Engine Warning Light Inputs? '93 SNOB

Correct. When a fault is detected by either switch (low oil or high temp) the switch connects to ground and the light turns on. It also grounds the input to the protec module and causes it to go to limp mode.

When you rewire for the DUI make sure to keep that circuit and your light will still work.

You can test the light by turning on the key and either disconnecting one of the wires at the switch and touching it to ground or using a jumper wire from ground to one of the switch terminals.

KENO wrote: I think I'd be lazy

No you wouldn't. You would check them both just like I would.

And then Ken would disassemble his own dash wiring and show the proper hook-up technique. This would include photos (with Ken’s hand holding something) and a winky emoji. But you would have solid info on how to fix the problem.

There would also be a link to another thread showing a similar problem and fix.

JQ

Nauti Gator wrote: Thanks guys - I ran new wires to the existing water and oil switches then tied them into the 12v feed that the Protec system previously used - so when I check voltage there is 12v present going to both switches - when I ground the switch the dash light comes on. Is that correct? Is there supposed to be 12v present at each water and oil switch when the key is turned to the ignition Position?

In the ignition(Start) position you should have battery voltage which will be lower since the starter is drawing a lot of current right at that time, but there should be voltage present, just like there's voltage present in the Run position.

And when you ground either switch in Start or Run the dash light should come on