"toptech" <wenken2@aol.com> wrote:
>i have a 2000 chevy express 3500 van,, if i leave it parked for two days
>the battery goes dead,, after battery replacement the problem is still
>there so i did some checking and found that i have a .054 millieamp draw
>on the battery.. according to the dealer ther should only be .025 milliamp
>draw.. so i removed fuses till i found the juice sucker,, it turned out to
>be the plain jane radieo mem. fuse #19so i replaced the radieo 2 days
>later, dead battery,,, any ideas??? stumped
I worked on a friend's Cutlass that had the same symptoms, but
intermittently. Every 1-3 days, the battery would be dead after an
overnight sit. Pulling the battery cable off and inserting a digital meter
in current mode, and there was less than 10mA flowing to run the
radio-clock. That will never run the battery down in a day or two or even a
week. Dome lights, trunk lights, and glove box lights were all suspect, but
not the problem I had
After six days of experiments, I used a clamp-on DC ammeter (Fluke made one
that used a Hall-effect sensor to read DC amps - normal clamp on ammeters
can't do DC, just AC) to read the steady-state current draw when the car
was turned off. The ammeter read 1.5 - 2A about every third time I turned
off the car, not zero. The reason to use the clamp-on ammeter instead of
the 10A range of the Fluke 77 DVM was that I wanted to be able to start the
car, then read the turned off current after the ignition switch was off.
The high starter current would have fried the 10Amp range shunt resistor
inside the Fluke 77 meter.
With a clamp on ammeter, there is no shunt resistor to fry, and the reading
was the true current flow in the battery wire. (I'm an electrical engineer
for a day job.
The problem with the car was the engine computer wasn't reliably going into
sleep shutdown mode after the ignition was turned off. I could have found
that by doing wholesale component swapping, or by spending more money on
parts. That's not elegant. When the computer didn't go into sleep mode, it
was sitting there running 1-2 amps on its own, thinking that the ignition
key was on and the car was about to start.
Swapped the computer ($75 exchange at the local parts place) and the
problem went away for good.
Your problem might still be a dome or glove box light you haven't found
yet. But if you have a buddy with a similar vehicle, you might try
exchanging engine computers with him and see what happens.
--
Bill "the Roadie" Carton