Fuel gauge not reading correct.

[Dale Malquist]

fuel gauge is way off. I have the coach at a local rv repair and they are waiting for help from Beaver Coach sale.  They think the sensors on the tank are ok and the problem is in the instrument cluster.
sure I'm not the first with this problem.

[Steve Huber Co-Admin]

For more info, search Fuel Gauge. Relatively common problem. Let us know what they find /do in any case.
Steve

[Scott Shearer]

Dale,

Might be wrong, but I believe that your 2007 Contessa has the Medallion digital instrument cluster. Manuals for the Medallion systems are located in Coach Assist-> Electrical Systems…->Electronic Dash (Medallion) Manuals.

Both “M2” and “M3" service manuals contain images that should help determine if your coach does use the Medallion system. Look at page 6 in the M2 service manual or page 10 in the M3 service manual.

Scott

[Steve Huber Co-Admin]

Dale,
Check the ground connection at the fuel sensor  at the tank. If there is more than a 3 ohm difference between the tank and battery ground the gauge will malfunction. See ppg 4 and 9 in the M2 manual that Scott referred to.

(I suspect the 07 Contessas have the M2 system as the M3 dwgs are dated in late 06 so only late 07 builds probably have the M3 system).
Steve

[Dale Malquist]

Finally they have given up. Blaming the gauge.

[Dale Malquist]

Picked up the coach after I told them to forget about the fuel gauge. They are blaming the gauge and instrument cluster? Ill have to attempt repair myself so I have some questions.
Where is the ground located on the tank?
I assume there is a set voltage going to the (sender) at the tank. Then the return voltage is determined by the resistance of the sender. If correct can I read a lower voltage at the gauge. I must be off because I can’t account for the third wire discounting the ground.
Also the two air pressure NOW don’t work. The air pressure alarm quits when air pressure is high enough.

[Carl Boger]

Dale,

I would look at the ground coming to your dash controls.  Usually they are daisy chained to several of the gauges.  You can also add a 2nd ground wire to the gauges to improve the grounding situation, or just as a test to see if the ground is  the problem .  Just run a new wire to the electrical bay grounding block up to where the gauges start to be daisy chained together.  I am not sure which sending unit you have, I believe my sending unit only has 2 wires going to it.

[Dale Malquist]

Firstly to the forum I did not clearly or adequately state the problem. My fault.
My fuel gauge would never read full but under seven eights when fully topped  off. When it would get to the empty mark there would still be fifty or sixty gallons left.

After reading many of the fuel gauge posts (my head is spinning) I didn’t see anything about a problem like mine. What I’m going to do is try to get the gauges back to where they were when I took it in for service. Then try and troubleshoot it .

I may have caused the problem myself by tilting the coach to get in an extra 20 or30 gallons.

[Dale Malquist]

They ordered a new instrument computer from Medallion. That apparently got everthing working again, however, the fuel gauge reads just over 7/8 full when I fueled uo before they did the work.

[Fred Cook]

Last year I had a leak above my fuel tank and the repair shop lowered the tank to repair it. Well, after that the fuel gauge went erratic and was never right. I called the repair shop and they were not sure what the problem was. So I looked under there and found a ground wire hanging down around the tank. I connected it back to the chassis and it has worked perfectly ever since.