Larry, it looks like you are taking a picture of the wiring under the plywood deck. The main pump is connected under the rear seat. The sender access plate has two cables; the gray one with the blue and black wires goes to the speedometer pickup on the differential -- nothing whatever to do with fuel. Now I am guessing you tested the polarity reversal of the main pump by swapping polarity on the speedometer transmitter!

The gray wire (not white) is the sender wire. It runs the fuel gauge. The brown wire is the ground. The black wire coming from that plate and the sender unit is the hot wire for the tank pump.

Do you have a Bentley, Haynes, or Volvo wiring diagram?
Do you have a way to make your pics something like 640x480. I'm way past having sharp vision.


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Art Benstein near Baltimore

When the smog lifts in Los Angeles, U. C. L. A.