Radio draining battery why?

[BIGV]

Ok I replaced the original oem battery 3 weeks ago because car was dead and figured it was time. Drove the car to my parents and back home about 300 miles. Then parked it for 3 weeks and the battery is dead again. I did an amp draw and it was pulling just under 2 amps. Started with the usual suspects and it is the radio. Pulled the fuse and amp draw dropped to .31 why did this happen I have not touched the radio. Is this an internal problem with the radio or an external one. Has anyone else ever had this problem before. I am thinking of just swapping the radio out and see if that fixes the problem. Also how long would a 2 amp draw take to kill the battery enough the car won't turn over.

 

[Wayneo]

It could just be the radio. Do you have any aftermarked speakers, amp or subs? If so I would double check the wiring because more then half the time a draw is caused by aftermarket parts or the alternator. I once had a fellow 03 cobra owner complaining about the same thing and he had wires running to a sub in the trunk and one of the wires was chaffed through behind the rear seat shorting to ground keeping the radio from going to sleep. If you didn't know modules take about a half an hour to actually turn complety off. If you just pulled the fuse it could also be anything else that is on that circuit that is causing the draw. You have to start by disconnecting everything on that circuit one at a time to isolate the draw.

 

[TVSCobra]

.31 is still too high. It should be around 20-50ma (.02 to .05 amps)after an hour the car should be "asleep". You may have something else that is "waking" the radio up or it could be a faulty radio. Any other aftermarket accessories?

 

[BIGV]

No the system is stock and I have done nothing new to the vehicle that would cause this. I only have 26,000 miles on the car so I can't believe the radio is shot. So since the car is awake for up to an hour after it is shut down I should wait before checking amp draw.

 

[BIGV]

Well I checked this morning still drawing .31 amps now I disconnected the gem module and it dropped to .16 then plugged the radio back in and it jumped up to 1.8. Could the Gem be bad and causing the radio to stay on.

 

[TVSCobra]

Sounds like to have something else that is waking the Radio up. You need to keep pulling fuses until this draw is under 50ma. I will look at the Ford manual for what is normal on these cars. Also what are you using to measure the draw?

 

[BIGV]

a volt meter it reads amps as well.

 

[BIGV]

I just read the manual and I have to make a jumper for the negative battery. I have been disconnecting then taking the amp reading. It says that I can wake up electronics doing it this way. I can't break the negative connection which is what I have been doing. So I may not have the amp draw I think I do. You were right it's 0.05 amps for our cars.

 

[Wayneo]

Yes, for a proper amp draw test you need to disconnet the negative terminal and jump a wire from the cable to the battery on the ground side and then install your meter leads. Open the d/s door to gain access to the fuses and leave it open while your testing. Let the vehicle sit this way for about a half hour to an hour then disconnect the jumper wire and leave your meter leads connected. This will give you the amp reading. If the reading is to high start by pulling the fuses that are not for the main modules since they pretty much power everthing in the car. Do not reinstall the fuses or open and shut the doors until you find the source of the draw or your modules will wake back up and you have to start over. Always diconnect your alternator to make sure that is not causing the draw since 9 out of 10 times the alternator is the problem. When you pull the fuse that drops the amps dramatically into spec you then have to go to everything that is powered by that fuse and disconnect each device until your amp reading is in spec and that should be the cause. That amps should be .025 to .031AMPS or .25 to .31 mamps.

Finding a draw can be a pain but this is a good way to find the source of the draw. It can also get more involved by having to pull individual wires out of the connecters to certain modules to isulate the problem more. Good Luck!!

 

[TVSCobra]

Yes, for a proper amp draw test you need to disconnet the negative terminal and jump a wire from the cable to the battery on the ground side and then install your meter leads. Open the d/s door to gain access to the fuses and leave it open while your testing. Let the vehicle sit this way for about a half hour to an hour then disconnect the jumper wire and leave your meter leads connected. This will give you the amp reading. If the reading is to high start by pulling the fuses that are not for the main modules since they pretty much power everthing in the car. Do not reinstall the fuses or open and shut the doors until you find the source of the draw or your modules will wake back up and you have to start over. Always diconnect your alternator to make sure that is not causing the draw since 9 out of 10 times the alternator is the problem. When you pull the fuse that drops the amps dramatically into spec you then have to go to everything that is powered by that fuse and disconnect each device until your amp reading is in spec and that should be the cause. That amps should be .025 to .031AMPS or .25 to .31 mamps.

Finding a draw can be a pain but this is a good way to find the source of the draw. It can also get more involved by having to pull individual wires out of the connecters to certain modules to isulate the problem more. Good Luck!!

This. ^^^^

Also latch the doors so the car "thinks" they are closed.

 

[BIGV]

Well the car has sat for 2 days and the battery is reading a steady 12.3 volts same as my truck. I believe the culprit is the radio and I am at a steady .31 amps not following the above instructions. I think once a do the test properly it will drop even more. We will see thanks for the help. One more question on my volt meter it has two option for volts and amps 20 and 200 I am guessing 200 is for amps and 20 is for milliamps or vice versa. All it does is move the decimal point.

 

[SVT_Troy]

'i know this is old but did you ever find out what was up with your radio? My radio is doing the same thing, if i disconnect it from the back of the radio the draw goes away.....