Speedhut oil pressure sender connections

[EZ$]

OK, so I've read a bunch of threads regarding how to hook up the sender, but I'm still confused (big surprise)!
I know Jeff Kleiner recommends using the harness wire supplied by Speedhut in place of the wire labeled for the oil pressure sender in the RF harness, which is where my confusion lies. I thought that it would be as simple as connecting the RF wire labeled for the oil pressure to the sender, and then run a wire to a ground from the other pole, or am I missing something? I really respect what Jeff has to say, but I don't understand why I would run a new wire when there's already one for that specific use.
Can somebody explain this as though I didn't understand the electrical wiring at all, which I obviously don't.

[Avalanche325]

The RF harness is set up for a 1 wire sensor. The Speedhut gauges use 2 wire sensors.

That was the most annoying thing to me on the entire build. The harness is set up more for Autometer gauges rather than the, pretty much standard, Speedhut gauges.

[Jeff Kleiner]

I posted this to your same question on the other forum. Avalanche already covered pretty much what I said in the last paragraph.

The Speedhut senders do not ground through their cases and therefore need both a signal and ground wire. Couple of options to carry the signal to the dash; (1) use the 2 wire Speedhut cable and run it all the way back to the dash then simply connect the wire that you have on the sender's "-" pole to your dash ground and the one that you have on the sender's "+" terminal to the gauge--- OR--- (2) instead of using the Speedhut cable connect a wire from the sender's "-" pole to a good engine ground and connect the RF harness "oil pressure sender" wire to the sender's "+" terminal with the other end connected to the gauge. Either works although I generally use option #1.

As for "but I don't understand why I would run a new wire when there is already one for that specific use" part of your question...remember, the RF harness isn't Speedhut specific so if for example you were using Autometer gauges which DO ground through the sender's case you would simply connect the oil pressure sender wire in the engine harness to the sender and the other end of it in the dash harness to the gauge. Speedhut's need for a separate ground changes things a bit.

HTH,
Jeff

[EZ$]

After answering on the other forum, I just thought of a quick follow up question. The water temp., and oil temp. senders are only set up for one wire. Since I believe that the gauges are grounded behind the dash, there isn't any need for any additional grounding, is there? OK, one more thing. The volt gauge, I thought that I read that it could just be connected to the brown gauge feed wire to operate correctly. Is that correct?

[Jeff Kleiner]

After answering on the other forum, I just thought of a quick follow up question. The water temp., and oil temp. senders are only set up for one wire. Since I believe that the gauges are grounded behind the dash, there isn't any need for any additional grounding, is there? OK, one more thing. The volt gauge, I thought that I read that it could just be connected to the brown gauge feed wire to operate correctly. Is that correct?

Yes and yes. Use Teflon paste on the senders and not tape which can compromise their ground.

Jeff

[FFinisher]

Sorry to burst everyone's bubble here,....but..... the latest Ron Francis harness uses both a signal and ground wire for their senders, and there is no reason not to use the Ron Francis harness. Although the leads from speed hut are shielded, SpeedHut will tell you its perfectly acceptable to use the Ron Francis harness. I do it all the time.


You will need to use the connectors for the senders from the Speedhut leads, I cut them off Solder them onto the Ron Francis Wires, heat shrink at the sender end -and connect them behind the dash to the dash harness

This cleans up the wiring in the engine compartment and simplifies the wiring behind the dash. Since the Ron Francis harness already has the gauge connectors on it for the Speedhut gauges it couldn't be easier behind the dash

[GFX2043mtu]

My 2017 kit had 2 wires unfortunatly the ground was chassis ground and caused the gauge to intermittently drop and then return every so often. I ended up using the speed hit wires.