On Thu, 14 Mar 2013 13:49:24 -0700, "David Farber"
wrote:

wrote:
David Farber wrote:
With the unit powered on and no load or signal, the draw was about
545ma.

About 6.5 watts... that seems reasonable.

In standby mode, the current draw was about 4.5ma.

This shouldn't kill a car battery in good condition. I have heard
various numbers for the acceptable "key off" draw on a car battery but
20 mA is usually somewhere in the ballpark. This is for everything in
the car - the radio station memory, a clock, anything the ECU needs,
security system, etc. 20 mA is 0.48 amp-hours a day, or 6.7 Ah in two
weeks. A car battery is very very roughly 50 Ah plus or minus [1];
with
6.7 Ah gone it will probably still start the car. ("Airport time" is
one name for this - you should be able to leave the car at the airport
for X amount of time and it should still start when you get back.)

I'm going to reinstall the radio tomorrow and see how these numbers
compare to the current drain from the car battery.

You might poke at the harness side of the connectors with a 12 V test
light before you reinstall the radio. Maybe it's not getting the
message that it could go into standby - short to battery power on the
"hot in run" line?

If this car has any aftermarket stereo equipment wired to the factory
head end, you can assume this was done incorrectly and be right about
half the time. Other sources of automotive electrical fun include
aftermarket trailer hookups and driving lights.

If the car has a trunk light or underhood light, look to see if it's
shutting off correctly when the trunk/hood is closed. This can be
a hard-to-catch source of battery drain.

Matt Roberds

[1] Yes, I know they are not rated by their manufacturer or sold this
way. If you use one like a deep-cycle battery instead of a
starting battery, you get roughly 50 Ah. Yes, it's not a good
idea to use a starting battery like a deep-cycle. The 50 Ah
number is just there as a reference for things like this.

This turned out to be quite the adventure. I got a little more information
from the owner. The problem started when the parking brake was pushed down.
(It uses a foot pedal for the parking brake)

That's actually a better design. If your hydraulic brakes fail, hold
the foot brake release handle so the brakes don't lock and then use
your foot to apply the "hand brake", "emergency brake". . You can
use it like the regular foot brake. I hate the hand brake between
the seats.

. Somehow her foot dislodged the
connector going to something around the clutch pedal shaft. It has six
terminals and I'm guessing it's some sort of sensor that detects the
position of the clutch so you can start the car? I removed the plug and
checked for damage. It looked fine. I did take a reading of the battery
current before I put the radio back in with everything off before I started
troubleshooting. The reading was 0. Then when I was using my meter later on
I noticed that the DCV button was pressed in and not the DCAmps. At some
point I measured .22A from the battery. I put the radio fuse back in
(somebody had pulled it out so the radio wouldn't be draining the system)

On some cars there are 3 fuses for the radio. GM, for example. I
think you talked aobut this before. One for the clock, so it doesn't
stop when the car is turned off, one for the dash lights,, and one for
the radio itself.

and measured the current. I jumped two about 2 amps. I wasn't writing this

When you're miy age, you'll write it down. But I give you a lot of
credit for using a meter. It's hard to get anyone to use a meter.
(Anyone who doesn't read SER, at leat)

stuff down but I think that's what it was. Next I pulled the radio out again
and left the fuse in. It was still reading too high. Then I pulled the fuse
out and it was still reading too high. Huh?

I know that feeling. When I was 19, the first week I had my '50 olds,
the battery was dead every monring and I had to take my mothers car.

Short, Doconnect, Short Disconnect, Short, Disconnect, no short!!!
Reconnect last disconnected wire. No short, Reconnect wire before
that , No short, Reconnect wire before that. No short.

Up and down, up and down, 3 or 4 levels, 3 or 4 found tirps, and in
1950 there were no quick disconnects.

Finally found it. Glove box light. Every time I got close, I opened
the glove box to get something and if it was closed well before, I
closed it badly. If it was closed badly, I closed it well. That was
also what drained the battery.

:I proceeded to turn "off"
(though I can't specifically remember that it was even lighting up) the dome
light by moving the dome switch to one side. It's a three position switch so
I figured one of the other choices was always off and the other position
would be always on. The light didn't come on so I figured I made the right
choice. Later on I found out that those other two positions of the switch
were for, always on left lamp and always on right lamp. All these little
details that you don't think about beforehand.

So now both doors are closed to make sure the dome lamp won't come on. The
radio and Fuse 29 is removed. The current from the battery is in the 1.8 amp
range. Great. I've done nothing but inspect the system and things are
getting worse. Then I looked at the schematic
http://webpages.charter.net/mrfixite...ck_Fuse_29.mht
There were four other lines that distributed standby power to the car. They
were the cigarette lighter, flasher, instrument panel, and generic
electronic module / central timer module. I pulled those fuses one at a time
and went back and measured the current. After pulling the lighter fuse, the
current drop to about .8A.

Snmeone may have wired something to the cig lighter circuit. I use
that alot because I almost never use the lighter, so it doesn't
interfere with add-ons.

Pulling the flasher fuse had no effect. Pulling
the instrument panel fuse lowered it a bit more, and then pulling the last
fuse dropped it down to near nothing. I put on my magnifying glasses and
took a good look at the cigarette lighter. There was some rust or corrosion
in there. By the way, the receptacle itself was not covered/protected so it
made sense that it was getting to look a bit rusty. I took a sharp ended
pick tool and started to scrape away at the corrosion. I put the fuse back
in and the current didn't spike up. In fact with all the fuses put back in,
the current leveled off at .22A. I didn't know if this was an acceptable

If you have a decimal point, please put a zero in front of it. With
my monitor, it's about the only way I can tell it's there. Right now
it looks like 22 amps.

reading or not. One of my friends was visiting with me so I asked him if I
could remove the battery cable from his 2001 Honda and check how much
current was flowing from his battery in standby. It was identical .22A. I'm
still waiting to hear back from the owner if the battery made it through the
night or it had to be jump started. That's usually good news when somebody
doesn't call you back when you ask them if your repair went well, isn't it?

I suppose so.

Thanks for your reply.