VMS 645 Glass Dash Fuel Guage

I have a VMS 645 glass dash on a 2005 Allegro Bus.

Two questions:

First a minor one. The transmission mode symbol shows as a half circle showing only half of the M. The VMS manual describes this symbol as a full circle.

The main point of this email deals with the VMS fuel gauge. Starting with a full tank I show one half tank (50%) after only 285 miles at 9 MPG. After 460 miles I was at 25%.

On another trip the Freight Liner LCD Information Center showed a low fuel alert (10%) after traveling 482 miles after a fill up. I don't recall the VMS reading in this case. I was fairly sure I was not that low but filled in any case. 56 gallons filled it up. I'm not sure if the Freight Liner LCD is still receiving the proper info after the Glass Dash install.

I never noticed any problems with the old analog fuel gauge. Our fuel tank is rated as 150 gallons. I'm guessing that even when I fill up I may not be have a full 150 gallons in the tank so I rated the tank at 140 gallons. Should I tell the VMS a number other than 150?

Here's what my Fuel Tank config looks like.

Size: 140
Sensor Type: 240-33 OHM
Sensor Port: 3 - Fuel
Tank Level: 22%
Current Counts: 470
Empty Counts: 545
Full Counts: 210

Thanks for your help.

re: Glass dash in your bus

Hello Skip

First, we need to dial in which dash model is installed. You called it a VMS645--which is the current model...but when I asked Dale for some help on this he said otherwise. Could this be a VMS616? That will be important for addressing the Half-M problem.

Also, we'll need the SW version its running to see if an update maybe addressed this. I believe that there's a special key-press combo that will reveal this:
Hold down the to two buttons and wait a couple moments--then let up. A setup screen should appear with that SoftWare version, such as 30CD04 or 10xx03 .

Could you summarize the fuel issue in 5 words? The numbers are helpful once I get an idea of what looks wrong...but I'd have to start making a table and do some guessing--just to cipher what the crux of the issue.

Wrong rate...proportions...starting point/ expected endpoint?

As for the 150 v 140: Yes. A tank 'rated' at 150 should be plugged in as a number that reflects the real drop-dead fill up point. Which as you know is *not* empty. Most folks plug in 140 or 145 in this case.


Art Renda
Documentation Central,
Silverleaf Electronics
(888) 741-0259

Glass Dash Fuel Problem

I will get you the info you asked for in a week or so as I am not with the RV at this time.

VMS 645 vs. VMS 616

What are the differences between the VMS645 and the VMS616?

Glass Dash Fuel Readings

Hello Art,

Here are the specifics on my Glass Dash.
BIOS: VMS 645/650
ecos Version 1.15
July 24, 2013

Hardware: VMS 645 Rev 3

Free Heap: 14810212
VMS Version: 11cc11

Problem: VMS indicates 1/4 tank - after traveling 460 miles from full tank. Took 54 gallons to fill. Wrong rate?

Transmission mode symbol shows only a half circle and half of the M.

Thanks, Skip