oil light issues

[Spidermann]

This is a strange one
The oil light comes on when I switch off my engine?
oil in car,oil pressure good, car runs sweetly, but when I switch the engine off on comes the oil light dimley.
Any sugestions please would be greatfully recieved !!!

[Penelope Stopit]

Does the dim light extinguish if you disconnect the oil pressure switch?

If not

Does the dim light extinguish if you disconnect the alternator warning light wire

[Spidermann]

Thanks o rsuch a quick response, fantastic
No change when the sensor wire is removed.
where is the Alternator warning light wire please? or take off the gang plug to disconnect?

[Penelope Stopit]

Are you able to disconnect the alternator warning light wire at the back of the alternator?

If you do disconnect the alternator warning light wire and the dim oil light goes out there is a very good chance that the oil and alternator warning lights are wired the wrong way round

Something else you can do is, disconnect the oil pressure switch and see if the alternator warning light has stopped lighting up with the ignition on and if it comes back on when you re-connect it

Edited by Penelope Stopit on Monday 9th July 18:53

[Penelope Stopit]

If you get as far as thee above and have proven that the wiring is the wrong way round, now with the ignition off you should have a dim alternator warning light when you have corrected the wiring

A dim alternator warning light with the ignition off is often caused by a faulty diode trio in the alternators rectifier pack

[Spidermann]

disconnecting the oil sensor light has no effect on the Alternater circuit at all.
I could get the wire off the aternator a long screwdrver but it would impossible to get it back on as I have air con and there is just no room for long pliers let alone hands!!
I am thinking it would be safe to say the wiring is the right way round given the Alternator works fine.
I was thinking bad earths?
or 100amp Fuse?

I will try again tomorrow if you have any sugestions I am open to anything as this makes not sense to me at all TBH.

[Penelope Stopit]

Ok, it does seem like the circuits are the correct way round

I need to know if the oil light comes on at full brightness when you switch the ignition on and what it then does when you disconnect the oil pressure switch while the ignition remains on/is left on

[Spidermann]

tried again thismorning.
no effect with sensor wire connected or disconnected
Oil light only ever comes on when I turn the ignition off
Noticed there is an electrical component not sounding right.
There is what sounds like an acuator or electric motor quickly going on and off.
It is located on the passenger side to the left of the glove compartment up just under the dash.
I have no idea what it is as all other systems are working will try and get a photo to try and identify it.
Perhaps that is causing a dead short through the oil warning light curcuit?
getting stranger and stranger.

[Penelope Stopit]

That noise you mention is very likely a ventilation flap stepper motor running when it shouldn't be and also unlikely to be related to the oil warning light fault although anything is possible, someone with more Griffith experience than I will be along shortly to help you with this stepper problem

Back to the oil light. Ok, In your opening post you didn't mention that the oil light doesn't work with ignition on

You need to be very careful when checking for this fault, I will post more on this later

If the oil pressure switch is of the switched earth type and sends that earth to the instrument cluster warning light and doesn't connect to the engine ECU (I do think this will be the case, oil switch direct to oil light), one side of the oil warning light will have an ignition positive to it and the other side will connect to earth through the switch (the same as the alternator warning light works but that earths through the alternators rotor)

For the oil light to stop working as normal yet glow when the ignition is off suggests that the cable from the cluster to the switch has a problem

There is a voltage but not 12 volts on the oil pressure switch cable and when you switch the ignition off that voltage is going to earth through the ignition side of the bulb, the ignition positive supply at the bulb becomes enough of a negative polarity so as to act as an earth for the bulb when switched off

In summary to the above - Ignition cables show as positive with the ignition on but will act as negatives when off, enough of a negative to earth a small warning light bulb

If I was you I would be looking for a rubbing engine loom by working back from the oil pressure switch, you need to be looking for the oil pressure switch cable rubbed through and partially shorting to a battery positive
Also bear in mind that a corroded multiplug will also show this very same fault, the oil switch cable pins in a plug could have corroded away and are shorting through corrosion

A short on the wiring harness is favourite

I post the above assuming that the instrument cluster wiring has not been messed with and is in good order

You need to be very careful when checking for this fault

If there is a short anywhere on the wiring harness you could easily disturb it while checking it through and cables could short out more and burn, obviously this depends on the type of short/fault

Disconnect the battery and connect it back up with a 30 Amp in-line blade type fuse, now you can safely have the ignition on while moving cables to check for a short on the loom knowing that if anything shorts out badly the fuse will blow

Good luck in tracing the fault

There is a chance that a short on the loom could be to blame for the stepper motor or whatever to make a noise, there is also the possibility that if you don't find a short on the engine loom or in an engine bay plug that the problem is inside the vehicle.....Engine looms are always favourite and best carefully checked before delving deeper

Edited by Penelope Stopit on Tuesday 10th July 13:01

[Spidermann]

Ordered the inline fuse.
Just noticed there is a very slight glow on the yellow low fuel warning light now which goes out when I put the alarm key in the docking port before I start the car
This only comes on when the Alarm system activates the imobiliser cuircuit?
If I turn on the ignition without putting the Alarm key in it's dock the yellow light glows fully and the steppermotor I mentioned earlier starts and both will only stop when I put the alarm key in it's dock.
The heater controls have not worked for years, I assume due to heater control unit fault but never use the heaters so not bothered fixing it.
This all seems to be getting a whole lot worse as we speak!!

[Penelope Stopit]

There could be a bad earth somewhere and they do cause strange faults
You need to work through the oil light fault or another and finding the fault may well solve several others
Easier said than done I know but you have to start somewhere or pay a good Auto Electrician and they are hard to find

[Spidermann]

Thank you "Penny" you have been a star!!
I will work through the oil light issue first and also on the way check and re-make the earths as I go just to make sure.

Thanks again for all your help

Kind Regards
Wayne

[Penelope Stopit]

Glad to be of help
Post back here if you get stuck on something, there are others that can and will help