Oil pressure switch question for 69 v.w.

[Buick35]

I'm just about ready to fire up my v.w. motor.It's on an engine stand and my question is how to connect an idiot light to the switch/sender.I have a small working light bulb with the ground wire attached to the side of the base.I know the sender is normally closed and oil pressure opens it. Do I connect the red wire to the coil and the ground to the sender connector? It lights if I ground the wire but doesn't if I connect it to the sender. Could the sender be bad or did I wire it wrong?Thanks.

[Rusty_OToole]

The sender grounds the light. If you connect the bulb to the coil+ and the other side to the sender the bulb should light when you turn on the key or connect the coil, and go off when the engine starts.

Edited June 2, 2023 by Rusty_OToole (see edit history)

[Rusty_OToole]

[Frank DuVal]

Rusty's right. 

 

Hot wire to one bulb contact, other bulb contact to switch terminal. Do NOT ground one of the bulb terminals like in a regular taillamp circuit.

[Buick35]

Thanks,the bulb I was using only has one contact inside the bulb holder and a ground wire from the outside of the holder.It came with an aftermarket gauge.So I need a bulb with two contacts?

[Bloo]

As long as you have 2 wires (hot and ground) and neither of those are grounded to the car, you're good. The bulb itself doesn't matter so much. Run the hot wire to 6V(or 12V), and the ground wire goes to the oil pressure switch.

 

As long as the socket is not getting a ground some other way, it will work.

 

Edited June 3, 2023 by Bloo (see edit history)

[Buick35]

Thanks,I'll try that.If that doesn't work I'll get a new switch.