ArdWrknTrk Posted August 26, 2020 Share Posted August 26, 2020 Yes the connector to the Inertia switch has power in "run". Having trouble finding the Fuel tank selector relay, in the EVTM it says it should be under the dash, but cant see it. Right at the other side of the firewall, LH side at the engine compartment there is a green and grey relay. the engine mounted fuel pump has been spliced into the red wire going to from the green relay, could the green one be the Fuel tank selector relay? /Christian Yes... yes it could, and is (in a stock truck) Link to comment Share on other sites More sharing options...
Gary Lewis Posted August 26, 2020 Share Posted August 26, 2020 Ok You want me to check power to inertia switch and relay behind EGR valve. But at the connector to the valve switch there was power in "run" and front tank selected. With rear tank selected, no power in any of the 5 wires. from the top 1. wire is Yellow/blue band-no light 2.wire is white -blinking light 3. wire is blue/green-no light 4.wire is bli/white-continious light 5.wire is red-no light Gary, your right off course. But I would rather like to try keeping the two tanks since it was born with it. Best Christian From the wire colors you mentioned I think yours is wired the way the 1985 EVTM shows, and the schematics are below. I assume that the information you gave with power on some wires in "run" was with the switch in the front position. Correct? But was the engine running? 1. wire is Yellow/blue band-no light: This should be the wire to the rear sending unit and shouldn't have any power in Front 2.wire is white -blinking light: This is surely the yellow/white wire from the gauge, and the blinking is due to the instrument cluster voltage regulator. This is correct. 3. wire is blue/green-no light: Could this be the dark blue/yellow wire? If so it should have blinking power on it. 4.wire is bli/white-continious light: If this is brown/white it should have continuous power in Front 5.wire is red-no light: This is probably orange, and it should be grounded in Front So, with no power on any of the wires in Rear, either your tank switching valve is bad or the fuel tank selector switch in the cab is bad. Test the switch in the cab to see. Link to comment Share on other sites More sharing options...
Papelione Posted August 26, 2020 Author Share Posted August 26, 2020 From the wire colors you mentioned I think yours is wired the way the 1985 EVTM shows, and the schematics are below. I assume that the information you gave with power on some wires in "run" was with the switch in the front position. Correct? But was the engine running? 1. wire is Yellow/blue band-no light: This should be the wire to the rear sending unit and shouldn't have any power in Front 2.wire is white -blinking light: This is surely the yellow/white wire from the gauge, and the blinking is due to the instrument cluster voltage regulator. This is correct. 3. wire is blue/green-no light: Could this be the dark blue/yellow wire? If so it should have blinking power on it. 4.wire is bli/white-continious light: If this is brown/white it should have continuous power in Front 5.wire is red-no light: This is probably orange, and it should be grounded in Front So, with no power on any of the wires in Rear, either your tank switching valve is bad or the fuel tank selector switch in the cab is bad. Test the switch in the cab to see. Ok Rechecked the relays, actually the one that is spliced into is the grey one sitting besides the green relay. The grey one has power on the small terminals in "run", and relay clicks on 12 v added to small terminals on the relay itself. So Inertia switch gets power, and Fuel tank selector switch relay checks out ok. what would you do for next step? Link to comment Share on other sites More sharing options...
Gary Lewis Posted August 26, 2020 Share Posted August 26, 2020 Ok Rechecked the relays, actually the one that is spliced into is the grey one sitting besides the green relay. The grey one has power on the small terminals in "run", and relay clicks on 12 v added to small terminals on the relay itself. So Inertia switch gets power, and Fuel tank selector switch relay checks out ok. what would you do for next step? You have several things that aren't right and each them require testing. So lets start at the beginning. First, you have an add-on fuel pump. Why? Is it because the rear tank's pump doesn't work? Or the front tank's pump doesn't work? Or both? But the rear tank's pump can't work if the tank selector valve isn't working. And you said there's not power on the connector to the tank selector valve in Rear. I assume that's with the connector on the valve, right? If there is no power to the valve then you need to test the switch in the cab. Make sure it is working properly. Then, if it is working properly, test the signals to the tank selector relay. But, you said " the one that is spliced into is the grey one sitting besides the green relay". Spliced in isn't right. There should be nothing "spliced in". So, can you show us a picture of the "splicing"? Link to comment Share on other sites More sharing options...
Papelione Posted August 26, 2020 Author Share Posted August 26, 2020 You have several things that aren't right and each them require testing. So lets start at the beginning. First, you have an add-on fuel pump. Why? Is it because the rear tank's pump doesn't work? Or the front tank's pump doesn't work? Or both? But the rear tank's pump can't work if the tank selector valve isn't working. And you said there's not power on the connector to the tank selector valve in Rear. I assume that's with the connector on the valve, right? If there is no power to the valve then you need to test the switch in the cab. Make sure it is working properly. Then, if it is working properly, test the signals to the tank selector relay. But, you said " the one that is spliced into is the grey one sitting besides the green relay". Spliced in isn't right. There should be nothing "spliced in". So, can you show us a picture of the "splicing"? Hi You have several things that aren't right and each them require testing. So lets start at the beginning. First, you have an add-on fuel pump. Why? Is it because the rear tank's pump doesn't work? Or the front tank's pump doesn't work? Or both? I don't know, it was like this when I bought it, didn't´t get any explanation. But the rear tank's pump can't work if the tank selector valve isn't working. And you said there's not power on the connector to the tank selector valve in Rear. I assume that's with the connector on the valve, right? That is correct, power like previously described with switch in "front", no power with switch in "rear" If there is no power to the valve then you need to test the switch in the cab. Make sure it is working properly. Then, if it is working properly, test the signals to the tank selector relay. OK, will try and test the cab switch tonight. But, you said " the one that is spliced into is the grey one sitting besides the green relay". Spliced in isn't right. There should be nothing "spliced in". So, can you show us a picture of the "splicing"? Yes, like I wrote the two small terminals on the grey relay clicks and the connector shows power with key in "run", from this relay goes RED (spliced into from the add on fuel pump, Orange w blue stripe, pink w elk stripe, and black Shown here below The splice itself, large red wire I'm holding going to add on pump, rest of the wires going from grey relay to a connector and then under the truck. Lastly, here is the add on fuel pump, with a fuseabel(spelling) link and the large red wire that is spliced into the red from the grey relay. Does it make sense, happy to take more pictures. /Christian Link to comment Share on other sites More sharing options...
