Wiring a Low Oil Pressure Warning Light

[MrDomino]

I have an OP Sender rated for 20psi and a warning light. On the OP sender there is a single post for an electrical connection and there are two posts on the light. One of the ones on the light goes to ground. How do I connect the OP sender to the lamp. Somehow the lamp needs to get power but also has to get an input from the sender. I'm not sure how to wire everything up.

 

I've searched on the interwebs but have only really gotten a bunch of info about people trying to figure out why their oil pressure light is on in their car.

 

Please help.

[Legends21]

Mr. Domino:

 

Let me tell you up front, I am guessing how your low oil pressure switch is working. If you could take an ohm meter and see if the switch is normally open or normally closed at low pressure, we would know for sure.

 

I am guessing the low pressure switch is normally closed at low oil pressure. And I am also guessing the switch shorts the terminal to the base and therefore to ground. If that is the case, you will need to wire your light to +12 volts and disconnect the ground wire. The wire that you had grounded at the light, should be connected to the low oil pressure switch terminal.

 

Good luck.

 

Dale

[MrDomino]

Mr. Domino:

 

Let me tell you up front, I am guessing how your low oil pressure switch is working. If you could take an ohm meter and see if the switch is normally open or normally closed at low pressure, we would know for sure.

 

I am guessing the low pressure switch is normally closed at low oil pressure. And I am also guessing the switch shorts the terminal to the base and therefore to ground. If that is the case, you will need to wire your light to +12 volts and disconnect the ground wire. The wire that you had grounded at the light, should be connected to the low oil pressure switch terminal.

 

Good luck.

 

Dale

 

So something like this? (The OP sender is just a regular warning light sender- I can't remember what brand but it's exactly like one you'd get from Longacre)

 

 

That would make sense considering the OP sender for the pressure gauge also grounds at the threads.

 

I'm a Mech Eng so the electrical stuff is foreign to me. So the sender grounds the one terminal from the light? If 12 volts is already making it to the light wouldn't it illuminate regardless of the OP sender? I honestly have no clue.

 

 

 

 

Another separate question

 

For the gauges, do I have to wire each +'ve directly to the source and each -'ve directly to the ground or can I connect them all and then have one wire go to ground?

 

[mbuskuhl]

Wire the OP sender like your picture. From the light one wire to 12v ign and the other wire to the male spade connector on the OP sender. Don't run a wire from your battery for the 12v either, find a wire that only gets 12v when the ignition is on. Real easy to confirm it works as when you turn the ignition on, the light comes on. Start the car and seconds later the light should go off as the OP rises above 20PSI.

 

As far as your other gauges... looks like you are trying to wire up the backlights? If this is a race car, throw them away, unless you are doing night time enduros. Yes you can splice them all together like your picture, again pull your 12v from an ignition wire.

[MrDomino]

Wire the OP sender like your picture. From the light one wire to 12v ign and the other wire to the male spade connector on the OP sender. Don't run a wire from your battery for the 12v either, find a wire that only gets 12v when the ignition is on. Real easy to confirm it works as when you turn the ignition on, the light comes on. Start the car and seconds later the light should go off as the OP rises above 20PSI.

 

As far as your other gauges... looks like you are trying to wire up the backlights? If this is a race car, throw them away, unless you are doing night time enduros. Yes you can splice them all together like your picture, again pull your 12v from an ignition wire.

 

Alright, thanks.

 

I figure I'll wire up the backlights to the light switch on the car. That way they're only on when the headlights are on. If I'm ever driving the car at night or like you said a night time enduro then I'd like to be able to see what is going on.

 

Again thanks for the help.

[Legends21]

.... Don't run a wire from your battery for the 12v either, find a wire that only gets 12v when the ignition is on....

Yes, I should have specified an ignition switched 12 volt source!

 

Dale