Community Forums

Dave Packard · 03-21-2015, 09:13 PM

Hey guys, I am new to this forum and am I ever glad to find this forum. My wife and I are 13 months new full timers to the RV lifestyle and are learning as we go.http://www.irv2.com/forums/images/smilies/thumb.gif

After reading this forums post on fuel gauges and grounds, I think that might be my trouble and will be digging into that tomorrow morning. Thank you folks very much for this tip.

Below is what I wrote to explain the trouble I am having with the fuel gauge.
We have a 2004 Fleetwood Discovery 39s motorhome diesel pusher.
I drove to the fuel station, about 10 miles away from our resort here in Port Saint Lucie Florida, and filled it up 2 weeks ago. The fuel gauge read full after that time.

I then drove it back to the resort and did not start it up again until yesterday only to find that the fuel gauge was not working.
It is reading empty, I know that’s incorrect because we have not driven it that far, just 10 miles since fueling it up.

What I do notice is that when I turn on the ignition the fuel gauge needle does wiggle a little but that’s it.
I am thinking a few things, the gauge could be broken, or the fuel sensor is not working properly, or maybe there is a fuse someplace that's blown. I checked all the fuses on the 24 volt system that I could find and they are ok.
Can you possibly give me any information on this problem?
My wife and I are going on another road trip in 3 weeks ( on April 15 ) and I want to get this taken care of asap.

**TonyDi** · 03-21-2015, 09:51 PM

Glad to have you here withh us.

My best guess is the sending unit has gone bad, or you have a faulty ground.
You can make a jumper with some wire and a couple of alligator clips. Try grounding the gauge, then the sending unit, and see if there is a difference in the reading. Someone else may have additional suggestions.

Hopefully it's not a bad sending unit.

Good luck!

mchero · 03-21-2015, 10:47 PM

Going to have to drop the fuel tank to get to the sending unit. Hmmm, if you had a Silverleaf setup you could see if the sending unit was indeed the issue.

Welcome to the forum, we have an 07 39V & love it.

Dave Packard · 03-23-2015, 07:33 PM

I found the fuel gauge to be defective. I can order one from Freightliner at a cost of $316.00 Wow what a rip off considering the average gauge I find in the auto stores are around $35.00.
I ordered one from NAPA for $35.00 and I am hoping it has 4 pins on the back. I will be able to work with that. If not then it's a call to Freightliner unless anyone out there knows of a better idea?

Dave Packard · 03-23-2015, 07:34 PM

Quote:

Originally Posted by mchero

Going to have to drop the fuel tank to get to the sending unit. Hmmm, if you had a Silverleaf setup you could see if the sending unit was indeed the issue.

Welcome to the forum, we have an 07 39V & love it.

I found the fuel gauge to be defective. I can order one from Freightliner at a cost of $316.00 Wow what a rip off considering the average gauge I find in the auto stores are around $35.00.
I ordered one from NAPA for $35.00 and I am hoping it has 4 pins on the back. I will be able to work with that. If not then it's a call to Freightliner unless anyone out there knows of a better idea?

mchero · 03-23-2015, 09:44 PM

Can you take a picture of the gauge?

LouieL · 03-23-2015, 10:41 PM

Dave, How did you come to the conclusion the gauge was bad? Also what type of replacement gauge did you order for the parts store? If you ordered a universal replacement you find they only have 3 wires (12v, neg, and signal in)

Dave Packard · 03-25-2015, 05:47 PM

Quote:

Originally Posted by LouieL

Dave, How did you come to the conclusion the gauge was bad? Also what type of replacement gauge did you order for the parts store? If you ordered a universal replacement you find they only have 3 wires (12v, neg, and signal in)

