Oil Pressure Switch - Simple Question...

[GLPoomobile 958]

Is it usual, or common, for the oil pressure switch to fail completely, or do they usually just get a bit random and unreliable?

 

I think mine is completely dead. I've never had a working warning light, and assumed it was a dead bulb. Then after I replaced my loom I tested the wiring while I was at it, and it still didn't work, and I sort of just forgot all about it. Now I've just tested it again and I get nothing at all, so I just want to check that this really is an obviously dead switch or if I'm missing something else.

 

Using a red LED (that is known to work, as I tested it right before) I connected one end to the oil pressure switch wire in the brown plug under the dash, and the other to a switched live, and the LED stayed unlit. I do remember checking by connecting directly to the switch ages ago, but I've a funny feeling I might have had a blonde moment and connected both ends to earth on that occasion, which proves nothing (you know how you sometimes get random flashback memories of things you did ages ago, and realise you made a mistake ).

 

So in a nutshell, does it sound like a duff switch?

[Tom Fenton 1,542]

God knows what you are up to with the LED and so on.

 

The easy test is, unplug the wire, earth the spade connector to the block. Meanwhile have glamourous* assistant observe the light on the dash, this should light up when you earth the wire. If so, you have proved everything else is as it should be, and the switch is most likely duff.

 

*this part is optional

[pablo 0]

as above its a very simple circuit.

[GLPoomobile 958]

God knows what you are up to with the LED and so on.

 

The easy test is, unplug the wire, earth the spade connector to the block. Meanwhile have glamourous* assistant observe the light on the dash, this should light up when you earth the wire. If so, you have proved everything else is as it should be, and the switch is most likely duff.

 

*this part is optional

 

I totally forgot this crucial bit of info - I'm pretty sure that earthing the terminal to the block was the first thing I tried. And that's why I thought the bulb must have been duff. So it's entirely possible that I have both a blown bulb AND a dead switch.

 

I used the LED because I had it to hand. It will eventually (when I get the switch working) be wired in as a secondary oil pressure warning light. I could have used my multimeter, but the LED was easier as I could stick the bare ends in to the plug terminals and leave it in place.

 

So in summary

1 - Pretty sure I've tried earthing the sensor wire to the block and got nowt (but will re-check in due course)

2 - Wiring should be OK as it's all new

3 - Tested using LED connected to +12v and the sensor wire where it joins under the dash and got nowt

4 - Think I did the same test with one end directly at the sensor, but so long ago I can't remember

 

Yes, it is a very simple circuit. Hence this should have been a simple question and a simple answer, just like I said at the start

[pug_ham 244 3 Cars]

Have you had the clocks out to check the bulbs are ok?

 

Graham.