Low Pressure Warning Light Fed From Gauge Feed


Ok so one here for the electronic whizz kids out there, so I have a oil pressure gauge, the sender does have an output for a warning light but its a real ball ache to get a cable back to the dash so I was thinking is there a way to trigger a light from the gauge feed, its a resistance based circuit, ETB tell me the gauge runs 10 Ohms static (0)
184 Ohms full scale so I was thinking of a system where a light was triggered say 20 Ohms, if its a linear scale then its about 3 Ohms per psi
A light would always eye catch more than a dropped gauge so its something I wished I had done at the time of wiring....
Done a web dig but nothing


While looking for a suitable comparator I found this:

It is a complete printed circuit board with parts mounted. It is powered by 12V and the trip point is adjustable from zero to +10V. There is a small LED indicator as well as a 10A relay on board so you can switch almost anything. The price is $12.99. You can't build one this cheap.

Randy V

Lifetime Supporter
I may not be understanding the issue fully....
Why not just install a “T” in the oil pressure feed line, then screw in a light sender from a 65-66 Ford Mustang? I believe they tigger at 10 PSI pressure...

Bill Kearley

You could add a T at the oil pressure port, but like you said another wire to run and a hole to drill for the light, a pain.
I think I'd T into the oil port and use it for an auto ignition shut down with an over ride for startup, a hidden button on the firewall like mine.

Ian Anderson

Lifetime Supporter
could you ask ETB if they can do a pressure gauge with a warning light fitted that works with a single wire?

i know when I asked them to do my gauges they said they could make adjustments if required.

The only thing they could not do was a fuel gauge with two needles one for left and one for right tamks



Hi al, thanks for the info and tips, I had seen a comparator Neil but could not find a suitable circuit, I agree a wire best but a pain to fit my sender actually has a feed for a light but its a long way from the dash!! ETB Ian I will ask. Nice idea re left and right tank bit like an aircraft manifold pressure gauge!!!
I'll ask ETB and look at that comparator as well, thanks all