740 fuel gauge not working

[Choc]

I understand this is a common complaint, the fuel gauge on my 1988 740GLE estate is usually dead, very occasionally it staggers into life never going more than half full then goes back to empty.

I’ve read the excellent write-up here and I’ve been shopping in our Development Lab for a 68 ohm resistor. The question is, where do I stick it? When I lift the left access flap on the floor of the wagon, I can see 2 sets of wires. One goes into a plastic box then out again into the car, another goes into a multiplug. Which wires do I unplug, and where do I plug the resistor?

My Haynes manual doesn’t seem to mention the fuel sender at all in the wiring diagram!

[Choc]

I am such a tart.

After a fourth attempt at looking through the list in the Haynes book, I found the wire. I disconnected it, tried the resistor and just as suspected the sender isn't working.

Is it under the rear seat cushion? That could be next weekend's job