My oil light has not worked on my 91 dx in the 6 years of ownership. I have tried swapping out clusters, the sensor, the harness and bulbs.. My last endeavor, I spliced the line directly to back on the cluster for the light. I have searched and someone said to make sure it's grounded, but it's only one wire. It has not worked on the d15b7, d15b vtec, mini-me and zc vtec. All of which had their own sensors, and I recently, last year, switched out to a si cluster which all the bulbs were working on that.

I was running a p08 ecu, which I read does not read a oil pressure sensor for vtec. I am now on a p28 chipped from phearable.net.
Only thing I can think of is that the current has to be closed for the light to come out, if it ever gets below 4.3 psi. I can check for continuity with the engine off, but where would I check, since everything has to be tied off? It's not like I can just check for voltage from the plug wires like everything else.

 

with the engine not running, unplug the yellow/red wire from the oil pressure switch, and check for continuity between the post on the switch that the wire connects to and ground - there should be continuity (switch closed) - with engine running there should be no continuity (switch open)

 

Thanks I will try that

 

ok, no continuity from switch. I swapped out wire and plug with a spare, still no light. But, then again, it is wired into the line now to the oil light on the cluster. I am going to break that connection and run it back to the ecu, but the wire it was connected to at the ecu was not working before working either.
I am seeing the A4 pin on the ecu, but that showing up as the vtec oil pressure switch on some sites. Any verification?