New guy, old truck, oil pressure issues

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animal

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86 SCOTTSDALE

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Welcome From Mass. The one on the right could be a safety switch in case oil pressure drops too low. My 86 K10 has the one on the left and a second sensor with a two wire connector next to it feeding off the same fitting.
 

Thomas89

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Just to follow up for posterity, the image isn't exactly what I was looking for. Turns out the one on the right isn't the one that's in use in my truck. It should have two terminals with the black plastic harness connected. (I've included the correct image this time.)

Dave M. I believe you're correct. The two wire version sends signal to the electronic choke heater and the gauge. Maybe someone who understands wiring diagrams can better explain.

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Dave M

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@Thomas89 This may be a little long winded, but l hope this helps. The two wire switch does not send signals to both the electronic choke heater and the gauge, as one unit.

If your truck is fitted with the factory oil gauge you need the large sender to operate the gauge. The Tan wire comes from the gauge to the sender unit. Increase in oil pressure will vary the resistance within the sender, to ground, to make the dash gauge read correct.

Should you also have an electric choke, the motor will also have a separate two connection oil pressure switch, which closes (makes the circuit), upon the engine achieving oil pressure, power from the p/white wire (IGNITION SOURCE), then goes through the switch to power the choke heater via the L/Blue.
There are also 3 wire oil pressure switches available, which control the electric choke as well as operate the oil pressure indicator light for non gauge dash panels.

The pic of the latest switch you posted is probably a later replacement, same function as the old one, but just a different plug receptacle. Anybody please chime in if they can offer more.
 

Ricko1966

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Did you remove your switch from the side of the block or from behind the distributor? Your oil pressure sender is behind the distributor. It is 1987 correct,? Should be TBI.
 

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