Has anyone come across a diagram of this.. Because the guy who owned the truck before me cut out the transfer valve and clipped the wires going to it and the fuel level senders too... So now, as far as I can tell I have 1 wire with positive potential(hot) and about 4 others That are not hot And does anyone know if this is the valve I need to get , http://www.classicindustries.com/truck/parts/17127.html
Hello 78 stepside,I have a diagram but no way of copying it onto the net so i will try help you with some of the wires, pink/black is the power supply to the switch on the dash pink goes to the dash gauge,lt.blue goes to the aux. tank sending unit,tan/wht or pink goes to the main tank sending unit,lt.green goes to the fuel switch that you are looking to buy that is the right one,Hope this helps if you need more info just ask or get the colors of the wires you have on there.Lots of times the dash switch gives problems maybe just order one at the same time or test it first,the lt/green wire should have power on one way and not the other.
Thanks a lot. I whent ahead and ordered the one from classic industries .. I guess that one is back ordered.. So I checked lmctrucks.com. They have one but it has three outlets on it unlike the one from classic that has many more.. The loc. Kragen auto parts store has this: http://www.oreillyauto.com/site/c/detail/BOR0/FSV1.oap?pt=N2000&ppt=C0025And lmc: http://www.lmctruck.com/icatalog/cc/full.aspx?Page=136They look to be the same. Any thoughts
Another question. The one wire that I found chilling one the passengers side chassis is tan and is hot in run and in accessory. It's justvlong enough to reach the fuel area. It was my understanding that the wires for the valve/senders came from the drivers side down and along the chassis. I don't believe that it's in the original and proper location
Ok well I pulled the switch no power to it..?with the switch diconnected. The wire that was going to the sending unit still has power. I'm thinking that the other owner bypassed the switch. With the test light as a load or in place of the sending unit it the gauge reads 1/2. Empty. Any Ideas where he may have bypassed the switch at? With the harness removed from the switch you can see the pink/black wire going towards the dash.Turns out that the black and/Pink wire plugs into the fuse panel and then from the fuse panel as solid pink to the instrument cluster. Another question would be, why do I have two tan(might be pink) wires along with the lt.green (solenoid) left ... I'm guessing that one goes to the fuel sending unit as mentioned by autotec. But what's the deal with the one left over?. I tested both of The tan wires to see if they were hot and no voltage was felt...I would think if they were for the sending unit they would have some positive potential ...When I tested the switch ..after plugging the red/blk wire in ,the lt.green would gain and loose potential with a flick of the switch..(good) But with the switch in both the open and closed positions no voltage was felt on any other terminals.. WTF ?
Sorry for the delay i am building a shop for my son and we got to drinking last night.The two tan wires go one to each tank.The switch just swiches them back and forth so if you ground the wires to the frame the gauge should read full on both sides,and if you have on-off on the green it should switch tanks on the tank switch.The fuel selector valve you want is the one with the 6 lines because you want to keep you return line from the pump and if you don't switch it it will fill one tank,this line keeps the fuel cool and from vapor locking at the pump.If your switch is not changing sides on the gauge from the pink to alternating tan the switch is faulty.hope this helps.The newer trucks have a diff fuel valve and switch the gauge at the soliniod so you need the one from that year and the switches are not interchangeable but 78-79 is the cheaper one and less problems.The part number 32-4036 from LMC is the one you need.
thank you again autotec. i was reading another post on a different forum. a gentleman was talking about this same circuit in and 1980. he said that there was a wire that goes to the sending units that runs along the backside of the engine along the chassis to the tank area. and that if the truck was setup with a single tank it the wire would go to the sending unit on the passenger side. but if the truck was built for a duel take setup, the wire would loup around to the driver side rail and back to the switch. this would make sense only to ease manufacturing w/options...
Ok well the the valve was discontinued from classic ind. So it's either I order the 5pin valve or I order the single wire 3 valve configuration... Any suggestions ... Wouldn't I have to wire the entire circuit just to accommodate the 5pin valve.?
Found this on
The switch on the dash is differant the wiring is differant it switches the gauge on the valve not on the dash so you would have to change everything to the new system.Can't get one at your local napa or outher parts store,maybe try partstrain.com someone should still have the one you need that would be easiest?
i broke down and called the dealer... they were reluctant to give me the part number... something about being liable if i ordered one from the internet and it was the wrong part.. but anyway ... he broke down and gave it to me.. PN#467513, its made by acdelco... they are selling them on amazon and a place called www.oehq.com i went with oehq.com because any order over $75.00 has free shipping. so i guess the plan now is just sit and await its delivery. autotec thanks again for your input, you have been a major help brother. i guess now all i have to do is figure out which sending units i need for both my tanks
well it came in the a day ago.. cant wait to get started lol. Happy Holidays everyone,Semper Fi.http://picasaweb.google.com/lh/photo/2qiR611eMTidPwhQ2ceKDw?feat=directlinkhttp://picasaweb.google.com/lh/photo/TF6eFNQuWRafoWrA09PNvw?feat=directlinkhttp://picasaweb.google.com/lh/photo/2qiR611eMTidPwhQ2ceKDw?feat=directlink
Now that you have the right one it should be easy to get hooked up now!
Some pics of my wiring progress http://picasaweb.google.com/lovegunn/1978ChevyStepside?feat=directlinkOf the switch and solenoid let me know what y'all think
Oh nice one , quite interesting, thanks for uploading pics, it would help many beginners like me to get out of trouble. keep updating