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bguy's avatar
bguy
Explorer
Jun 19, 2019

FW sensor wiring help

Hi all.

I had my FW tank out to repair the floor. Being around the block a couple times I made a sketch of the wiring on the cardboard I was using as a creeper.

About a month later when I used the tank for the first time I discovered the tank moniter only reads full or 1/3. Hmmm. Maybe I wired it upside down. So this evening I took down the underbelly again and reversed the wires. After all is said and done it seems like only the top and bottom wires were reversed. It seems to be working now but just thought I'd pick your brains before I put the underbelly back.

I have a large gauge White wire pig tailed to a small gauge white wire with a screw loop. I think this may be the feed wire. Next I have a large gauge Blue wire pig tailed to a lighter gauge wire, green I think with a screw loop, which also has connected to it an ID'd lighter gauge wire( could be blue and yellow ) that's pig tailed to 2 more light gauge wire with screw loops, blue and yellow.
At first I had the white wire at the top, then the blue wire, yellow wire and the double wire at the bottom. I reversed all 4 wires, but now have just the top and bottom reversed and it seems to work. So now it has the white wire at the bottom, yellow, blue and the double at the top.

Opinions please. It's the strangest wiring I've seen.

4 Replies

  • DrewE you are spot on. I now realize that the connectors look sorta like fuse holders but are obviously resistors. Thank-You!
  • Typically those sensors are wired to a resistor string. The pigtail connections probably contain the resistors. Often it's all in one blob of epoxy or plastic or something with a bunch of wires coming out, but yours seem to be strung together.

    If you disconnect everything and measure with an ohmmeter, you probably could suss out the connections. On the other hand, if the lights are all working as expected (they go on as you fill the tank at the appropriate levels), then I would say it's correct enough and leave good enough alone.
  • Apologies for lack of clarity. This is my Fresh Water tank.
  • wa8yxm's avatar
    wa8yxm
    Explorer III
    The tank monitors do not work, never have, save for a freshly steam cleaned tank, and never will unless you steam clean teh tank.. Poor design. You do however have choices

    1: Seriously clean. There is one cleaning wand (I made my own before I saw it) the Valterra Master Blaster.. I do not like the design of it but mine is different. a 1/2 inch pvc pipe capped with a hole about 1/4inch. in the SIDE of the cap/pipe (not the end) blast that ... stuff off the wall so teh sensor can dry out.

    2: Horst Miracle probes.. I plan to test them... Some day.. But have yet to get the reound-tuit needed Company claims they work I've heard good things from alleged customers but I have not tried.

    2: See-level that works. Totaly different type of sensor.

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