Oil warning light related to handbrake switch?

[Andy Esprit SE]

Has anyone ever come across this odd fault before? (I have a video I'll try get on you tube and add the link)

If I start the car with the hand brake on, the low level oil light comes on when you rev it up, if you start the car with the hand brake off its perfectly fine.

I've had my car 18 months or so and it's always been like this, previous owner thought it was the handbrake switch at fault but as he couldn't find a new on just carried on starting it with the hand brake off.

Could it be an earthing fault? Thus when power goes to the hand brake light three a faulty reading to the oil level sensor? I was thinking about getting a second hand switch from Douglas valley as it's only diwn the road from me?

[Andy Esprit SE]

[Neil Potter]

I'd have thought it must be earthing but seems very odd they would be linked.  Parts list says there's an earthing braid going to the scuttle beam on the RHS; which I presume you can access under the dash but I've never seen it on my carb turbo, not that I've been looking for it, that would seem to be the likeliest candidate.

 

Engine sounds great btw; must get myself a new exhaust!

[CHANGES]

Hi Andy,

The Warning light check relay is the only common denominator i can see...

[CarBuff]

If you have a poor earth, the current seeks an alternate earth from any path. If that path takes it through a light bulb, the current flow will illuminate the bulb.

 

That said, I can't hazard a guess why yours works the way it does.

 

 

++++++++++++

 

I have a similar weird issue since I had my engine out:  The BRAKE lamp in your video stays on at idle, even with the brake lever down, but goes out over 1500 RPM. During this time, the voltmeter stays at 12.5V engine off, 13.9V engine on (new Bosch alternator).  ????

[CHANGES]

The only way the brake w/light can illuminate when h/brake off is

1 faulty switch.... easy check..

2 fluid level switch ....easy check

3 low vac switch ...  easy check

4 w/light check relay..... uhmmmm

 The question is why it flashes on the oil pressure light...

The only common denominator is they both go though the check relay.

[Andy Esprit SE]

Thanks for the replies fellas, I'll be shopping for a relay shortly and go from there.

I'll let you know how I get on

[Mike6]

Not sure this is relevant but isnt the handbrake warning light linked to the seatbelt warning light ie they share the same bulb. Could it be that someone has messed around with the warning bulbs to get it through the MOT. I have done this myself!!!

[Vanya]

I'd guess it's the check relay - I sometimes have odd issues like the Brake Warning lamp staying on after the rest of the lamps have gone out. Turning the ignition on and off usually gets rid of this. I believe it could be the channel in the check relay acting up in your case also?

 

..more importantly perhaps, where do we get a hold of a new relay?!

Edited February 10, 2014 by Vanya

[Andy Esprit SE]

I borrowed a friends service notes but there for the S3 thinking it might give me a clue where the relay is, I didn't realise the service notes were so informative I'm gonna get on the hunt for a set now I have the numbers for the 88-92 ones.

Can anyone advise where to find the relay? There's an S4 being broken at Douglas valley I can hopefully go and see if it has the same one?

Edited February 10, 2014 by Andy Esprit SE

[mdw]

They call it a tell tale module I think ( it may be labled as such and from memory its yellow) .  It looks like the 2nd relay forwards in the stack under the bonnet. NON abs car its on the rh side  and ABS is on the left ( both 2nd row going forward).

 

As  your a FF member  down load the pdf of the parts manual for 88-92 cars  and its labled  on page 17.03a

Edited February 10, 2014 by mdw

[Andy Esprit SE]

Found it, thankyou