Another Fuel Gauge Problem????? HELP!!!!

[70396CST10]

Well, This is driving me crazy..

I have been trying to get my fuel gauge working with no luck.. The guy I bought the truck from said it just needed the float replace..

So I buy a new float and install it.. Nope, does not fix the problem and yes, the float did float...

So I pull the wire off the sender and it goes to the 3 o'clock position so that is good..

Then I ground the wire and it goes to empty and that is good..

Next I check the fuse and that is good..

Then I check the ground wire on the fuel gauge itself and that is good..

Then I try grounding the sending unit and that makes no change.. And yes, I checked the float after installing it by removing it and putting it in water.. No luck..

So then I order a new sending unit and that does fix the problem..

So then I take a fuel gauge I have from my 69 camaro and take the resistor off it and change the resistor and that did nothing..

Gauge is stuck right at about the 1/8 mark..

I have about 6 gallons of gas in the tank..

I tried manually moving the sending out of the tank with it grounded and hooked to the brown wire and it will go just past 1/4 tank with the arm all the way up??

How should the wiring be on the back of the fuel gauge.. I have 3 posts.. Bottom post is grounded to the cab.. Top 2 posts have the resistor and circuit board attached to them..

I am at a loss.. I have tried everything the board research has showed me with no luck.. So far I have a new float, new sending unit and no worky gauge..

Very frustrated and aggravated with this gauge not working after all the wasted time put into it..

Can someone explain how the back of the gauge works?

I assume 12 volts into one side and the resistance is on the other side with a ground on bottom???

Thanks for any help..

James..

[JimKshortstep4x4]

With the tests that you have done, it sounds like the wiring is correct. Two items that I would suggest checking is the ohm reading of the the tank unit, (0 ohms to 90 ohms). The other item is the resistor that you put on the dash gauge. With a 1/8 th tank reading, it still sounds like a resistor problem.

Jim

[byrd]

Jim I totally agrree with you, and was going to suggest the same thing. There are two sending units, 30 ohm and 90 ohm, yours should be a 90 ohm.
I have a bunch of the resistors here if you find that you need one I could get a known good one to you for $10 shipped...Randy

[70396CST10]

Thanks Jim and Byrd...

The 69 camaro fuel gauge worked excellent in my car and I assumed all the GM resistors were the same? The only differences I noticed is that the truck resisitor is thicker in shape and has orange on one side and nothing on the other.. The camaro resistor is thinner and has white and looks like windings around it...

The sending unit came from Year one and is suppose to be a V8 sending unit for a 70 model C10 pickup????

The sending unit I removed read a little higher on the gauge but very close and had 90 ohms stamped in it..

I will try and do the ohm reading with the sending unit removed again..

Byrd: How would I go about getting a resistor from you?

Thanks..

James..

[byrd]

PM returned....Randy

[70396CST10]

Thanks byrd....

I sent you the money through paypal..

I hope this fixes my problem..

I will post up the results when I get the resistor hopefully sometime next week..

Thanks again..

James..

[70396CST10]

I filled the tank up Friday and the gauge would just read between a 1/4 and 1/2 a tank..

Installed the new resistor from Randy.. Thanks Randy..

And now the gauge is reading past full.. I drove the truck this morning and the gauge moved some so I will say the resistor fixed the gauge problem.. Wasn't the sending unit..

So for the record and research..

Resistor was the problem...

Thanks for all the help guys..

James..

[byrd]

Glad it all worked out for you. My truck also reads past full when I fill it up, but not for very long

[KFreddy]

Hi all,

I've had the same issue with my fuel gauge, reads between 1/4 and 1/2 all the time, and have also taken the same trying to fix it steps as James did. I'm curious that my issues may be the same as his, the resistor. Does someone have a picture of the resistor or a part #, ie radio shack or is this just a straight up 90ohm resistor?

Thanks,

-Fred

[70396CST10]

Hey Fred,

This is how my gauge would work..

with a full tank or half a tank it would not read anymore than between 1/4 to 1/2 tank of gas..

my gauge would work when it would get down on empty.. Just would not go higher than between 1/4 to 1/2 a tank..

Good luck with you problem... Randy can help you and many others, they solved my problem..

James..

[8696steve]

Is there a part number on the resistor? I am having the same problem with my fuel gauge. Any help would be great.
Steve

[byrd]

Here you look here middle of the page. I do not have any for sale right now..
http://www.truckandcarshop.com/trucks60_72/t60_078.html