Brake and oil light

ghost · 03-09-2009, 04:06 PM

Hello:

I am a newbie to this forum. I have a 1983 Porsche 911 convert. that drives great. The brake light (emergency brake light), comes on after a few minutes of driving, and i have noticed lately that the oil warning light also comes on...sometimes around the same time.

The oil level seems to be fine.

I did some research on here, and i found out that the brake light is due to a faulty switch in many cases. Then I read a post that mentioned that since the oil light comes on around the same time.....then it might be oil sending unit?

I will try to disconnect the battery, to see if that will resolve the issues.

If not, what do you guys think the likely cause (switch, oil sending unit, other..?)anyway to know for sure?

Thanks

dshepp806 · dshepp806's Garage

Brake light indicates that the pads are up for changing...(assuming the circuit is functioning properly.......May indicate a low fluid,...I can only speak from MY 89.

Oil pressure light,..another discussion. Could be the sender (change it out)....or it could be be the real deal...(measure oil pressure)...or, possibly, metering (gauge).

AGAIN, these commented items are for my expreience with '89 (not '83),..much less a "convert".\\

Sounds like it could be 2 separate issues and should be investigated.

Then, again, it could be common,..although I wouldn't know how so without seeing the electricals. When were your pads last changed?

How's the oil pressure gauge reacting, per RPM? Good pressures? Maybe the sending unit, in addition.

You've a few paths to investigate, for sure.

Best,

Doyle

VaSteve · 03-09-2009, 07:07 PM

Quote:

Originally Posted by dshepp806

Brake light indicates that the pads are up for changing...(assuming the circuit is functioning properly.......May indicate a low fluid,...I can only speak from MY 89.

An 83 is different.

Welcome, Orginal Poster...post photos.

The oil pressure "dummy" light is wired up so that the brake light will come on at the same time. If the pressure (next to the tach) is OK ~1bar per 1K RPM, then the sender (in the back of the engine, near the flywheel) is bad. If the pressure is bad, stop driving.

ghost · 03-16-2009, 03:53 PM

The oil pressure is not exactly 1 rpm to 1 bar all the time....sometimes it is, other times its about 2 to 1 or so, depending on acceleration or gear selection.

However, i think that after 5-10 minutes of driving and not with 100% certainty but when the oil pressure goes under 3 or 2 bar , both the emergency brake light and the oil idiot light both seem to come on at the same time.....

So is that a symptom of oil pressure warning light that causing both of these lights to come on, or something else? How do i verify for certain if it is a (switch or sender, or something else).

VaSteve · 03-16-2009, 05:08 PM

Quote:

Originally Posted by ghost

So is that a symptom of oil pressure warning light that causing both of these lights to come on, or something else?

That's most likely what it is. That's how it went on my car. It's a $10 part, but a little challenging to swap without at least a partial drop. I'm not sure it can be tested. They call it the idiot light for those that choose not to look at the oil pressure gauge.