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Gas tanks

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 85Silverado, May 3, 2002.

  1. 85Silverado

    85Silverado Registered Member

    Mar 28, 2001
    Likes Received:
    Knob Noster (yes), Missouri
    85 Silverado. Dual tanks. The LH one seems to read ok on the gage. When I go to RH I get a short sound of the valve working (not as long as when I hit the LH one) but the gage doesn't move. I drove it for about 40 miles and it didnt move off of FULL. I wish it were true but it's not. It's a gas hog. Any ideas of where to start?

  2. TX Mudder

    TX Mudder 1/2 ton status

    Jul 10, 2000
    Likes Received:
    Each tank has a pink wire that goes all the way up to inside your cab that connects to your rocker switch for your tanks that is just to the left of the ashtray.
    Since one side is working, I would not suspect the switch itself. I think it is the pink wire that goes from the suspect tank to switch. You'll have to check it.
    ALternatively, it could be the actual sending unit on the tank. If that's bad, you're out of luck. Removing the tank to install a new sending unit is a PITA.
    You'll be checking the sending unit also when you're checking the wire. The fuel guage is a resistance tyhpe guage. One end of a floating bob is in the tank and moves up and down depending on gas level. The other side of the floating bob connects to a rheostat and varies the resistance depending on how up or down the bob is.
    So set the multimeter up on ohm's (aX) and check it out. Sorry I do not know the range of resistance, but you can easily check the other tanks and since it is, say, half full you will know that is how much it should read for half full.
    -- Mike

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