Louie,
Well I guess I don't know as much about these repairs as I thought I would . I tested the incoming voltage from the sending unit when I turned the key on I get around 6.4 volts. I thought that was a meaning of a good sending unit. But now I am thinking you guys are right about the sending unit being bad.
The reason is that when I turn on the ignition I notice the idiot light on the dash comes on reading that I am low or empty on the fuel. To me, that would tell me that my sending unit float must be on the bottom of the tank or it is just plainly bad. and needs to be replaced.
Also, after reading on about the current flow to the fuel gauge, I learned that it works in conjunction with the lower or higher resistance of ohms coming from the fuel tank sending unit. The gauge and sending unit have to be matched up with the same ohms or else you will get incorrect level reading on the gauge. So when buying a fuel gauge it is really important to know the correct ohms on both the gauge and sending unit.
I will put the dash back together tomorrow morning.
I know I have a full tank of diesel and I get 9 miles per gallon so I will just watch my mileage and fuel up at the right milage so I won't run out. When we get home our coach is going in for some service and this will be on the list as well.
Thanks for all your input gentleman. I have learned alot.
One guy here at the resort told me that if you own a motorhome you must have an invisible sign on your forehead that says RICH MOTOR HOME OWNER. LOL.
So it looks like Freightliner will get $316.00 plus shipping from me for a new fuel gauge.
Dave Packard

Dave Packard · 03-25-2015, 06:13 PM

Quote:

Originally Posted by mchero

Can you take a picture of the gauge?

Mchero,
Here are 4 pictures of the gauge I removed from my dashboard. Any thoughts about it?
Dave Packard

mchero · 03-25-2015, 07:54 PM

Quote:

Originally Posted by Dave Packard

Mchero,
Here are 4 pictures of the gauge I removed from my dashboard. Any thoughts about it?
Dave Packard

Dave, Looking at the tag on the top PIC it appears to be a Borg Warner fuel gauge.

My 93 Pace had Isspro gauges so I do know that Isspro was one source....Let me do some digging...

Oh, on my 07 Discovery I was dinking around with the diagnostics on the dash and ran across the gauge test. I selected it & I was able to set each gauge on the dash to 50%! was real cool! Did it while at idle!

If you do end up replacing the sender make sure your tank it not topped off!

SLOWLY warming up here in the N.E. Days are starting to hold above freezing. Another week or so of freezing night temps!!

RAWHIDE!
http://www.ebay.com.my/itm/Medallion...-/261629596158

Dave Packard · 03-26-2015, 02:48 PM

Quote:

Originally Posted by mchero

Going to have to drop the fuel tank to get to the sending unit. Hmmm, if you had a Silverleaf setup you could see if the sending unit was indeed the issue.

Welcome to the forum, we have an 07 39V & love it.

You may very well be right about dropping the fuel tank. Hey, what is a "Silverleaf setup" ?

mchero · 03-26-2015, 05:57 PM

Quote:

Originally Posted by Dave Packard

You may very well be right about dropping the fuel tank. Hey, what is a "Silverleaf setup" ?

My 07 Discovery has a J1939-equipped engine. Their is a black 9 pin port port under the dash & another one at the rear of the coach. I just ordered a wireless unit that I'll install under the dash. It plugs in to the port under the dash.
Once installed I can get all data from both the engine and Allison transmission. I "almost" went with the pressure pro option but that would be an additional $600 after purchasing the reciever & 10 tire sensors at $50/pop!

Here's the site
http://www.silverleafelectronics.com/?q=node/6

stink · 03-26-2015, 11:40 PM

Your fuel level is going thru the vdc. This is a serial data transfer setup that has all guage data going thru a serial buss. The vdc on my coach is in the rt rear storage bay second from the end behind rear axle. The enunciator panel, the light panel on the dash separates the data to each guage. Most likely your guage problem is in the vdc and not the guage. Please do not try to wire an aftermarket guage to the serial wiring going to the fuel guage. You can swap any guage to the fuel guage location to see if your guage is defective as the other guage plugged into the fuel guage plug will show fuel level. If not try wrapping the vdc with a screwdriver handle while someone watches the guage. If it wiggles or moves you need the vdc.
You said the guage "wiggles" when you turn on the ignition and this is normal as the light panel computer and the vdc and guages "sync". Pm me if you need more help