[for3300]

Hey Guys! New to the forum...but I have been reading alot of the post over the course of my project. I have a truck that has 83 Silverado body and 75 C20 engine . When I took the motor out I believe I broke the oil pressure switch wire. Now that the motor is back in I have no clue where the wire went to. I know it was a spaded connector. Does anyone know exactly where it goes, Fuseblock or connects to another wire??? I know it has power when you to the Start position and while the truck in running. The Fuseblock lettering is not legible for the most part thanks guys.

[C-10]

Tan wire position #31 in the harness connector for the '83 truck.

Your '75 engine just had just a switch (for idiot light) and not a 'sender' like the '83 engine. You can use the sender from the '83 engine for your newly swapped '75 engine. Rear of intake manifold behind distributor threaded into block.

[for3300]

Hey C-10 I really appreciate the quick response man! The only thing I don't follow you on is, "position #31 in the harness connector". I think it may be a terminology thing, I haven't heard that(I am far from a mechanic). I have some schematics and the Haynes repair book, also googled it, but I don't know what you mean by "position #31". I assume "harness connector" is the fuseblock on the firewall inside the truck, by the gas pedal, under the dash. Is there an easier way for you to explain "position #31" to me without taking a whole lot of your time?

[C-10]

Yeah harness connector at the firewall. Tan wire.

Your '75 engine could have had an actual 1/8th inch oil pressure line going to a gauge (mechanical) in the dash also. Either way, the '83 sender will thread into the '75 engine.

[for3300]

Ok I see on this schemetic for a 75 a tan wire going from the Oil Pressure switch to the Instrument Panel Printed Circuit Connetor, so I can take/splice that tan wire going to the back of the instrument cluster panel and wire it to the switch right?

[for3300]

sorry posted the above post before I saw you responded, thanks for the quick response

[C-10]

Pretty much. Use a volt/ohm meter if you are not absolutely sure you have the right wire.

Sounds like you have a good reference to go by.

[75gmck25]

If the donor truck had gauges (very common), the oil pressure gauge was mechanical, with a 1/8" metal line connected to the engine. They probably just snipped it off when they pulled the engine.

I've never really looked at one with an electrical gauge, but the sender would be in the same place as the '83.

Bruce

[fast68]

yeah in 75 it was mechanical oil guage

just swap the sender from the 83 engine to the 75 engine

always just behind the distributor

although some times there is another one sticking out of the the driver side of the block by the bellhousing down low.

but you can ignore that one, and it was mostly in the cars anyways

[for3300]

Many thx guys!, I was initially only trying to figure out how to wire the oil pressure switch, which I found out with your help, but I appreciate the extra info, so I can come closer to figuring out just how rigged up this truck was when I got it . Thx again