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Battery draining

  • Thread starter Thread starter LucksMyName
  • Start date Start date Dec 13, 2019
L

LucksMyName

New Member
Aug 17, 2019
3
0
1
arizona
Dec 13, 2019
#1
  • Dec 13, 2019
  • #1
Recently got myself a 00 mustang gt from a family member without the car remote and keys as he lost it, so the alarm been on(Anti theft light blinks). I replaced the keys and can drive it no problem but the battery dies within a day without use.(bought new battery same issue). Im wondering if its the alarm system could be whats causing the problem?
 
S

Sluggie24

Active Member
Apr 8, 2017
135
22
28
Dec 14, 2019
#2
  • Dec 14, 2019
  • #2
There is an electrical draw in the system. The easiest way to find it will be to unhook the negative battery cable and hook up a multimeter between the terminal and the battery post. Set the meter to read amps. A normal memory draw will be below .5A when the car is off, key out and all doors closed. (Usually have to wait 1-2 minutes to ensure all modules have had time to power down.

First see how large the draw is. Likely a few amps. Start under the hood unplugging fuses one at a time and see if any single fuse being removed causes the reading to drop to below .5A. If none do try the inside fuses. The circuit that fuse powers is the problem. You will have to see what is powered by that circuit and disconnect one item at a time from that circuit to figure out where the problem is.

If you have to work inside the car to do this make sure you close the door latches with the doors open so the car doesn't see them as open as this would cause a draw and change your readings. The door latches can be closed using a screwdriver or similar tool.
 
Reactions: 2Blue2

wmburns

SN Certified Technician
Aug 14, 2009
5,892
514
204
Houston Texas
Dec 15, 2019
#3
  • Dec 15, 2019
  • #3
Does the theft light blink slow (about once every three seconds) or fast (once per second)?

If the theft light blinks slow, this means that the system is working as expected and is standing by. Not your problem. Look elsewhere.
 

DarthStang2003

Member
Jun 30, 2019
38
9
18
South Florida
Jan 4, 2020
#4
  • Jan 4, 2020
  • #4
wmburns said:
Does the theft light blink slow (about once every three seconds) or fast (once per second)?

If the theft light blinks slow, this means that the system is working as expected and is standing by. Not your problem. Look elsewhere.
Click to expand...
What happens if it’s fast? Mine sometimes is fast or steady on. I have an 03 GT, my lights pulse sometimes too, not every time. Shortly after I got the car last April I had to replace the alternator. Any suggestions? (Alternator is for 01 Bullitt cause that’s the Intake manifold I have on the car.)
 

wmburns

SN Certified Technician
Aug 14, 2009
5,892
514
204
Houston Texas
Jan 4, 2020
#5
  • Jan 4, 2020
  • #5
If a slow blink theft light means it's ok, what do you "think" a fast blink or on solid means?

Check out the crank with no start check list.

1996+ Crank with no start check list

1997 mustang wont ignite

Hello lets start with I have a 97 mustang gt v8 standard I had new engine transmission ect put all new well last month i shut the car off and had no power at all bought a new battery and alternator got all power back but it wont ignite brought to mechnic for a month all sensors codes ect are fine
www.allfordmustangs.com

Howto perform charging system voltage drop test

Howto perform charging system voltage drop test

To anyone else reading any of my posts I usually include the line: Today's cars simply will not run right without a strong battery and charging system! Cut corners here at your own risk I'm a big believer in starting with the basics. As such I...
www.stangnet.com

If you are really trying to learn how to trouble shoot your PCM, here's some information on something that will take your trouble shooting to the next level.

ForScan ODB2 scanner w ELM327 USB

ForScan ODB2 scanner w ELM327 USB

While working on your car have you ever wanted: to find an ODB2 operational PID value (say fuel pressure or MAF)? How about graph a PID value over time? Or compare multiple PID's over time? Access a bi-directional PCM control such as test a...
www.stangnet.com
 
Reactions: DarthStang2003

DarthStang2003

Member
Jun 30, 2019
38
9
18
South Florida
Jan 4, 2020
#6
  • Jan 4, 2020
  • #6
wmburns said:
If a slow blink theft light means it's ok, what do you "think" a fast blink or on solid means?

Check out the crank with no start check list.

1996+ Crank with no start check list

1997 mustang wont ignite

Hello lets start with I have a 97 mustang gt v8 standard I had new engine transmission ect put all new well last month i shut the car off and had no power at all bought a new battery and alternator got all power back but it wont ignite brought to mechnic for a month all sensors codes ect are fine
www.allfordmustangs.com

Howto perform charging system voltage drop test

Howto perform charging system voltage drop test

To anyone else reading any of my posts I usually include the line: Today's cars simply will not run right without a strong battery and charging system! Cut corners here at your own risk I'm a big believer in starting with the basics. As such I...
www.stangnet.com

If you are really trying to learn how to trouble shoot your PCM, here's some information on something that will take your trouble shooting to the next level.

ForScan ODB2 scanner w ELM327 USB

ForScan ODB2 scanner w ELM327 USB

While working on your car have you ever wanted: to find an ODB2 operational PID value (say fuel pressure or MAF)? How about graph a PID value over time? Or compare multiple PID's over time? Access a bi-directional PCM control such as test a...
www.stangnet.com
Click to expand...
Thank you!
 
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