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73-87 Chevy _ GMC Trucks => Electrical => Topic started by: Rip on May 07, 2013, 01:47:27 am
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I have a '80 Silverado Stepside Big 10 with a 350 4 bbl and TH350. It has duel tanks with mechanical pump. The tank valve is the type with one light green wire to it from the switch. Also coming from the switch is a red, pink with white stripe, blue, land dark green wire. The dark green wire goes to a connector that attaches to the side of the fuse block. It has other wires that go different place but nothing is plugged into this connector. My first question is what plugs into this connector? I think the red wire actually comes from the fuse block and runs down the passenger frame rail around back up the driver side rail the the switch. Is that correct? The blue wire goes to the driver side tank and the pink with white goes to the passenger side tank. Those are for sending units? At the switch, with it flipped down to the left tank position, with a test light i have power on the red wire with the key on run. The blue wire is hot at this time also. The gauge shows past full. When i swtch the selector to the right tank, the gauge shows empty(which it is), and the red wire goes dead as well as the blue. Question 2 is shouldnt the red wire stay hot and the blue and pink with white alternate with the switch being flipped? Question 3 is shouldnt the light green going the valve get hot at some point to activate the valve? I changed the switch but it made no difference. Any help would be appreiciated.
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The grounds coming from the tanks were checked and they seem good, im wondering now which on feeds the gauge? I checked old posts and most deal with 5 wires on the valve or for 85 or 87 trucks. There are there are suction and return lines going from the valve to the pump and the same lines going to each tank.
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these might help: http://forum.73-87chevytrucks.com/smforum/index.php/topic,11766.0.html
oh and Welcome to the Forums!
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It helped some but not totally. Im gonna try to look in the tech pages again. Thanks though!
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I have a '80 Silverado Stepside Big 10 with a 350 4 bbl and TH350. It has duel tanks with mechanical pump. The tank valve is the type with one light green wire to it from the switch. Also coming from the switch is a red, pink with white stripe, blue, land dark green wire. The dark green wire goes to a connector that attaches to the side of the fuse block. It has other wires that go different place but nothing is plugged into this connector. My first question is what plugs into this connector? I think the red wire actually comes from the fuse block and runs down the passenger frame rail around back up the driver side rail the the switch. Is that correct? The blue wire goes to the driver side tank and the pink with white goes to the passenger side tank. Those are for sending units? At the switch, with it flipped down to the left tank position, with a test light i have power on the red wire with the key on run. The blue wire is hot at this time also. The gauge shows past full. When i switch the selector to the right tank, the gauge shows empty(which it is), and the red wire goes dead as well as the blue. Question 2 is shouldnt the red wire stay hot and the blue and pink with white alternate with the switch being flipped? Question 3 is shouldnt the light green going the valve get hot at some point to activate the valve? I changed the switch but it made no difference. Any help would be appreciated.
For the subsequent discussion, locate the "Auxiliary Fuel Tank" wiring on page 11 of this wiring diagram (http://www.73-87chevytrucks.com/techinfo/7387CKMans//Wiring/ST_352_80_1980_Chevrolet_Light_Truck_Wiring_CK_10_30_Only.pdf).
You should see five wires connecting to the tank selector switch: (1) pink/black (ignition source from fuse box), (2) light green (to tank selector valve), (3) pink (becoming tan as it passes thru the 4-wire firewall connector, loops down the left frame rail then back up the right frame rail and into the cab to the fuel gauge), (4) light blue (to left tank sender), and (5) pink/white (becoming tan/white between the 4-wire firewall connector and right tank sender).
It sounds as though the selector switch isn't connected to Ignition at the fuse box - perhaps a blown fuse, or the wire is unplugged. Ignition connects to the dash switch solely to energize the tank selector valve - it has no electrical connection with or bearing on fuel gauge function. The 'dark green' wire you observed at the fuse box may actually substitute for the 'pink/black' wire in the wiring diagram. Study the diagram carefully and compare it to your switch wiring to puzzle it out.
The power you're registering with your test light on the light blue wire is actually coming through the fuel gauge. The gauge is powered directly by ignition. The tank sending units are variable ground connections that modulate the gauge.
Once you've pondered this information for a bit, if you have more questions post them. And, let us know how it turns out.
