M30 oil pressure light odd goings on

[Rav335uk]

Yes, all enjoyment, but at a cost.

[jimbom30cab]

Ok I have fitted a nice new oil pressure sensor, no change

I am still getting 12v only to the sensor when cranking , when the engine runs there is no voltage

I have done the c101 pin 3 and 8 swap mod also

Whilst in the c101 plug I noticed that pin 15 and 18 have been bridged with some heavy duty wire and solder?

Not sure why this is but the car won't start without it

I've got a spare loom (un-mullered)and am tempted to just swap the looms

It's the loom I just got from Lee which is for an auto car.

[jimbom30cab]

So I have now 12v out from fuse 10 when engine is running,

From here the 12v goes to the instrument cluster where there is 12v going in, this lights the low oil pressure bulb ( if there is a circuit) from the bulb it goes back out the instrument cluster through the c101 to the pressure sensor plug.

If there is oil pressure the switch opens, sending the circuit to open circuit and then the warning light goes out.

So the problem I have is that there is no power from the dash to make the circuit, hence the warning light stays on.

I have tested there is no 12v out from the instrument cluster - I stripped some insulation off the output wire which is brown and black and there is 0v with engine running.

I also tested for continuity between this point and the OPS plug and there was some beeping so either they are connected properly or they are both earthed!

My guess now is that the instrument cluster is not duff as I have 2 known working ones both used, but that it is unwanted earthing somewhere?

Nothing else on that circuit works either, no Eco swingy, no horn and no reverse lights, also no coolant temp gauge

So the option to fit a oil pressure dial rather than a switch is a non-starter.

I'm kinda running our of options now. .

More research and thinking time

I used to say on the submarine that electrical problems took 95% time to diagnose and 5% to fix

I'll revise that to 99%

LOL

[mcbonio]

I'm sure you'll figure it out Jim. Just keep at it. You could ask Brian Moore, he's an electrician and knows e30 wiring like the back of his hand. He really helped me out when I had that faulty alternator that tested good but ran bad.

[jimbom30cab]

Thanks mate, I put a post in the tech help section, so hope Brian sees it

The only thing I can think of next is to change the engine loom as maybe something is just not right. My loom is a second hand one and has plenty of 'adjustments'

[mcbonio]

Does kinda sound like an earth problem.

[jimbom30cab]

I think it could be a serious option also Chris,

My engine loom fitted has many many non-oem 'adjustments' so I'm going to fit a factory fresh m30 loom and start again

Not this weekend though, time for some family time (BBQ and beer)