juno2109 Posted May 17, 2012 Report Share Posted May 17, 2012 can show me a diagram of how to connect the fuel sending unit to the gauge thanks! Quote Link to comment
datzenmike Posted May 17, 2012 Report Share Posted May 17, 2012 One side of the sending unit is a black wire. This black wire must be grounded or go to a good ground. The other wire is a YELLOW wire that joins the truck harness and enters the cab under the pass side seat where it connects to the cab harness. From there it travels up behind the dash to the instrument cluster and is the #9 wire (still YELLOW) on the round plastic plug on the back. Now if your gas gauge is simply not working .... 1/ Ground the YELLOW wire and it should read FULL. If it does then the problem is either the tank sender or the ground wire. 2/ Does the TEMP gauge work? If both gauges do not work, the problem is likely the small voltage regulator that supplies both and not the gauges at all. Quote Link to comment
danzo620 Posted May 18, 2012 Report Share Posted May 18, 2012 datzenmike to the rescue again Quote Link to comment
juno2109 Posted May 18, 2012 Author Report Share Posted May 18, 2012 thanks bro! Quote Link to comment
Cardinal Grammeter Posted November 16, 2015 Report Share Posted November 16, 2015 First, the Temp gauge works (a miracle, yes I know) I put 5 gal in mine and the fuel gauge is on E. That is, it moved up to E. I have done no diagnostics because I am pushing to getting on the road after buying this project 1.5 years ago. What typically fails? Wiring connectors? this truck had massive failures from wiring corrosion: alternator, VR, horn contacts, wiper switch to list some.Sending unit itself:float arm pivot freezes? resistor wire breaks and unwinds? resistor wiper arm fails? resistor wire/wiper poor electrical contact? poor sending unit internal electrical connections? ? Any failure in the sending unit itself, there is a 99% chance I can repair it. But dropping the tank to get at it is NOT something I want to do. Maybe shoot some white vinegar on the top of the tank and hope for the best? haha But considering all the corruption done to this truck, who knows what the monkeys did to the wiring itself. EDIT: Is it possible to reach above the tank and touch the sending unit? Can I wiggle the electrical connections? (Of course now this is going to be a Grand Mess since I loaded the underneath up with the Chevron Marine Rust Proof Compound L discontinued in the USA but still sold by Michigan Petroleum Technologies.) Quote Link to comment
datzenmike Posted November 16, 2015 Report Share Posted November 16, 2015 External mount near rear wheels collects wet and mud on top of tank. Connections are at risk for corrosion. Next the tank seams can rust and leak. Had this and was able to solder it up. Almost any hole or poor hose can let crap in and rust inside. Had a gummed up (varnish) sender from siting and the gas evaporating. Had a dent that pushed up the sender and the pick up tube so gauge wouldn't go below 1/4 empty but it would run out of gas Quote Link to comment
Cardinal Grammeter Posted November 16, 2015 Report Share Posted November 16, 2015 Rats, there are vent nipples that have no hoses on them. I really don't want to drop that tank. Can I get my hand to the sending unit connectors? Quote Link to comment
datzenmike Posted November 17, 2015 Report Share Posted November 17, 2015 First, the Temp gauge works (a miracle, yes I know) I put 5 gal in mine and the fuel gauge is on E. That is, it moved up to E. This would indicate to me that it was stored empty with the sender down at the bottom. When 5 gallons (almost half a tank) was added the sender only moved up slightly. I had a sender like this covered in varnish, basically glued. I cleaned and gently worked it up and down a little at a time to not bend the arm and got it working but it will have to come out. Possibly gash sloshing around may loosen it, maybe.... Quote Link to comment
Cardinal Grammeter Posted November 24, 2015 Report Share Posted November 24, 2015 Just backing it out into you hard freed up the sending unit! So all is well. Quote Link to comment
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