85blueox Posted April 11 Author Share Posted April 11 What is the problem that made you want a switch? The gauge is switched by the valve (diagram above) If you can't switch tanks, it's the valve. If the gauge doesn't read on one side it's the wiring after the valve The problem is that the gauge shows empty and does not move. Switch has power and seems to work fine, have power at the valve. It has fuel by shows empty and does not move when the switch is selected from front to back. Link to comment Share on other sites More sharing options...
85blueox Posted April 11 Author Share Posted April 11 What is the problem that made you want a switch? The gauge is switched by the valve (diagram above) If you can't switch tanks, it's the valve. If the gauge doesn't read on one side it's the wiring after the valve I can check the grounds, where are the selector tank/sending units ground at on the truck? Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted April 11 Share Posted April 11 I can check the grounds, where are the selector tank/sending units ground at on the truck? Look at the diagram G105 & G701. There's TWO paths to ground! So while I doubt ground is a problem, you need to look in the front of the appropriate EVTM here on the site. Maybe someone else has the time to show you..... Link to comment Share on other sites More sharing options...
mat in tn Posted April 11 Share Posted April 11 I can check the grounds, where are the selector tank/sending units ground at on the truck? remove the radio and there is aground just inside the opening towards the glove box on the steel dash skeleton. but are the oil and temp gauges working? they share the same voltage supply. although they each ground at the engine block. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted April 11 Share Posted April 11 remove the radio and there is aground just inside the opening towards the glove box on the steel dash skeleton. but are the oil and temp gauges working? they share the same voltage supply. although they each ground at the engine block. 701 handles a LOT of "stuff" You'd notice if it was gone. Link to comment Share on other sites More sharing options...
mat in tn Posted April 11 Share Posted April 11 701 handles a LOT of "stuff" You'd notice if it was gone. have you proven the gauge independently? Link to comment Share on other sites More sharing options...
85blueox Posted April 11 Author Share Posted April 11 have you proven the gauge independently? My other gages work fine. Link to comment Share on other sites More sharing options...
85blueox Posted April 11 Author Share Posted April 11 have you proven the gauge independently? I did see on the diagram where G701 is grounded, but it shows for the diesel that I have it has a ground on G105 and it does not show where it is grounded. I would think back on the frame somewhere. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted April 11 Share Posted April 11 I did see on the diagram where G701 is grounded, but it shows for the diesel that I have it has a ground on G105 and it does not show where it is grounded. I would think back on the frame somewhere. Go look at the EVTM, in the front, all the grounds are shown.... But I don't think it's a ground. I think you have a crudded up connector under the truck. Link to comment Share on other sites More sharing options...
viven44 Posted April 12 Share Posted April 12 The problem is that the gauge shows empty and does not move. Switch has power and seems to work fine, have power at the valve. It has fuel by shows empty and does not move when the switch is selected from front to back. Process of elimination Unplug the harness at the selector valve on the frame. Jump pins 3 and 4 or 5 and 4. It will bypass anything and everything and should connect front or rear sender respectively to fuel gauge depending on which pins you Jump. If that doesn't work either, definitely something with grounds, gauge itself, etc Link to comment Share on other sites More sharing options...
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