Battery Drain - How to I trace?

[gibbs1820]

Battery Drain - How to I trace? Updated with more questions.

I have a 97 Mustang that if I leave sitting for 4 days my battery will drain and I will need a jump start. If I run it day after day I don't have an issue. The car will start up every time.

What could be draining the battery? I don't have an after market radio or anything like that.

What are the steps to trace something like this?
I've already replace the battery and checked the cables.

 

[jegg]

I am assuming you know how to use a volt meter. So, if you do, check the voltage on every fuse to narrow it down. CHeck voltage on the fuses when everything in the car is off. If you get a reading on any of the fuses when you should not be then you have found the drain. If you have no readings on any of the fuses....then...well....idk

 

[wmburns]

Checking for voltage at the fuse is of little help because there are so many "always on" circuits. In additon, a voltage check does not tell how much current the circuit is using.

Install an amp meter (shut) in series with the battery. Read and record the power draw. Allow the car to set for 30 minutes, record the current.

Now pull each fuse one at a time. Record the amount the amps drop. Post which circuits had the greatest drop.

Locating power draws is a difficult and time consuming process. Take your time and do the steps.

Just to check, you don't have a speedcal or cell phone charger, or audio equipment? What about the top of the battery? Is it clean?

 

[ProCharger GT]

I had the same problem; thought it was the BAP, mis-wiring, etc - ended up that something in my stock head unit shorted out, so I just pulled the fuse. Not saying that the radio is the culprit in your case, but it was a real pain in the rear end. As mentioned above, pulling fuses is what you'll need to do to be certain.

 

[Midnight2V]

Just out of curiosity, how old is the battery? If its past 5 years, it may simply be going bad and it needs to be replaced. Some models are only good for three.

 

[007]

Try leaving charging the battery and leaving it completely disconnected. Mine drained on its own! Internal short on a battery 6 months old.

New battery - no issues.

 

[GDawg]

Check your alternator too. How many times have you deep cycled that battery?

 

[Mel96GT]

I had a similar problem, turned out to be the power seat toggle switch was bad. It burned up the wiring and motor under the drivers seat, actually it would have burned up the car but the fuse blew. Pull the 30 amp fuse for the power seat, it is located in the fuse box under the hood. See what happens. Let us know.

 

[gibbs1820]

Ok I've checked the battery draw with my meter. It is showing .19 amps.
I went through all the fuses. When I pull the fuse under the hood for the radio it drops to .06amps.

What is the normal battery drain for the radio?

The only other fuse that made a difference was the one that supports the instrument fuse panel inside the car.

I tried to pull the radio head unit, is there a secret to this? I could pull it almost all the way out, but the wiring seems extremely short and I didn't want to pull out any wires. Could my radio head unit be the problem? It is the factory unit with the tap player and then a unit below with the CD player.

Please advise. Thanks

 

[gibbs1820]

Update:

Pulled the radio unit out as well as the CD player so they were both disconnected.

Under the hood fuse labeled "Audio" is a 25 amp fuse. Measured with meter with that fuse installed and radio fully disconnected it was still reading .12 amps

I reinstalled the radio and pulled the fuse. Radio had power, but with fuse pulled there wasn't any sound coming from the speakers. I re-installed fuse and I had sound from all 4 speakers again.

Radio, CD, and Tape all function properly. Not sure what to do next. Ideas?

 

[Mel96GT]

Did you pull the 30 amp fuze for the power seat? BTW, does your power seat still work?

 

[gibbs1820]

Power seat still works. Only change in amps happened when I pulled under Hood fuses labeled "radio" and "I/P"