At 08:23 PM 6/19/02 -0500, MonteMorris wrote:
>.... 67B, which had been blowing the bottom fuse as soon as I turned it
>on. .... take all three green wires off the fuse terminal and plug them in
>one at a time to see which one blows the fuse, and/or check
>continuity. Two of the wires caused the short and both had no continuity
>when tested. Why would two wires be shorted in this circuit?
Two green wires shorted together and grounded could be a result of a short
or overload in one circuit that melts the insulation in the wiring harness
to short the two wires together and to some point on the chassis at the
same time. But that sort of a short does not usually clear up just by
moving the wires about.
Not having continuity doesn't sound right. If the two wires are both
grounded they will abviously have continuity between them. The only way
they don't have continuity from one end to the other is if they are broken
or cut, in which case they probably wouldn't work again after just a little
fiddling. Or there may be a loose connector somewhere in the middle of the
wire run that you are overlooking, but this is not likely to affect both
wires exactly the same before and after the fiddling. Too many coiincidences.
Are you sure you are checking continuity correcty? Maybe you should try
disconnecting both ends of the wire when checking for a short to ground, as
a connection to an electric motor can have a very low resistance when the
motor is not running. Also check for continuity with the meter test leads
on opposite ends of the same wire. When multiple green wires go through a
harness it's hard to say which is which where they emerge from the harness
somewhere else.
>I cleaned the terminals to all the affected accessories
Corroded terminals do not generally cause shorts, but they could have been
touching something the was grounded before your fiddling. Again, not
likely to have exactly the same affect any two wires before and after.
>and removed the voltage stabilizer (according to Moss, not supposed to be
>one on the 67, but there was). I sanded the case of the stablilizer and
>where it mounts to create a better ground and lowered it where I could get
>to it the better the next time.
That could (possibly) have accounted for a short to the body in one green
wire at the prior mounting location, but probably not affecting two wires.
>This fixed (temporarily?) the problem, although I don't know which one was
>the direct cause since I didn't want to blow any more than the 5 fuses I'd
>already blown
I have a sneaking suspicion that you have not seen the last of this
problem. Perhaps it's a bare wire that was cut on the edge of sheet metal
where it pases through the firewall, and the short is disturbed
(temporarily) when you move the wire. If it happens again, start over and
be sure you check the three different green wires individually for short to
ground (and not possibly checking the same one twice?). Meanwhile, keep
some more fuses handy.
Barney Gaylord
1958 MGA with an attitude
http://www,ntsource.com/~barneymg
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