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Ignition key on…no oil pressure light

1K views 18 replies 8 participants last post by  turboguzzi 
#1 ·
1993 Suzuki Vitara JLX, Greek market, 1.6 liter, 8 Valve, soft top, manual…

Just bought the cheapest 4x4 on the entirety of Greece. Runs good. Cel is off on ignition. Will check bulb. But I want to fix oil pressure light first. With ignition on, the oil pressure light will not go on. With engine running and the oil pressure wire disconnected and grounded on the block, the light will come on. With engine off, there is continuity on the switch top and ground on engine….with engine running there is no continuity. So the oil pressure switch seems fine. Also bulb is fine…but bulb does not come on with ignition on. Any suggestions welcome.
 
#2 ·
Welcome to the forum. Hopefully others with more electrical knowledge than I will chime in. Have you actually, physically checked the oil pressure?? The oil pressure, with the engine running, needs to be at least 4.5psi at idle. I suppose it would be a good idea to remove the switch and connect a mechanical gauge, start the engine, and confirm that you have the proper oil pressure…..
 
#9 ·
I would have to buy an oil pressure gauge tool. Might be a good addition to the ever expanding tool box ;). Not sure how often I would use it tho. Maybe for the same price I can buy an aftermarket oil pressure gauge and mount it near the dash. Get real time pressure readings…and not just the switch. Either way…I’ll look into this…thanks…🙏
 
#3 ·
If the light does not come on with the engine off and the ignition on, but, it comes on when the wire is grounded to the block, the switch IS defective. There is a very slim chance that the wire is broken and when you're moving it to ground it to the block it temporarily heals the break, but I doubt that is the case.
 
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#4 ·
Yeah, but what is weird here is that the switch reacts as it should (circuit test wise) with the advent of pressure and then without. :unsure:

With engine off, there is continuity on the switch top and ground on engine….with engine running there is no continuity. So the oil pressure switch seems fine.
 
#5 ·
Bad connection at the contact terminal on the switch would be my guess.
I have had this before, touch it with a multimeter probe and its fine, put the wire back on, doesn't work. Ground wire, light comes on. Just the slightest bit of movement in the terminal pin into the switch was the cause of the problem
 
#11 ·
But I tested the switch…and it is working…perhaps there is more to it than simply circuit testing it…
Like I said before, I have had them test ok but still be faulty when you connect the wire back on.
Will the switch actually carry load? You can have continuity without the ability to carry current.
Did you test it with an incandescent lead light or a multimeter ?
 
#15 ·
The FSM basically says that when the oil pressure switch doesn’t light with key on, you disconnect the switch and connect a fused jumper from the switch connector to a chassis ground. If the warning lamp lights then, replace the switch. If it still doesn’t light, then the FSM directs you to the instrument panel cluster connector, to test resistance there, potentially looking for an open in the yellow/black wire.
 
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