85blueox Posted February 15 Share Posted February 15 I have an 85 F350 diesel with duel tanks. Fuel switch is on the heater/aircont. box/consule. both gauges show 0 even when I add fuel, been that way since I aquired it a year and a half ago. If you experts had to guess, where do you think the problem is? Just looking for a starting point. Since it shows 0 fuel on both tanks I thought maybe the switch, wires, possible the gauge is the problem. Knowing the wires are always a mess on things thanks to 30 years of crazyness I though it might be the problem. Link to comment Share on other sites More sharing options...
Gary Lewis Posted February 15 Share Posted February 15 We have a page at Documentation/Electrical/Gauges that might help. On the Troubleshooting tab is the suggestion to pull the wire off the sending unit and ground it - with the switch pointing to the tank of course. Turn the key on and the gauge should go to Full. On the Gauge Circuits & Spec's tab there's a schematic of the wiring and you can click it to make it bigger. But to easily see it go to Documentation/Electrical/EVTM/1985 EVTM and then scroll down to Fuel Tank Selector & Gauges (Diesel). There you'll see that the Y/W wire goes from the switch to the gauge, so if you were to ground it the gauge should peg as well. Link to comment Share on other sites More sharing options...
viven44 Posted February 16 Share Posted February 16 We have a page at Documentation/Electrical/Gauges that might help. On the Troubleshooting tab is the suggestion to pull the wire off the sending unit and ground it - with the switch pointing to the tank of course. Turn the key on and the gauge should go to Full. On the Gauge Circuits & Spec's tab there's a schematic of the wiring and you can click it to make it bigger. But to easily see it go to Documentation/Electrical/EVTM/1985 EVTM and then scroll down to Fuel Tank Selector & Gauges (Diesel). There you'll see that the Y/W wire goes from the switch to the gauge, so if you were to ground it the gauge should peg as well. For the diesel (same as 460), I believe the Y/W wire goes from the on-frame selector valve harness to the gauge. (Pin 4 on the harness.) Grounding pin 4 Y/W on that harness should make the gauge go full, if it doesn't then I think its likely the gauge or connection to the gauge on the printed circuit board. Link to comment Share on other sites More sharing options...
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