In a message dated 4/13/98 1:46:30 PM Eastern Daylight Time, KMNTR6@aol.com
writes:
> What does the oil pressure have to do with the Brake
> warning light?
Ken and Bruce,
The oil pressure switch is wired such that low oil pressure will light both
the oil warning lamp and the brake warning lamp. Both lamps are wired in
series with the oil pressure switch, so they both glow at half brilliance when
the oil pressure is low. When the brake warning switch is actuated, only the
brake warning light is lit, and it is lit at full brilliance, as it not in
series with the other lamp at this time (the brake warning switch bypasses the
oil light).
As silly as this sounds, there is a good reason for it. Hopefully, you will
never see the brake warning switch operate, but the low oil pressure switch
operates every time you turn the key on until the engine is up to speed. By
wiring the lights in series, the driver has the opportunity to check both
bulbs for operability every time he turns on the key. You should be in the
habit of looking to see if both lights come on - otherwise, the bulbs could
fail and you would never know it. If the bulbs should fail and you get a real
brake warning or low oil pressure, you would not get the indication and a lot
of damage could be done.
Regardless of the bad things we say about Lucas, the designers of the
electrical circuits in these cars really knew what they were doing. Just for
information, the testing of the brake warning light in an MGB is done by
pressing the warning indicator lamp on the dash. How many MGB owners know
this? Not many, because the question comes up quite often on the MG list. In
a TR6, the testing is done automatically for us, so we don't have to remember
to do it ourselves. We just have to remember to look at the lights when we
turn on the key!
I'm not sure what that says about the relative intelligence of MG owners
versus Triumph owners (in my case, it is the same, since I own both -- come to
think of it, I don't know what that says about me!)!
Dan Masters,
Alcoa, TN
'71 TR6---------3000mile/year driver, fully restored
'71 TR6---------undergoing full restoration and Ford 5.0 V8 insertion - see:
http://www.sky.net/~boballen/mg/Masters/
'74 MGBGT---3000mile/year driver, original condition - slated for a V8 soon
'68 MGBGT---organ donor for the '74
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