hi everyone, so i recently bought a volvo 240 and some of the gauges are not working. the oil pressure gauge being the most pressing. the sender unit which im assuming is the thing just to the right of the oil filter has two terminals and only one wire attached that disappears into a coil that goes underneath the alternator. the only loose wire in site is a green insulated wire encased in black plastic below the sender unit. not sure if this is the wire im missing there or something else. so i guess what i ned to know is whether that is indeed the sender unit and where the second wire might be hiding out. thanks a lot!

oh also how do i get the sending unit out if i need to replace it? cant find anything in the manual.

The electrical terminals on the sending unit should be labeled "G" and "WK." "G" is for gauge and "WK" is for the **** light.

The sending unit unscrews from the block. Lefty loosey.

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I guess the swear-word filter didn't like the word "I-D-I-O-T," as in i**** light.

The 1991 240 did not come with an oil gauge as standard. They were only fitted as standard in the 240 turbos. So chances are a previous owner installed the gauge. So check the wiring at both ends of the gauge for the correct colors etc.
Nice 86 is correct about the terminals: "G" on the sender is for gauge and it should have a green wire the "WK" should have a black wire. Make sure that the green wire is also connected to the "G" on the gauge. The gauge should have a blue/red wire that goes to the fuse box (usually fuse 11) for power, 2 black wires for ground and a grey or brown wire for the gauge light,
If the wires to the sender are switched, this can fry the sender (been there done that...).
Also it's likely that you have a Metric/NPTF adapter to fit the VDO sender into the B230F block.
You'll need to take the belts off the alternator to loosen the sender.
If the sender is bad, a good source of used senders are VW cabriolets and Audi 4000s.