mytrplseven

My oil pressure indication is full scale without engine running (ignition switch on). I've checked the wire connections at the pressure sender/switch and they can't be mixed up because the round connector only fits one of the wire lugs on the switch. With the wires disconnected from the switch I am getting the voltages as shown on the diagram attached. The switch itself checks out fine.

The Blue wire shows +12 VDC and the Blue/White wire shows around +5VDC. Looking at the diagram, the wires are going through a thick black "something" on the diagram that has no description. If anyone can enlighten me about the info I've provided and whether it's right or not, I'd appreciate your insights. I'm thinking that the Blue wire shouldn't be showing +12 volts but not sure, since I can't decipher a path to it's source.

thomasmryan

I would assume its the engine harness plug/connector.

ddombrowski

If the wires are connected to the oil pressure switch, what are the voltages you get at the back of the oil pressure gauge?

joes

What does the gauge do if you unplug the wires? if it goes to zero you have a bad sender. If it stays pegged tap on it could be stuck. If it is still pegged with the wire off (or key off) you have a bad gauge. One wire is for the oil light/ attention light the other is variable according to resistance to ground (oil pressure) If you ground the one wire the light should come on. Ground the other it should peg the gauge. Also if the gage pegs with the wires off and the key on it could be shorted to ground some where in the harness.

mytrplseven

The latter is the issue. Any idea which wire (blue or blue/white) goes to the gauge? I seem to keep pulling the gauge cluster and the intake manifold over and over. Now, the throw-out bearing started growling and the clutch chattered while pulling into the garage. AAAAggghhh!

Ok, now I see the blue/white goes to the gauge and the blue goes to the warning light. Tomorrow's another day of debugging.

marc abrams

On a 83 N/A blue/white is for the gauge. I don't think they changed it thru the years.

mytrplseven

I was just running the signal lines again and finally deduced exactly what you said. I appreciate the input.

mytrplseven

Finally got some time away from family stuff and started chasing this problem again. I found the pins on the sender were shorted between each other and also shorted to the sender case. So I guess I'm springing for a new sender. I'm going with VDO since I don't really have confidence in some of the other mfr's stuff where electrics are concerned.

mytrplseven

VDO oil pressure sender arrived today and cussed my way through the swap and now I have Low Oil Pressure warning light that wasn't there before and proper oil pressure indication. One more item to check off the list.