07-11-2018, 08:46 PM
Join Date: Mar 2009
Location: Georgetown, Guyana
Unless I'm very much mistaken, an 86 Samurai will not have an oil pressure gauge as a standard fitting - there will be a speedometer, fuel gauge, water temp gauge, and possibly a tachometer - as on most cars, low oil pressure is indicated by a warning light as are under/over charge conditions.
I want to suggest that you find an auto electrician, your mechanic is obviously out of his depth on this - power does not come from the fuel pump or the oil pressure switch, in fact, on an 86, the fuel pump is mechanical and driven off of the camshaft - no electrical connections at all.
The gauges - fuel & temp - and all of the warning lights get their power from the ignition switch, and they ground via the sensors or senders - the low oil pressure warning light is a very simple circuit - one wire takes power from the ignition switch to the bulb, and a second one connects the bulb to the switch on the engine block - it shouldn't take an experienced auto electrician more than a few minutes to troubleshoot that, and probably less than an hour to a separate warning light if you choose to go that route.
Diagrams & manuals are available from Ack's FAQ.
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