Vitron BMV-712 Smart--plus serious knocking inside

[mikejeane]

I have a new 2022 Isata 5 and on the second time I used the unit the vitron battery monitor jumped from a zero reading to 13.4 reading, then went blank. Sort of like --it came unplugged. It is wall mounted and I don't see a way to check it out in the back to see if it is still plugged in.

My second problem is even at very slow speeds--5 mph-- there is a loud knocking somewhere in the front of the unit. It sounds like something is suspended inside a wall and is swirling around and bumping into things. Anyone else have a similar problem as these two?

[Half Ton Heavy]

Did you check the wiring at the shunt for any loose connections, including the positive wire?

[TitanMike]

Originally Posted by Half Ton Heavy

Did you check the wiring at the shunt for any loose connections, including the positive wire?

Also check the fuse holder in the small red wire connected to battery positive and shunt. Any loose connection here will do exactly what you describe.

As for the "Knocking" I recall reading a while ago how someone found heavy wires in a wall that were causing this.

[Reverse_snowbird]

Since you have a brand new unit, you might want to check with the dealer and get it in for warranty work before you break down on the road.

[Theo]

Regarding your BMV issue:

There are at least three possibilities that may be causing your BMV to lose power. First, disconnect the negative wire from the battery. Then, starting from the positive battery terminal, do the following:

1. Find the thinner red wire (with an inline fuse) attached to the positive terminal. Ensure that this wire is firmly attached to the terminal. Perhaps a cleaning of the terminal and the connectors attached to it may be in order.

2. Follow this wire from the terminal and locate its inline fuse holder. Unscrew the holder, remove the fuse and use contact cleaner to clean the holder's contact points. Reassemble the fuse holder.

3. Continue to follow this red wire to the point where it connects to the shunt. There is a pin at the end of the wire that mates to a friction connector on the shunt. Remove the pin, clean it and the interior portion of the shunt's connector, and reinsert the pin. Note that the shunt has two pin connectors; make sure to reconnect the red wire to the connector labelled "+B1". The "+B2" connector is used for the (optional) temperature sensor.

4. Tuck away the red wire, reconnect the negative wire to the battery and check the BMV.

In the three years I've been using the BMV, I have had to clean the fuse holder...but only once. YMMV.

[mikejeane]

The unit is brand new. Battery compartment is tight and clean. I changed the fuse in the small red wire and pulled on it where it attaches to the shunt--everything is tight. Granted, this Dodge 5500 rides rough so things can get shaken up pretty good. I am thinking that it might be where the wires attach to the back of the display, but I can't figure out how to get the display out of the wall. No screw plate to work with.

[Theo]

Originally Posted by mikejeane

{snip}...No screw plate to work with.

Actually, the silver surround around the bezel is actually press-fitted onto the gauge. You should be able to gently pry it off. The gauge itself is attached to the holder via a large threaded collar which must be removed from behind.

IIRC, once the collar is removed, the gauge slides out. The wires connected to it are in a jack which can be disconnected. The other end goes to the RJ45-type jack on the shunt.

[mikejeane]

Thanks for the help. I can't get to the attachment sleeve to unscrew it since I can't get behind the wall panel. There is no plate on the front with screws so that doesn't work either. The service lady with Dynamax says that I can just gently pry the round meter off, but nothing gives, so I presume the sleeve is on the back side. They should have mounted it from the front with the plate and screws. Everything else on that panel is mounted with screws--slide control, leveler control, usb port.

Anyway, I will put it on the list for the dealer.