Re: 81 Glastron SX-190 Transom and Engine- PICS Galore Update 11-8
Friscoboater,
My wiring had the nav lights and anchor lite on opposite sides of the same dpdt switch, crosswired so that in the nav direction all came on. Ib the anchor position the all around light came on by itself. I'll be breaking mine out seperate like yours.
The gas gauge:
Without the mystery component, my gauge gets a positive, ground, lamp, and sense connection. If you tie a variable resistor of around 300 - 500 ohms between the ground and sense terminals, you should be able to sweep the full range of the gauge. I tested mine that way. The gauge actually works between 0 and 160 (or 90) ohms (have to look it up but it's not critical for testing) but anything over that will work. If the resistor is too big, you won't be able to see the sweep well since the range is all at one end. The Added box may be your problem also. If it ties into the equation, it could be not working right and dragging the meter down.
In summary the simple path is posotive wire - gauge positive terminal - gauge internal workings - gauge sense terminal - sending unit posotive - sending unit internal resistor - sending unit ground - gauge ground terminal. All this is simply a variable resistance between the sense terminal and gauge ground.
It is entirely possible that the extra ground wire at the sending terminal went to a common somewhere, or someone was lazy enough to tap a ground there for use elsewhere.
Sorry I tried to dumb it sown so much, but a schematic would be easier. Gotta run now, but I'll try to post a drawing this evening if you wish.