Ever see a speedometer flip out while parked?

[NorthOrSouth]

Just installed my 'new' Xantrex 458 inverter on our low mileage '92 Monaco. Everything seems to work fine. Turned on the generator so I could fire up the AC and charge up the house batteries and came back ten minutes later to see this on the dash (sped up 2x)

https://www.youtube.com/watch?v=wjnNBEf0z98

Annoyingly its racking up the miles while standing still. Definitely gotta stop that. But I don't know why it's doing it now and never did it with the old Heart inverter. What's going on?

I'm assuming something somewhere is producing a electrical field thats messing with the speedometer sensor? How do I track it? And stop it?

[NorthOrSouth]

@rgatijnet1 I installed it myself but I'm 100% sure no wires were frayed or cut. They are all all wrapped in plastic cable protector and barely got moved between the removal of the old and placement of the 'new' inverter.

It may however be that the sensor wire is somewhere nearby and the old inverter had cleaner output power than this one. This one does make a bit of a buzz when inverting so that might be it.

But not sure how to find the speedo wire. Might have to remove the dash console and track backwards, but even then, I'm guessing that its neatly bundled with all the other wires on the chassis... would be a pain to reroute it away from the other wires... wonder if its not easier to just put a little switch under the dash that disconnects the speedo when the bus is parked. Could even put it on the ignition relay. Hmm...

@MagillaGorilla I checked the pos wires from the batteries forward. Everything looks good and unchanged. Nothing grounding out. Redid the ground wire and fastened it down hard, but no change.

Sent an email to xantrex today, we'll see what they have to say.

[bdpreece]

Your racking up miles but your probably getting really great fuel mileage.

[MagillaGorilla]

I've had this happen and it was due to an electrical surge. My Chassis battery box had broken off and the battery was swinging on the cables. When the battery's positive cable swung and hit the MH frame it would send the tach and the speedo bouncing all over the place.

My guess is that you have either a bad ground or you have a positive that is grounding out. Just remember that the wire that is giving you problems does NOT have to be near the speedo.

[rgatijnet1]

Look for any wires that could have been frayed or cut when the Xantrex was installed. It should be in a basement compartment and maybe the electrical speedometer sensor wires pass near that area of your coach.

[gbopp]

Clicky

I couldn't slow it down enough to listen to the audio.