Tracking Down Battery Drain

tr7driver

Member
Sep 5, 2006
117
3
19
Illinois
I spent a good part of Sunday afternoon trying to track down a parasitic key-off battery drain on my car. (05 GT convertible -- The only aftermarket electrical mod is sequential tail lights, car is 100% stock) After charging the battery overnight with the ground cable disconnected from the car, I connected an amp meter in series, with the ground on the battery and the red lead on the end of the cable.

Initially, it was showing a 8.5 amp drawdown (amp meter set in the 20A range). I realized that each time I reconnected the amp meter, it started complied the circuit and set off a series of actions, like the cd shuffle mode, interior lights, ect. After giving it a few minutes to calm down, the draw fell to 2.5 amps. Then I started to pull the relays and fuses, one at a time. Pulling one fuse, marked smart junction box feed #6, caused the draw to fall to 1.5 amps. I reinstalled it and the draw stayed at 1.5 amps I switched it with another fuse and the draw stayed at the rest of the day. I paid special attention to the fuses under the smart junction box, but they showed no change in the draw.

I pulled every fuse and relay both under the hood and in the box below the smart junction box, but 1.5 was what the meter showed the rest of the day, no matter what I did. When I came back to the fuse that produced the first reaction, I saw no change.

What should the battery draw be? I’m thinking .5 amp range.

Any suggestions for additional tests or where else to look or another test methods? I disconnected the suspect radio fuse and the fuses for the shaker 500 amp, but no noticeable change there.

What should the battery draw be? I’m thinking .5 amp range.

Any suggestions for additional tests or where else to look or another test methods? I disconnected the suspect radio fuse and the fuses for the shaker 500 amp, but no noticeable change there.
 
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The red security light that flashes? I had a battery problem, I charged it and just started shutting off the radio manually(pushing the volume button), and the battery has been fine ever since then. More or less just needed charging, but I have read in numerous threads that the Shaker is the problem. SO I am getting into the practice of just turning it off.
 
Follow up

I went into a local high-end audio shop Monday and discussed the issue with them. They told me that some Ford computers can continue to draw a high amperage for up to an hour after the car is shut down, and opening the door or trunk could restart the hour cycle. So to do a valid test, I should wait an hour after the car is shut down and undisturbed to do any testing.

They also told me it is normal for a CD changer to cycle when power is first applied, even if it is turned off.

So, I let the car sit for a day and went through the fuse pulling routine again. This time, when I pulled the "radio" fuse, the draw dropped from 1.5 amps to .15 amp. I still think that draw is a little high, but it is an improvement. I can't seem to find a value for "normal" key-off power draw for a stang, but some "generic" levels I've seen on the web show about 0.05 Amp.

I pulled the fuse and let the car sit a day. Pulling the fuses for the amplifiers didn't cause a drop, but I yanked them out anyway. After sitting on day, the car started right up when I tested it last night.

I do make a point to turn the radio off before I shut the key off, so maybe there is something going on with my radio. I guess I'll soon be looking at repairing or replacing it.

Any recommendations for replacement units that plug and play? I may start a new thread for that question once I do a little more research.
 
I have seen some people throwing in some nice 7" touchscreen deals, Im not an audio guy at all...but they look cool.

I have seen a few that are made by pioneer, with the 7" touchscreen etc. etc. I would go that route, its looks just plain cool!
 
1.5A is definately pretty high, and it looks like you've got it narrowed down to the Skipper 500.

Do you have an alarm system? .15A is pretty reasonable, especially if you have an alarm system (factory or aftermarket).

As far as replacing the Skipper 500, go with an aftermarket system and don't look back. The sound quality, even using the stock speakers and amps will be unbelievable. Plus you have flexibility of options (iPod, Navigation, DVD, Bluetooth, etc.) I installed a Pioneer AVIC D3 and I LOVE it. Eventually I will be upgrading to a newer AVIC unit. Be aware that the stock amps use a 5 volt trigger signal to turn them on vs the standard 12V trigger signal. You will need to use a 5 volt regulator in line with the amp trigger wires. Instructions are here for AVIC units, but they would be the same for any after market head unit:

http://www.stangnet.com/mustang-forums/736028-pioneer-avic-d3-installation-write-up.html
 
update, problem found

While my daughter was backing the stang out of the garage I noticed one of the tail lamps was out. I switched the bulbs around and the same lamp position was still out. Following the wire into the harness I found a worn spot on the insulation that must have been touching the sheet metal. Taped it up and now the amp meter shows .02 amps with the radio plugged in and all the fuses in place.

One note, the audio shop guy was right that the computer will draw current after the car is shut down, in my case about 35 min. Also, when I put the amp meter in series with the battery cable, it wakes up the computer as well, so wait a while after hooking up an amp meter to track down electrical issues on your stang or use an inductive meter.
 
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I had the issue with the battery draining after the car sat for a couple of days. My fix was turn the key off and manually power off the radio before opening the door. Never had a batteru issue after using that method.
 
Hey y'all! I know this thread is really old but if anyone is still having this trouble the answer is.... The "Smart Junction Box". But it's not very smart. Ford is notorious for stupid things and this is one. There are grommet seals on your cowl under the windshield that most likely have a leak and this is the reason you are having issues. The water leaks INTO the car and shorts the SJB out. I have this problem as well. I had a tail light that stayed on, battery drains in a little over an hour, and most likely other things happen that I'm not aware of yet. But, it IS your SJB. Replace it. Sadly, they are about $350. But it's worth it. And buy the grommets too. They will close $5 each but you need 10. There is a great video on YouTube for changing these. It should be one of the first ones that pop up. Damn ford.
 
I think I have the same issue I installed a sequential tail light kit on Christmas and like 2 days later the car wouldn't start and I've been having issues ever since I'm getting mad now because it Spring/Summer and about to be riding season.
 
update, problem found

While my daughter was backing the stang out of the garage I noticed one of the tail lamps was out. I switched the bulbs around and the same lamp position was still out. Following the wire into the harness I found a worn spot on the insulation that must have been touching the sheet metal. Taped it up and now the amp meter shows .02 amps with the radio plugged in and all the fuses in place.

One note, the audio shop guy was right that the computer will draw current after the car is shut down, in my case about 35 min. Also, when I put the amp meter in series with the battery cable, it wakes up the computer as well, so wait a while after hooking up an amp meter to track down electrical issues on your stang or use an inductive meter.


did you find out a solution?
 
Ive heard of oem stereos causing this issue. It has something to do with the security. Ive had mine 5 years and gone through 2. But I live were it hits 120 frequently, 2 -3 years is the norm. Unless you get lucky.
 
I'm trying that now . I've been cutting the radio off before I get out even though it automatically turns off with key. I rather try all the Free/Cheap stuff before I have to go to the shop LOL