Why doesn't my oil pressure light work properly?
Asked by Jeff Dec 06, 2023 at 11:10 AM about the 2012 Chevrolet Equinox 1LT FWD
Question type: Maintenance & Repair
I have a 2012 Equinox. When I turn the ignition on, the oil light comes on for a
bulb check. If I don't start it the light goes out. I back probed the wire to the
ECM and the signal wire shows to be grounded. When I start it the wire goes
open. This tells me the switch is working as designed. What tells the light to
come on?
7 Answers
That's a normal function, the ECM and the BCM both control the warning lights. As the computer do not see a run signal from the engine they selectively turn off non-functioning circuits. My Equinox does the same thing if the engine is not started. If you have a complex enough scanner you can actually watch the computers activate or deactivate circuits.
Ohh and if you do want to do testing make sure you have the right test equipment. These Equinox's are very finicky about what you can get away with and might just blow something out of spite. LOL
beatupchevy answered 4 months ago
What threw me with idiot lights is that both terminals are + , They come on with just batt juice but when the car starts the alternator output exceeds the 12 V at the batt . Now the ECM runs the show I guess
Yep, with both computers communicating with each other and taking over even the basic warning light operations as well as full accessory control it make usual diagnostics a mute point. Gone are so the days of using a incandescent test light to see if a gauge will read or even testing a circuit.
