Oil light permanently on, with a twist....

Ok got a problem which I'm getting a bit narked off with now….!!!

Car background: Originally 1.6gti, which started smoking big style, so dropped in a mk2 1.8 8v engine, that had already been in a mk1.

Recently had an electrical problem where the wipers and fan blower would stop working,. After poring over the wiring diagrams in Haynes and taking half the dash out, traced it back to the 'X' relief relay that was being tempermental. replaced relay, wipers and fan work…. Great.

Start engine and the Oil warning light in now permanently on. Because the dash was still out I've checked the connections between the fusebox and the switch, between the points on both sides of the fusebox, and from fusebox to dash light - all ok.

I've since replaced the switch on the oil filter housing, as well as the filter, the oil pump was changed about a month ago and should still be good….

Now I'm stuck. The other switch in the side of the head is not connected to anything. Not because I'm lazy, but because there was no switch in the head on the 1.6 engine, so I've no wiring to connect to it. I know this because the old engine is still in the garden with the snails.

So, any ideas?? There's no buzzer sounding, it doesn't matter whether I rev it above 2k or not, and oil does seem to be getting round the engine ok….

Help!!!

Cheers,

Andy

Interesting problem me i would remove the bulb fit an oil pressure guage [VDO] using the correct sender that goes where the presure switch was and be happy with that ?

Cheers……………….

I have heard of this before,I have just changed engines in my car my original engine only had the one switch and the new engine has two.Check the colour of the switches as one makes earth and one breaks earth.Normaly they are black or white.If you have a white switch fitted swap it for a black one or visa versa and see how that pans out,That was the problem I had with mine.I hope it is that simple for you,best of luck.
                        Baller

Cheers for the replies. I've now got the right switch in position but the light's still on. Really starting to hack me off!!

This exact same this has started happening to my brothers Mk1 after i replaced the clocks yesterday. Dont know if it helps but this is what the Bentley MK2 golf manual says and so far as i can see the same oil switches are used:

With ignition off, low pressure switch is closed (complete circuit to ground).
When ignition is turned on, indicator flashes (no pressure).
When oil pressure rises switch opens, breaks circuit to ground and inidcator goes out.

To check switch:
1. Simulate a closed switch by grounding the blue/black stripe wire attached to switch. With ignition on it should flash. If it doesnt problem is in circuit or indicator. If indicator only flashes when doing this replace switch.

2. If indicator flashes when engine running and oil pressure ok, remove blue/black wire and indicator should go out. If it doesnt the circuit is shorted to ground between wire and indicator. If it does go out the switch is stuck closed and should be replaced.

The situation with yours (and my brother's too) is different as its not flashing but you may be able to rule out some components. ie. pull off the blue/black wire with ignition on. If it goes out brilliant as it rules out dodgy earth elsewhere in circuit. Now, assuming light went out with last test, touch wire to cylinder head and it should light up again. If it does, but doesnt flash then presumably something in the dash clocks is upsetting it.?

I would check earth continuity through the switches when they're supposed to be on and off according to the stuff at the top. I'd also check the voltage getting to the dash oil light (terminal 9) via the multiplug with ignition off, at first position and car started and see if anything leaps out at you. At least, thats what i was planning to do if the car were not on holiday in wales atm.

Id be interested to hear your results so post them up.

Just for comparisons sake: On my brothers car (1983 1.3 driver) the oil indicator doesnt light up at first position on ignition (when it should do, like the battery light does) but comes on instantly when you start the car and stays on permanently.

I confirmed this by checking the multiplug connector (without clocks attached) with ignition at first position so dash would normally light up and got ~12v between the dash power supply (terminal 14) and battery warning light/fuel guage/temp guage terminals (suggesting they'd power up) but nothing btw power supply and oil indicator (terminal 9) when presumably you should do if the wire is earthing via the oil switch, which should be closed if engine isnt on?

This was without the dash even connected so rather upsets my conclusion in the last post that its something in the dash clocks causing it. This is why i was planning to check continuity to earth of the oil switch during start up.

You know anyone with a Mk1 nearby who would be willing to swop clocks around? Might help rule out dodgy dash.