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It seems it goes back to my first question. What might plug into the connector that the green wire goes to? There is a pink with black stripe wire from the fuse block, an orange wire from the fuse block, the dark green wire going to the tank switch and a black wire that im not sure where it goes. The pink, orange, and green form a u shape and the black is off to the side. Next to the black is an unused terminal. The pink with black stripe and orange are from different terminals on the fuse block but are both hot in run. It seems there is a relay or something that should bridge the pink or orange to the dark green. Anyone have any ideas? The wire diagram only downloaded to page 7 after trying a couple of times. I tried to post a picture of the connector im talking about but its to many kb.
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The connector terminals are female so whatever plugs into it would have 4 blades, 3 in a u shape and 1 by itself.
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Hopefully someone recognizes it.
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I tried to post a picture of the connector im talking about but its to many kb.
Go here for a "How to" to resize pics (http://forum.73-87chevytrucks.com/smforum/index.php/topic,6428.msg33935.html#msg33935). You can also use MS Office Picture Manager packaged with some computers, etc.
Is this the connector you have plugged onto the selector switch (Delphi P/N-8911352 (http://www.pcsconnectors.com/8911352.aspx) - pictured below)?
The wire diagram only downloaded to page 7 after trying a couple of times.
I've attached the auxiliary fuel tank wiring diagram in PDF format, below.
It seems it goes back to my first question. What might plug into the connector that the green wire goes to? There is a pink with black stripe wire from the fuse block, an orange wire from the fuse block, the dark green wire going to the tank switch and a black wire that im not sure where it goes. The pink, orange, and green form a u shape and the black is off to the side. Next to the black is an unused terminal. The pink with black stripe and orange are from different terminals on the fuse block but are both hot in run. It seems there is a relay or something that should bridge the pink or orange to the dark green.
In general, GM factory wire colors are: Pink/Black = ignition; Orange = fused battery; Red = unfused battery; Black = ground. Your setup isn't using the standard color combination for the fuel tank selector, so images will be very helpful if you can post them.
In the meantime, if the connector on your selector switch appears as pictured (five terminals), then two wires attach to one side of the selector switch, and three wires attach to the adjacent side of the switch. The 'two-wire side' controls ignition power to the selector valve. The 'three-wire side' controls which tank sender is connected to the dash gauge. If the connector isn't as pictured, then the second tank may have been added later and its wiring may not exactly follow the factory schematic(?). So, post pics.
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Hopefully someone recognizes it.
Is that the connector off the switch, or off the fuse block, or...?
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Thats the female connector that clips to the fuse block. The duel tanks are factory and the switch connection is the 5 wire with 2 on one side and 3 on the other.
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This is it clipped on the fuse block above the direction flasher.
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This is the back of it and you can see the space it clips to on the right side above the flasher.
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The pink wire with the black stripe from the plastic connector at the top left corner goes to the connector, as well as the orange that is between the speaker wire and the yellow wire at the bottom right.
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The dash switch has 5 wires coming off it, the dark green goes to the unknown connector, the pink with white stripe, light green, blue, and pink go through the firewall like its supposed to, the only thing is instead of a pink with black stripe wire going from the fuse block to the dash switch, it goes to the connector and a dark green wire goes the dash switch. The connector seems factory in the way it attaches to the side of the fuse block.
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That is not how my truck looks. I just redid the entire dual tank setup.
My switch has 4 wires coming off the dash switch.
Pink/White for hot that goes to IGN on the fuse block.
Pink/Black for ground that goes to the buss bar on the parking brake.
DK Green for Right tank
LT Green for Left Tank
the DK Green and LT Green go through the firewall by themselves. They come out between the brake booster and the cruise servo.
I do not have a BLUE wire at all. Here is the schematic I used to redo my dual setup.
(http://i6.photobucket.com/albums/y228/Sabaka454/control.gif)
That connector almost looks like the high beam switch that is in the floor. That connector DOES have a BLUE wire so I don't know who fudged that whole setup.
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The dash switch has 5 wires coming off it, the dark green goes to the unknown connector, the pink with white stripe, light green, blue, and pink go through the firewall like its supposed to, the only thing is instead of a pink with black stripe wire going from the fuse block to the dash switch, it goes to the connector and a dark green wire goes the dash switch. The connector seems factory in the way it attaches to the side of the fuse block.
It seems that ignition power for the selector valve should arrive to the dash switch via the 'dark green' wire coming from the 'mystery connector' on the fuse block. Post a pic of the backside of the connector plugged onto the dash switch that clearly shows which wires enter which cavities. I want to verify switch wiring before making a recommendation. My guess at the moment is similar to yours... there's a module/relay missing from the 'mystery connector,' but I'm missing the logic for two power sources to it....
