I just bought this truck yesterday,a 1996 ext.cab 2500 diesel....
the fuel gauge doesn't work. Full tank of fuel....no work, drove 150 miles...still no work at all.
Before I dig, I thought I would begin here and ask you guys if there is a "USUAL" problem (if any) to look for.
Thanks.................
GCSS[roll

 

Fuel level sender in the tank more than likely.

 

agreed. fuel sending unit and float. common failure.

 

As the other have said, fuel level sender, most will strike.


Part number is 4797738, mid fourties at most internet parts dealers, I use Moparpartsamerica.com

art Number: 4797738 List Price Core Price Your Price

Electrical - Chassis electrical - Senders - Fuel gauge sending unit FUEL GAUGE SENDING UNIT, All Models, Diesel Engine 1997
$66.85 $0.00 $44.51

Good luck!

 

Thanks guys...
Is there a way to determine it by testing /probing the wires FIRST?
I like to diagnose it if possible

 

Buy a factory service manual here and it will explain how to test many things in great detail. http://www.genosgarage.com/products.asp?dept=17

 

If the float is ok (unlike the old one in the above picture) you can rebuild your existing one with some minor work. Had to replace mine every 2 years- got tired of it. Several suggested methods on how on various sights... basics, replace the pivot with a screw and washers because the plastic wears away and allows the arm to rock on the pivot creating a poor contact/no contact situation on the rheostat contacts this no reading or weird readings.

Easy rebuild, not so easy change- lift the bed or drop the tank. Tank drop is much easier IMHO - done it several times now.

 

Well looks like I may do the tank drop.....I will try to run it low so it isn't too heavy.
Interesting.... I ran the VIN#s on the truck and it was puchased new by.....CUMMINS!....
That explains the stuff on it....jake brake (with a cummins P/N,and an AFR exhaust along with a Cummins cold air intake....don't know what else they did.....

 

take the wire off the sending unit on the tank top and rig test wire directly to ground, (from the wire running to the sending unit). If the gauge goes right to full with the ignition on, it is your sender most likely as the rest of the system is working, if not, look further before dropping the tank. I'd like to be sure before dropping the tank and this test will give piece of mind that it is the sender. All that being said these trucks are notorious for bad senders.

 

That's because the circuit board that the windings are wrapped around wasn't compatible with diesel fuel and somewhat melted.
Dodge finally figured it out in 2002 and changed the material.
Replacements are made with the new material.
Not worth it in my opinion trying to repair a pre '02 sender.

 

exactly. ground the tank wire. it will peg the fuel guage to 100% if the circuit is good. if it does the sender is culprit.

and like was mensioned if the float is deteriorated at all. change it. or it will get saturated with fuel and it doesn't float at all anymore.

 

this is what I needed!
Thanks a bunch guys!
I'll check it tomorrow and keep y'all posted!
Dave

 

I tested it as you said...the gauge climbs when I grounded it out.
sender is bad!
Thanks guys!

 

I'm far from an expert, but I've never heard of the circuit material on the board degrading- every failure I've ever read, heard of, or seen has been due to the plastic pivot on the arm.

Remember most but not all trucks have an anti syphon ball valve in the fill tube. I used a chemical fluid pump but any old diesel capable electric fuel pump can be used to drain the tank. Last time I had to drop mine I had just filled it the day before the problem (break line burst behind the tank). Pull the lines off the tank and use the supply fitting to hook to the pump for draining.
I used a section of regular fuel line for the hose on both sides of the pump- run isopropal alcohol through the fuel line after finishing to clean or toss it. Don't really understand the chemestry but the alcohol "washed" out the diesel and has kept the non diesel rated line from rotting.

 

I checked with my parts guy at the local Chrysel dealer and the new sending unit from Ma Mopar is $50.02......
I have been rapping on the tank and kinda watching the trip-odometer vs fuel mileage and I am leaning towards dropping the tank. I have not ruled out unbolting the box and just tilting it up enough to allow clearance. I'll think on it a bit.