Oil light / oil pressure switch odd behaviour

Post by **MattBW** » 16 Apr 2014, 16:52

So I've had my engine bay rewired as it was rather messy. After reading a lot of threads I am still at a loss.

In the process of doing this we have found that the oil light was missing and a new seperate light had been wired in. We assume this was added because the PCB is rather poor. Before the rewire the "new" light would come on and go off once started. Since the rewire the light stays on permanently.

Replaced the oil pressure switches but it still seems to be working backwards. Have we missed something in the circuit? The circuit is sound and works and has been tested, it just seems to be working in reverse to how it should.

Engine is running fine and feel no different. We are due to get a oil pressure test done this week but we suspect its electrical.
Any advice anyone can offer? As said the circuit and earth seems fine.

Post by **dave friday** » 16 Apr 2014, 18:05

What switch did you replace it with?

Post by **MattBW** » 16 Apr 2014, 18:11

I replaced both switches, ordered based upon the engine code and reg plate. The ratings were identical struggling to remember, main one I think was 1.2-1.6 and the other would have to check.

I have wondered if the oil pressure control unit is duff, but I don't know where that is or what it looks like.

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Post by **dave friday** » 16 Apr 2014, 18:21

Have got one of those cheap digital test meters?...first though pull the wire off the sender on the front of the head then turn on the start key to the first position,is the warning light on or off now?

Post by **MattBW** » 16 Apr 2014, 19:05

It's off until it's started then it seems to come on even with wire removed from head but left wire on filter housing

Post by **dave friday** » 16 Apr 2014, 19:27

The wire on switch on the oil filter housing should be yellow ...the wire on the other should be blue/black,have they been swapped?

Post by **MattBW** » 16 Apr 2014, 19:51

They had to be rewired in due to a faulty wire, it is possible. I will have another look tomorrow and try swapping them. Many thanks, would be quite funny if thats all it was

haha.

Matt.

Post by **MattBW** » 18 Apr 2014, 19:59

Bit of testing today and it looks as if the electrician maybe connected them the wrong way round due to the old wires being wrongly coloured. The second wire is too short to test properly so I need to extend that wire to know for sure. Still need to do a bit more testing but it may have been as simple as that. Lol.

Thanks for your advice.

Website · Post by **CovKid** » 19 Apr 2014, 23:37

True story Matt and not for the squeamish but years ago a friend of mine had a green 1303 bug called 'Fat Bob' with a rebuilt engine that had the oil light on permanently. Initially it was a concern but it ran perfectly fine and we drove hundreds of miles in it. We just plonked a lump of blu-tak over the light in the end - problem went away then.

Post by **MattBW** » 20 Apr 2014, 10:14

LOL not sure I am that brave

After an afternoon testing yesterday a

further development, the water temp connection was unto the other oil pressure switch, so the dash was showing full temp and overheating once started.

So now I need to work out where the water temp sensor is to connect that too and work out which of the other connections is the actual oil pressure connector for the one on the oil filter housing.

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