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Mjw2347 · 05-11-2022, 08:42 PM

Just put in two new starter batteries and the coach starts up and runs just fine. However, the dash “low volts” battery light came on and none of the dashboard gauges (instrument cluster) work except for the fuel gauge. I took the coach out for a test drive and it runs just fine. I checked all of the fuses in the battery compartment, the battery cables/connections and on/off switches and they are good to go but there is definitely a short to the dashboard gauges or some other electrical connection problem. In addition, we checked the alternator and it is charging the batteries according to the Victron. In addition, the Vansco lights up as it did before the old starter batteries died. I’m a novice on mobile electronics and would appreciate some HELP on this issue… Thanks!

Arch Hoagland · 05-11-2022, 09:07 PM

Have you put a voltmeter directly on the batteries?

I suggest doing that with the engine running and then with the engine shut off.

paul65k · 05-12-2022, 09:22 AM

Quote:

Originally Posted by Arch Hoagland

Have you put a voltmeter directly on the batteries?

I suggest doing that with the engine running and then with the engine shut off.

I was helping Max yesterday and the starting batteries were at 12.8 resting and 13.9V running as measured on the Victron battery manager.

It would appear that the batteries are getting voltage from the alternator but not being recognized at the ECU or other gauges/warning light. There is no output at either of the ECU data ports in either the front or rear as measured by the BlueFire adapter

We checked the 4 fuses labeled ECU in the battery bay area........ this is is kinda weird because this seemed to crop up after changing out the starting batteries only

Kid Gloves · 05-12-2022, 09:54 AM

Assuming that all wiring was properly reconnected, has a VMM reset been performed? Off for 30 seconds and then back on.

Mjw2347 · 05-12-2022, 10:43 AM

All,
Update — I reconnected the new chassis batteries a few minutes ago and tested them with engine off and it read 12.84V. I started the engine and believe it or not everything seems to working just fine. The batteries show 14.09V with the engine running and no “low voltage” warning light. We are back in business with all gauges working properly. I’m assuming the VMM reset itself thus correcting the readout issue. Regardless, I’m thankful now that everything is back to normal. Thanks to those of you who weighed in on my electrical issue. Especially Engineer Mike, Sandy and Paul Bruce — a special note of appreciation for walking me through the initial diagnosis… Looks like the Alpine/VMM angel fixed the problem overnight… We’re ready to hit the road. Cheers!

Mjw2347 · 05-12-2022, 12:14 PM

One additional observation — I have a BlueFire diagnostic device on the data port below the Vansco on the passenger side of the front dash. I removed the BlueFire and noticed the “low voltage” dash warning light turned off and the instrument cluster/gauges started working. I’m now thinking the BlueFire (which has not been updated for a couple of years) might have been the problem…
-Max