zahid@serval.sps.mot.com (Zahid Ahsanullah) writes:
> My '68 E-type coupe has been draining the battery constantly and last night
> it just died. [...] I figure that I could hook up an ammeter to the battery
> and start removing fuses one after another until I get the circuit that is
> shorting or leaking. For this system to work, there should be no article
> that drains the same amount as the short as I wouldn't be able to tell the
> short from the normal operation.
This makes sense; in actual fact, if everything is shut down, you should find
little or no current flow on all circuits. Initially, you should find the sus-
picious power drain with all fuses in place, then pull fuses one at a time un-
til the current flow abruptly drops. If you can't measure an appreciable cur-
rent flow to begin with, perhaps you have a faulty battery or a grounded lead
between the battery and the fuse block. Check your battery cable routing, too.
> So does anyone have suggestion on what loads down the battery constantly
> other than a clock?
Unless you have a recent-vintage quartz clock (i.e. the sweep-second hand
either glides smoothly or ticks in precisely one-second increments), the
clock does not exert a constant drain. The old ones have an electro-mechanical
winder mechanism that clunks a solenoid once about every 90 seconds or so. It
should tick merrily with no drain whatsoever for 90 seconds, followed by an
obvious single *click!* as it rewinds itself.
Pop-out cigarette lighters are a common source of trouble. They can make a
partial contact capable of draining the battery without generating sufficient
heat to relax their bimetallic springs and pop the element out. Check that
yours are not stuck in. If in doubt, pull them out for the night.
Also look for courtesy lights and map lights that may not be properly switched
off. In particular, the chrome bullet-shaped map lights on pivoting goosenecks
can work loose and allow current to leak even when in the Off position (which
is usually when the gooseneck is stowed by swinging to one side of its base).
The light can droop just enough to touch its grounded gooseneck at the edge
of the insulating center piece. Been there, done that. :-(
> If all the fuses are removed, should the current drain be almost negligable
> i.e. in microamps?
Yup. If you've removed every single fuse, you should have a dead car. Check
for in-line fuses as well as those in the fuseblock. Hopefully an E-type owner
can direct you to where those are. Good luck!
Andrew C. Green
Datalogics, Inc. Internet: acg@dlogics.com
441 W. Huron UUCP: ..!uunet!dlogics!acg
Chicago, IL 60610 FAX: (312) 266-4473
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