 30 min or couple of hrs. Probably a ground but it's such a *itch to get into the dash as ours doesn't have an access panel on top. Anyway, I know that it the tach is reading 1475 RPM, we're going 62mph.

Dave

[jwinston]

99 windsor added addition ground wire from chassis ground to speedo ground .. speedo now reading correctly. before speed indication varied with MH at constant speed.. good luck

[HR-TX]

Might not be important to some but you are treading on a huge coach value issue anytime you have a spedo issue. Since the spedo also runs the Odo, you can easily end up in a TMU (true mileage unknown) state with your coach.

The dealer can plug a tool into the engine / trans diagnostic port (on elec control engines) and get a very close number of miles from the computer. If this is more than a few percent off the odo reading, the coach will be considered TMU and the value goes to pot real fast. I know this because I just bought a coach at about half of retail because it was found to be TMU. After thorough inspection I believe the odo mileage to be close, but the law says it still has to be TMU.

BTW, another thing I learned is that I can't get an extended warranty on the coach because of this either.

Still a great deal for me though.