PatrickGSR94

iTrader: (1)

Way back in the day, like Christmas 2004, I had a problem with my 94 GSR's battery charging light staying on with the car turned off, and the oil pressure light on with the car on, despite everything running normally. It turned out the problem was the alternator, which I figured out by looking at the wiring diagrams, and finding that the alternator was the only thing in common between the battery charging circuit and the oil pressure light circuit.

In the past week I've had a couple of instances where my oil pressure light started flashing, but everything seems fine. Engine runs and drives fine, oil level good, and so on. I'm going to run the tests on the pressure switch and the ICU outputs this weekend to check for issues there. Also a couple of weeks ago, I replaced the ICU with a unit I bought off eBay along with the full interior fuse panel about 2 years ago, and just never got around to putting it in until now (I only changed the ICU). Maybe that's the problem also, so I might throw the old ICU back in (replacement didn't change anything anyway) and see what's happening there.

But I was just wondering if anyone has had their alternator cause such issues with the oil pressure light flashing. The car's original alternator was replaced in 2004, but I replaced it with one I bought from a friend that came out of a 99-00 B16 Civic Si. That alternator has been in the car ever since late 2004 so nearly 12 years now.

fcm

The alt. should have no effect on the oil warning light , it is not connected to the light at all other then, [in a roundabout way] the ground. 94

PatrickGSR94

iTrader: (1)

Yes, it is actually. It's connected to the voltage regulator in the alternator through the ICM for the oil flasher circuit. FSM page 23-144, white/blue wire. That's how I figured out the alternator was likely responsible for the oil light and charging light issues back in 2004.

fcm

That connection should be a yellow/red to the ICU, and if they were connected why is the alt. light not flashing also???? 94

PatrickGSR94

iTrader: (1)

Well in the case of 12 years ago, oil pressure light on when car running, battery light on when car off. Replacement alternator fixed both.

So I guess if the battery light isn't doing anything, then the issue isn't the alternator?

fcm

Either not the alt. or a problem with alt. light. 94

NVturbo

If a new alternator fixed the problem, the 12VDC power for the oil pressure switch is somehow tied/linked to the alternator. Car manufacturers have a tendency of connecting different sensors on the same circuit. If this wasn't the case, the fuse box would be as big as residential/commercial electrical panel. LOL