Automotive instrument


New Member
I am looking for a schematic for a circuit with a digital display that will show (selectively) oil pressure, voltage, and amperage. I would select which of the three would be displayed with a rotary switch. Could someone please either give me such a schematic or point me to one?

Thanks very much,


Senior Member
What sensors?
If you are using this on a post 1996 vehicle, then you would be best to get a "OBDII" scan tool and pull this info into a PC. See

If you want to use "dumb" instruments, which will be supplemental to the post 1996 vehicle sensors (so you aren't messing with the factory electronics) then you can probably find something close at jcwhitney.


New Member
I should have stated that the car is a 1999 Saturn SC2,which is OBDII. There is no oil pressure gauge nor meters for voltage or amperage. I did look at Whitney and a few others but no one has anything even close to what I would like.

The use of a scan tool and a laptop did occur to me as there is software available for a laptop and scan tools with USB connectors but for my purposes that is severe overkill.

A while ago someone on the Saturnfans site mentioned that he created a home-built device like I described but he seems to have disappeared without sharing his knowledge.

So I search...