Gary Lewis Posted August 26, 2020 Share Posted August 26, 2020 You have several things that aren't right and each them require testing. So lets start at the beginning. First, you have an add-on fuel pump. Why? Is it because the rear tank's pump doesn't work? Or the front tank's pump doesn't work? Or both? But the rear tank's pump can't work if the tank selector valve isn't working. And you said there's not power on the connector to the tank selector valve in Rear. I assume that's with the connector on the valve, right? If there is no power to the valve then you need to test the switch in the cab. Make sure it is working properly. Then, if it is working properly, test the signals to the tank selector relay. But, you said " the one that is spliced into is the grey one sitting besides the green relay". Spliced in isn't right. There should be nothing "spliced in". So, can you show us a picture of the "splicing"? It sorta makes sense - they added a relay to run the added on fuel pump. But we need to decide what it is you want to do - continue with the added-on fuel pump or go back stock. We need to determine what shape the original wiring is in to help you make the decision. You should have two relays from the factory: The fuel pump cutoff relay and the tank selector relay. My fuel pump cutoff relay is the green one attached to the fender, shown below, and the tank selector relay is the gray one just to its left. We need to see if you have both of those and if they are wired correctly. The wiring is shown in the post above. If their wiring has been hacked then you will need to decide what you want to do - put the wiring back or stay with the added-on pump. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted August 26, 2020 Share Posted August 26, 2020 From the wire colors you mentioned I think yours is wired the way the 1985 EVTM shows, and the schematics are below. I assume that the information you gave with power on some wires in "run" was with the switch in the front position. Correct? But was the engine running? 1. wire is Yellow/blue band-no light: This should be the wire to the rear sending unit and shouldn't have any power in Front 2.wire is white -blinking light: This is surely the yellow/white wire from the gauge, and the blinking is due to the instrument cluster voltage regulator. This is correct. 3. wire is blue/green-no light: Could this be the dark blue/yellow wire? If so it should have blinking power on it. 4.wire is bli/white-continious light: If this is brown/white it should have continuous power in Front 5.wire is red-no light: This is probably orange, and it should be grounded in Front So, with no power on any of the wires in Rear, either your tank switching valve is bad or the fuel tank selector switch in the cab is bad. Test the switch in the cab to see. If the tank selector switch was open the selector relay should default to 'rear', yet Christian has the side tank registering fuel and obviously the switching valve is pulled in for that to happen. With the connector disconnected, which wire has continuity to (29) yl/wh at C-127? If it's y/lb, the sender portion is on the rear (correctly) If it's Y/DB the motor in the valve is stuck on the side tank. Link to comment Share on other sites More sharing options...
Papelione Posted August 26, 2020 Author Share Posted August 26, 2020 It sorta makes sense - they added a relay to run the added on fuel pump. But we need to decide what it is you want to do - continue with the added-on fuel pump or go back stock. We need to determine what shape the original wiring is in to help you make the decision. You should have two relays from the factory: The fuel pump cutoff relay and the tank selector relay. My fuel pump cutoff relay is the green one attached to the fender, shown below, and the tank selector relay is the gray one just to its left. We need to see if you have both of those and if they are wired correctly. The wiring is shown in the post above. If their wiring has been hacked then you will need to decide what you want to do - put the wiring back or stay with the added-on pump. I have a black plastic cover marked FORD with two relays in it, placed aproximately the same place as yours The green one (as in EVTM page 105) has a Y wire a R/Y, a BK but also a tan and a dark blue or purple with a stripe in it. It looks very stock and untouched, and should be fuel pump cutoff relay The grey has R, O/LB, PK/BK AND BR/W and should be tank selector relay, relay looks stock, but further down the add on has been spliced to the red. Sounds pretty good right? Link to comment Share on other sites More sharing options...
Gary Lewis Posted August 26, 2020 Share Posted August 26, 2020 I have a black plastic cover marked FORD with two relays in it, placed aproximately the same place as yours The green one (as in EVTM page 105) has a Y wire a R/Y, a BK but also a tan and a dark blue or purple with a stripe in it. It looks very stock and untouched, and should be fuel pump cutoff relay The grey has R, O/LB, PK/BK AND BR/W and should be tank selector relay, relay looks stock, but further down the add on has been spliced to the red. Sounds pretty good right? Christian - Yes, that's good. And you've figured out which relay is which correctly. Given that, it should be fairly easy to remove that extra relay and go back to stock - if that is what you want to do. Link to comment Share on other sites More sharing options...
Papelione Posted August 27, 2020 Author Share Posted August 27, 2020 Christian - Yes, that's good. And you've figured out which relay is which correctly. Given that, it should be fairly easy to remove that extra relay and go back to stock - if that is what you want to do. Ok From a safety view, would the add on fuel pump be cut off if the inertia switch or/and oil pressure switch opens? Im thinking the tank selector relay would loose power as intended and therefore the add on pump would´nt be getting power either? Sorry if Im stating the obvious .... But safety first. Link to comment Share on other sites More sharing options...
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