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Perusing service literature to find additional info, if possible....
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Boone83K10: From that wiring diagram, you have the motorized tank selector valve, where the two leads to the selector valve reverse + and - to switch tanks. I think the solenoid tank selector valve, with a single lead to the selector valve and a frame ground, is what he probably has.
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Hope this is clear. The side with 3 wires is from the top, blue, pink, and pink with white. The side with 2 wires is from the top, light green, and dark green. This is the connector at the back of the dash switch. This view is through the hole in the dash with the plug turned around to show the back. I cant figure what would need two hot leads either. I think i heard something about a timer that would keep a system pressurized after the power was shut off to help avoid vapor lock, but cant remember what years or models it was used on, or where i heard that. I think i could bypass the unknown connector to put power to the dark green to feed the valve through the light green, but i dont really want to alter it. Its a california truck if that would help.
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The dark green wire connects to ignition through the 'mystery relay/module.' I'm unable to find any reference to the missing component. I'll keep my eyes open and post here if something turns up. To make it work (temporarily) and check the function of the selector valve, jumper fused ignition to the dark green.
What color wires plug into the two terminals at the top of the 'mystery connector and have you figured out where they connect?' The timer module to which you refer is used on later TBI vehicles with electric fuel pumps.
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The wire colors don't match, but the right circuit diagram for what you have is probably the one toward the bottom of this page: http://67-72chevytrucks.com/vboard/showthread.php?t=558564
In that case, dark green is definitely the hot from the ignition socket on the fusebox, light green goes to the solenoid valve, the two outer wires on the other side (light pink, light blue) are the sender unit wires from the tanks, and the center (darker pink or red) wire is to the gauge.
Voltmeter checking should show: dark green wire hot all the time, light green wire either hot or open depending on the switch, light blue and hot pink wire should be to ground through a resistor with a value between 0 and 90 ohms depending on fuel level, and the center dark pink/red wire should read hot from the gauge. Grounding the hot pink/red wire should send the gauge to EMPTY.
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bd- into the mystery connector is the dark green wire that goes to the switch, pink with white from the fuse block, orange from the fuse block, and a black ground that junctions with other black grounds in a connector behind the dash.
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this should help some...
(https://fbcdn-sphotos-e-a.akamaihd.net/hphotos-ak-ash4/417965_10100682880129838_1822108682_n.jpg)
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I had the valve bypassed and just the left tank hooked up, but now i put a jumper wire in the connector from the pink with black wire to the dark green wire and i have power to the valve. I havent put gas in the right tank yet but i think it will work fine now. The gauge still goes past full on the left tank so i will have to check the wire to the tank for a break.Whatever plugs into the connector seems like it could do different things depending on how the wires are on the connector, since there is an unused terminal on the connector, like another ground for the orange wire from the fuse block, although i dont know why they would include the orange but not the other black. I looked on the options list anf other than duel tanks and carb it doesnt list anything about the fuel system.
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I'm supposing that ignition and ground provided the control to energize the relay/module, which then connected battery (org) to the dash switch (grn). It will be very interesting if we're ever able to determine what they were trying to accomplish and why the extra complexity.
On the left tank showing past full, don't neglect the ground connection to frame from the sender. You can check the sender by unplugging it from the circuit then connecting an ohmmeter between the sender signal wire and ground wire. It should register somewhere in the range of 0 - 90 ohms.
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I had the valve bypassed and just the left tank hooked up, but now i put a jumper wire in the connector from the pink with black wire to the dark green wire and i have power to the valve. I havent put gas in the right tank yet but i think it will work fine now. The gauge still goes past full on the left tank so i will have to check the wire to the tank for a break.Whatever plugs into the connector seems like it could do different things depending on how the wires are on the connector, since there is an unused terminal on the connector, like another ground for the orange wire from the fuse block, although i dont know why they would include the orange but not the other black. I looked on the options list anf other than duel tanks and carb it doesnt list anything about the fuel system.
I think you need to forget about that connector. I think someone just used whatever they had laying around. I don't even know why they thought that "plug" would transfer power through because it has female ports. I don't get why there is a DK GRN wire because nothing on the schematic about that. Why not just wire it up like the schematic I gave you.