Did I do this right?
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Freshman User
Joined: Oct 2004
Posts: 33
Likes: 0
Did I do this right?
About a week ago I started a thread on my battery going dead and it happened again. So I disconnected the neg. terminal and clipped a wire to the neg. batt. post, then to a 12 volt light and back to the terminal. Now if there is no draw the light shouldn't go on, right? Well it did, so I started pulling the fuses and after pulling fuse 35 (insturment cluster) it went out. But, my radio suddenly turned on. Why would that happen? I'm so confused!! Is it the negative terminal that gets disconnected or the positive?
Junior User
Joined: Oct 2010
Posts: 59
Likes: 0
From: Chicago
Your battery must have a reasonable charge for this test - it won't work if your battery is dead. Quick proof - if your dome light operates normally, you're fine. My truck wouldn't start and the batteries were down to 5.5 volts so I put a charger on the batteries overnight. They are now 12.2 V. When I started the truck the voltage went to 14.3 V so the alternator is working.
3. Check to make sure ALL loads are turned off. Unplug anything you may have plugged into the cigarette lighter. Remove your keys from the ignition. Close all doors so the dome lights are off.
4. Disconnect the thick positive (Red) cable that goes down to the starter.
5. To start make sure your meter is set to the 10 amp DC range. Some meters have a special connector for the red probe when you are reading current. You can either do this next step by just holding the meter probes to their respective contact points (you won't get a shock from 12 volts) or you can use probes with alligator clips to snap them in place so your hands are free to do something else.
6. Connect the positive probe to the battery Polarity on digital meters doesn't matter because they are autosensing.
7. Connect the negative probe to the red cable that is still connected to the vehicle. Make sure this cable and your probe do not touch ground.
8. If there is a severe current draw (more than 10 amps) it will either pop a fuse in your meter or destroy it outright. That's why you need to test for a short, otherwise, your meter should now be reading the current drain on your battery.
9. If your vehicle has an alarm system or remote locks, the current draw may be around 2-3 amps for a few minutes after you last close the door. This is normal. If you're not sure, wait at least 20 minutes after you last open or close a door before you take a reading.
10. If everything is normal, you will read less than 35 milliamps, or .035 amps. If the current drain is higher than that, you need to find out what is draining your batteries: You can start by pulling fuses until the load goes away. If that doesn't reduce the draw, you need to look for a wire that is corroded or frayed.
This is how we do it at Ford and Land Rover.
Good Luck
3. Check to make sure ALL loads are turned off. Unplug anything you may have plugged into the cigarette lighter. Remove your keys from the ignition. Close all doors so the dome lights are off.
4. Disconnect the thick positive (Red) cable that goes down to the starter.
5. To start make sure your meter is set to the 10 amp DC range. Some meters have a special connector for the red probe when you are reading current. You can either do this next step by just holding the meter probes to their respective contact points (you won't get a shock from 12 volts) or you can use probes with alligator clips to snap them in place so your hands are free to do something else.
6. Connect the positive probe to the battery Polarity on digital meters doesn't matter because they are autosensing.
7. Connect the negative probe to the red cable that is still connected to the vehicle. Make sure this cable and your probe do not touch ground.
8. If there is a severe current draw (more than 10 amps) it will either pop a fuse in your meter or destroy it outright. That's why you need to test for a short, otherwise, your meter should now be reading the current drain on your battery.
9. If your vehicle has an alarm system or remote locks, the current draw may be around 2-3 amps for a few minutes after you last close the door. This is normal. If you're not sure, wait at least 20 minutes after you last open or close a door before you take a reading.
10. If everything is normal, you will read less than 35 milliamps, or .035 amps. If the current drain is higher than that, you need to find out what is draining your batteries: You can start by pulling fuses until the load goes away. If that doesn't reduce the draw, you need to look for a wire that is corroded or frayed.
This is how we do it at Ford and Land Rover.
Good Luck
Postmaster
Joined: Apr 2005
Posts: 2,759
Likes: 0
From: round rock, tx
Your battery must have a reasonable charge for this test - it won't work if your battery is dead. Quick proof - if your dome light operates normally, you're fine. My truck wouldn't start and the batteries were down to 5.5 volts so I put a charger on the batteries overnight. They are now 12.2 V. When I started the truck the voltage went to 14.3 V so the alternator is working.
