Bracket Talk
Can't find source of amp drain

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October 27, 2019, 04:24 PM
Ron Gusack
Can't find source of amp drain
2004 Buick Park Avenue drawing about 1.4 amps with everything off except clock. Pulled all fuses and relays one at a time with no change. There are 4 different fuse boxes and we hit all of them. Could it be the alternator or starter solenoid?
October 27, 2019, 04:40 PM
HR3377
probably the alt
October 27, 2019, 04:45 PM
57 Vette
Disconnect the Alternator,possible shorted diode.

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October 27, 2019, 05:21 PM
fasterat
I’ve spent more time than I ever wanted to chasing parasitic drains! Is it constant? I had a Ford that behaved like an intermittent parasitic drain. Girlfriends sons car. Has never been accused of being a go getter so I tried to involve him. Long story short, I tested battery as good, same with 3 national chain auto parts stores. On a win I changed battery and car has been fine since. If you are just using a test light and pulling fuses looking for the problem, that’s not thorough enough. I open all doors, windows, hood, trunk,anything with a spring type switch and tape them closed. Disconnect battery and clamp cables together for minimum of 4 hours. Gotta discharge all capacitors. Then using meter with dc milli amps detecting ability and wiring diagrams check all circuits. Or change battery!
October 27, 2019, 06:03 PM
Eman
Since you say it's a 1.4 amp draw I guess you're using a DVOM not a test light. It could be the alt. Be sure to use a bridge and allow everything to time out before opening the bridge and allowing current through the meter. It does take some time to let everything time out and power down.
October 28, 2019, 09:56 AM
Ron Gusack
I don't know what a bridge is.

This message has been edited. Last edited by: Ron Gusack,
October 28, 2019, 10:06 AM
Eman
A bridge is more or less a switch. I use one of those battery disconnects with the big green knob. You hook everything up with the knob tight and start the car to make sure everything is working properly. You then shut the car off and hook the 2 leads of your amp meter across the switch. Then you loosen the knob,or open the switch so any current flows through the meter. You can then see the draw and you then have to wait to see if it drops as things power down. 30 milliamp is usually the draw once everything powers down that is acceptable maximum.
https://www.harborfreight.com/...ct-switch-97853.html
October 28, 2019, 11:04 AM
Ron Gusack
That's a good idea Eman, thanks. I'm using a DVOM with a amp clamp. Battery voltage was at 4.5 this morning and there was no amp draw. We charged battery to 12.1 volts and measured .034 amp draw. Ran the engine for a about 5 minutes and after cutting it off amp draw was never higher than .06. Current battery voltage is 12.01. I'll let it sit and check again.

If 30 milliamps is the highest acceptable, we're still in trouble.
October 30, 2019, 03:05 PM
Triple Nickel
If you have a 1 wire alternator its absolutely the alternator. Connect it with a solenoid on the main wire to the alternator with a switch to arm the solenoid. This fixed my problem right away. 1 wire alternators remain hot until all voltage is removed from the main charging post.
October 30, 2019, 04:42 PM
sc3912
A battery that is only reading 12-12.1 volts is only around 30% charged. I would try to fully charge the battery, and then run your draw test. There are charts on the internet that show a batteries relative state of charge based on the voltmeter reading.
November 03, 2019, 08:43 PM
GEAR_HEAD
As said battery very low on state of charge,
I would replace it first, then move to testing. QUOTE]Originally posted by sc3912:
A battery that is only reading 12-12.1 volts is only around 30% charged. I would try to fully charge the battery, and then run your draw test. There are charts on the internet that show a batteries relative state of charge based on the voltmeter reading.[/QUOTE]
November 04, 2019, 05:28 AM
BJs Wild Ride
I worked on a similar era Buick riviera. There was about 3 or 4 fuses that had to be removed from the under dash panel at the same time to kill the drain. It acted like either a instrument panel control module or a body control module was bad but the dealer had already replaced both at a cost of thousands of dollars to this little old lady. I ended up installing a switch that turned off the problem circuits. She couldn’t use radio presets but was otherwise satisfied as she couldn’t spend any more money on it.
November 04, 2019, 04:00 PM
Ron Gusack
Update: Put a new battery in it and read amps on positive and negative side. Positive side read.02 amps and negative was .07 amps. I don't understand why it reads different but .07 seems high and creates a party strong spark when attaching the cable.

We pulled fuses from the under dash box but did them one at a time. Maybe worth a look.

This is a totally stock car so not a one wire alternator. When I disconnected the alternator, I only took the main cable off and not the field wires or whatever they are.
November 04, 2019, 09:30 PM
Eman
You're always going to get a spark, you are powering up everything. That's the reason for the bridge. The small wires on the alternator need to be unplugged.
November 05, 2019, 04:37 AM
Ron Ciglar
Use a Raytek (Infrared thermometer temperature gun) after the vehicle sits overnight to look for something warmer than everything else (starter, alt, wiper motor etc.) including each relay and fuse. If currant is running through it then its creating heat.
November 05, 2019, 08:50 AM
Ron Gusack
Thanks Eman. Does it make sense that the amp reading is different on the two cables?

I'll use my temp gun to shoot at stuff if I can't find it by unplugging stuff. I wouldn't think a small drain would create much heat on a starter case.