I have a1988 convertible with the 4 + 3 tranny. If I didn't drive it
for about a week, the battery was dead. I thought it might be a
defective battery so I replaced it and had my mechanic check it out.
He reported that the charging system is OK and that there is only a
17ma draw when parked, which is acceptable. After a week without
driving it, it is dead again. Any ideas???
==================I second the Battery Tendar ...but I had the same problem...with the
same cause in both my 79 and in my 95 with the under hood light not
always shutting off... disconnected both and no more dead batteries...
PS...I still use the Battery Tenders on all my cars when I know I will
not be driving them for a week or more...and of course over the
Before using the battery tenders I was replacing at least 2 batteries
every spring...after the cars were stored during the winter...
64 72 & 98 Convertibles
76 & 79 Coupes
Yeah, here's another thought. I had the C4 laid up since the first of
the month and fired it up yesterday. Was ready to pull out the charger
but checked the batt voltage before I turned the key. (11.3 volts --
out of a four year old battery). I then thought back to this thread.
Several years ago, my '89 developed a high resistance short (to ground)
in the *ground* wire to the spare tire lamp and this was bleeding the
This circuit is a bit unusual since the 'hot' side of the spare tire
lamp is hot at all times. The ground is provided by the interior light
circuit. In the '89 there are enough lamps on this circuit that a
partial ground can draw a lot of milliamps but the lamps won't glow.
The infamous delay timer also plays in this sandbox so it ain't easy to
troubleshoot. You might take a close look at the wiring near the spare
tire. Seems strange that this wouldn't have showed up during the
mechanic's stray current check -- might be intermittent.
My 1984 battery would die after a week or so..no number of replacement
batteries or electrical checks could cure it...I then
en changed the ceasefire system to a 1990 TPI system with a new 1990
computer...I never had a dead battery again..even after a couple of months
of storage...the only elect item changed was the computer ecm...so I have
been told the problem must have been computer related..????
This seems to be a very very common problem with C-4 Cars...and there does
not appear to be any single solution to it....it drives everyone nuts..can't
even leave your car at the airport and expect it to start after a week...sad
situation..but then it is a GM product so what do you expect.
Many yrs. ago I got tired of chasing electrons on my '75 to find the reason
for my dead/weak battery. I added a battery disconnect to the battery and
simply disconnect the system while not driving. End of problem. They are a
cheap fix when you run out of patience/ideas.
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On his '75 that would work, I don't think there is anything with memory.
But on a C$ that would be a pain, like you said.
Yes....Mine is doing the same thing....the short is in the dashboard
cluster. I put a brand new battery in it this year, and within a week I
went out to start it, and nothing....A mechanic told me he tracked it down
to the circuit board in the dash....not sure if that is your situation, but
it was a common problem...
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