3. Check to make sure ALL loads are turned off. Unplug anything you may have plugged into the cigarette lighter. Remove your keys from the ignition. Close all doors so the dome lights are off.
4. Disconnect the thick positive (Red) cable that goes down to the starter.
5. To start make sure your meter is set to the 10 amp DC range. Some meters have a special connector for the red probe when you are reading current. You can either do this next step by just holding the meter probes to their respective contact points (you won't get a shock from 12 volts) or you can use probes with alligator clips to snap them in place so your hands are free to do something else.
6. Connect the positive probe to the battery Polarity on digital meters doesn't matter because they are autosensing.
7. Connect the negative probe to the red cable that is still connected to the vehicle. Make sure this cable and your probe do not touch ground.
8. If there is a severe current draw (more than 10 amps) it will either pop a fuse in your meter or destroy it outright. That's why you need to test for a short, otherwise, your meter should now be reading the current drain on your battery.
9. If your vehicle has an alarm system or remote locks, the current draw may be around 2-3 amps for a few minutes after you last close the door. This is normal. If you're not sure, wait at least 20 minutes after you last open or close a door before you take a reading.
10. If everything is normal, you will read less than 35 milliamps, or .035 amps. If the current drain is higher than that, you need to find out what is draining your batteries: You can start by pulling fuses until the load goes away. If that doesn't reduce the draw, you need to look for a wire that is corroded or frayed.
This is how we do it at Ford and Land Rover.
Good Luck
3. Check to make sure ALL loads are turned off. Unplug anything you may have plugged into the cigarette lighter. Remove your keys from the ignition. Close all doors so the dome lights are off.
4. Disconnect the thick positive (Red) cable that goes down to the starter.
5. To start make sure your meter is set to the 10 amp DC range. Some meters have a special connector for the red probe when you are reading current. You can either do this next step by just holding the meter probes to their respective contact points (you won't get a shock from 12 volts) or you can use probes with alligator clips to snap them in place so your hands are free to do something else.
6. Connect the positive probe to the battery Polarity on digital meters doesn't matter because they are autosensing.
7. Connect the negative probe to the red cable that is still connected to the vehicle. Make sure this cable and your probe do not touch ground.
8. If there is a severe current draw (more than 10 amps) it will either pop a fuse in your meter or destroy it outright. That's why you need to test for a short, otherwise, your meter should now be reading the current drain on your battery.
9. If your vehicle has an alarm system or remote locks, the current draw may be around 2-3 amps for a few minutes after you last close the door. This is normal. If you're not sure, wait at least 20 minutes after you last open or close a door before you take a reading.
10. If everything is normal, you will read less than 35 milliamps, or .035 amps. If the current drain is higher than that, you need to find out what is draining your batteries: You can start by pulling fuses until the load goes away. If that doesn't reduce the draw, you need to look for a wire that is corroded or frayed.
This is how we do it at Ford and Land Rover.
Good Luck
cubantech: I am having some real electrical issues with my 02'
Would you please IM me with your contact info
I would like to reach you to help me troubleshoot my continuing alternator deaths(3 in two years)
thanks
Post Fiend
Joined: Jul 2005
Posts: 6,127
Likes: 6
1. 350 to 800 milliamps is normal.
350 range is the "idle" current for the Body control Module.
800 milliamps is its "power on" state.
Alarms, etc. are on top.
Perfectly normal.
Tell me more about the alternators that keep frying.
Where did you get them, what electrical loads you are running in the vehicle, what shape is the batteries in (have they been load tested) etc.
I think you just need some magic..
Tell me what voltages you got when you did alternator diagnostics...
Did you replace the pigtail?
350 range is the "idle" current for the Body control Module.
800 milliamps is its "power on" state.
Alarms, etc. are on top.
Perfectly normal.
Tell me more about the alternators that keep frying.
Where did you get them, what electrical loads you are running in the vehicle, what shape is the batteries in (have they been load tested) etc.
I think you just need some magic..
Tell me what voltages you got when you did alternator diagnostics...
Did you replace the pigtail?
