Oil press/temp alarm - 1988 4.3 not working

When I got my boat the alarm didn't work. Its an 88 SeaRay 210MC with the 4.3/Alpha 1. I was told that leaving the key in the "on" position, but not starting it will test the alarm. But I get nothing.

Can anyone tell me what/where the alarm circuit is?

There is an orange/purple wire with a corroded end dangling in the bilge, I cannot locate where its connected as it goes into the main harness, it appears to be a 14/16 guage wire with a 90 degree connector (Looks like is slipped on a post somewhere).

I'm chasing some gremlins, looks like the PO installed new gauges in the last couple years, but did a **** poor job of wiring. The temp gauge is intermittent and the oil press seems to be reading high, which I'll have to confirm with a mechanical gauge.

Re: Oil press/temp alarm - 1988 4.3 not working

I have a 1988 Sea Ray as well, but a 20' bow rider. Wiring should be the same, however, and the alarm circuit is a Tan wire with blue trace. Mine runs from the buzzer to the coolant sensor (on thermostat housing), to an oil pressure sensor (near oil filter). I believe all the coolant/oil pressure sensors do is ground out to complete the circuit.