‘83 K5 Wiring diagram V8 vs V6 Firewall Block blue wire for oil psi switch requirement??? See pics

‘83 K5/crate 350/4wd: I am redoing some damaged wiring. The electrical schematic I have shows a blue (dashed) wire from the firewall block to an oil psi switch (6 cyl w/o gauges). I’m not entirely sure if this wire was connected to anything before I pulled the factory 305 to install my new crate 350. Please confirm if I need this wire for anything. I already have factory wiring for a factory style sender/switch for factory gauge and for an aftermarket set up. See 2 pics. Thank you!

BlazerBill said:

‘83 K5/crate 350/4wd: I am redoing some damaged wiring. The electrical schematic I have shows a blue (dashed) wire from the firewall block to an oil psi switch (6 cyl w/o gauges). I’m not entirely sure if this wire was connected to anything before I pulled the factory 305 to install my new crate 350. Please confirm if I need this wire for anything. I already have factory wiring for a factory style sender/switch for factory gauge and for an aftermarket set up. See 2 pics. Thank you!

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Need to see the whole dighram not just that piece. To me it looks like you are picturing the oil pressure switch that controls power to the electric choke,which if you have an electric chock on your crate engine you should put in the correct switch and hook up the wires to control the choke. Lots of trucks had a sender for a gauge and a 2 or 3 prong switch for the choke. If it is a switch for a light it will be a 1 wire. Lots will say just run a wire from the fusebox to the choke,meh, kinda passable,but not right especially if you have the ability to do it right.

I also posted another question/scenario that may comply with your response. This post is specific to the blue (schematic dashed) 931 wire that goes to a “Oil Psi switch (6 cyl w/o gauges)” as shown in the pic of the schematic. I may have already satisfied this requirement as explained in my other post and if so, what do I do with the blue (schematic dashed) 931 wire, if anything, since it’s specific to a V6 that from the schematic only had an oil psi switch and jumper wire to the choke and to the idiot light but strangely doesn’t show a sender (V6 specific).

BlazerBill said:

I also posted another question/scenario that may comply with your response. This post is specific to the blue (schematic dashed) 931 wire that goes to a “Oil Psi switch (6 cyl w/o gauges)” as shown in the pic of the schematic. I may have already satisfied this requirement as explained in my other post and if so, what do I do with the blue (schematic dashed) 931 wire, if anything, since it’s specific to a V6 that from the schematic only had an oil psi switch and jumper wire to the choke and to the idiot light but strangely doesn’t show a sender (V6 specific).

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Maybe not that year,on V8s but they used that same system on some year v8 trucks. Wire your V8 crate motor like it was the I6 if you are running an electric choke. The switch will be an off/on switch, off with no oil pressure,on with oil pressure. Is your switch connector a a 3 prong female connector,with wires going to the opposed cavities and nothing going to the odd cavity? I just saw your other post,you shouldn't have to make any splices,and @EvilGenius explained that circuit well,so I hope all your confusion is cleared up. You have a sender for tge gauge and a switch for the choke. I think I stated this on my first post?IDK anyway hope you understand it now.

Okay, along with my other post, I think I understand what you and @EvilGenius are saying. I must have misinterpreted the colored ClassicCarWiring.com diagram that says “Oil PSI SW (6 cyl w/o gauges-see pic) as meaning it was only specific to 6 cylinders (thus this separate post asking what to do with the 931 DK Blue wire). With y’all’s explanation, I now understand that my loose 931 DK Blue wire goes to the switch and is not spliced to the Tan wire that shows in the black and white Haynes manual that indicates that the DK Blue (931) wire is connected to the Tan wire (see pic) which is very misleading. So, all I need to do at this point is to UN-splice my DK Blue 931 wire from the Tan wire (to sender) and connect the DK Blue wire end from the switch to the other loose wire that I thought was specific to 6 cylinder engines. Make total sense now. Thank y’all, so much!