Battery Drain May Be Due to Radio - help!

[bldn10]

'02 Tahoe that I have had for several mos. I am on my 2nd battery but it drains overnight. Seems to be charging OK and alternator checked out OK. I have a 2+ amp draw w/ nothing on that drops to .5 when I pull the 15A fuse under the hood for the radio, climate control, instrument panel. It drops to .02 when I pull the 25A radio amp fuse. Is there a separate power amp that could be staying on? I have the standard ST audio system. Is there some place I can start unplugging components one at a time? Seems like there are 4 or 5 fuses that involve the radio.

 

[OR VietVet]

Put all fuses back in and unplug the alternator and see what the reading is.

 

[SLCHOE]

'02 Tahoe that I have had for several mos. I am on my 2nd battery but it drains overnight. Seems to be charging OK and alternator checked out OK. I have a 2+ amp draw w/ nothing on that drops to .5 when I pull the 15A fuse under the hood for the radio, climate control, instrument panel. It drops to .02 when I pull the 25A radio amp fuse. Is there a separate power amp that could be staying on? I have the standard ST audio system. Is there some place I can start unplugging components one at a time? Seems like there are 4 or 5 fuses that involve the radio.

Are you doing that with the driver's door open? Open doors keep certain modules "awake" and draw current until the doors have been closed long enough and then they power down. Follow the procedure below (after 30 minutes with the door open you will be fine)

1. Select the highest amp scale on an ammeter and disconnect the battery negative cable.

2. Install the ammeter between the battery and the battery cable. A jumper wire needs to be connected in parallel to the ammeter to reconnect the battery at the same time the meter remains installed. Both the ammeter and a jumper wire are connecting the battery cable to the battery at this time. This allows the vehicle to power down (go to sleep).

3. Wait 30 minutes. Turn the ammeter on. Remove the jumper wire, being sure that the ammeter does not come disconnected. This is now the actual vehicle's battery drain.

4. If the draw is more than 50 mA (.050 Amps), remove the fuses one at a time to locate the source of the drain. Leave the fuses out until draw is isolated, as reinstalling may reset timers and give a false draw.

5. Consult a wire diagram to disconnect each component that is fed by the fuse causing the draw. If it is a computer causing the draw, check for signals into the computer that may be waking it up (handle switches, etc.).


NOTE: MAKE SURE ALL VISOR MIRRORS ARE SHUT AND ALL DOME LIGHTS, GLOVE BOX, ETC ARE SWITCHED OFF FIRST AS TO NOT WASTE YOUR TIME!

 

[bldn10]

Thanks for the responses. I had been over on the engine forum but it finally occurred to me that audio/alarm aficionados might know most about this kind of thing. Plus, it appeared that the radio might be implicated. Indeed, last night I pulled the 15A radio and 25 amp radio amp fuses and the battery had zero drain overnight.

I had never read about running the jumper but I did it that way. W/ everything shut down it read .87A. Taking the alternator out made no difference so that isn't it. I pulled the 25A radio amp fuse and it dropped to .39A, which I gather is acceptable.

So, audio gurus, what is it that is staying on and where can I unplug it? I don't see any evidence that this Tahoe has ever had any after-market alarm or power amp. I did replace the OEM speakers, that were all rotted out.

 

[bldn10]

No ideas on what audio component is causing the drain?

 

[jetcruzer]

it's probably your amp. I've replaced mine and problem started again after about 2 years. I put in a priority start that also lasted about a year. Now I just have a battery quick disconnect and no problem. It can also be automatic climate control if you have that.

Dealer wants 700 for a new amp. Pulled one from an Escapade for 200. lasted two years as I mentioned. Good luck, this is an ongoing and hard to find probelm.

 

[bldn10]

Turned out to be the starter. It finally got to where it would not crank even w/ booster in place so I replaced the starter. Did not experiences drain so put radio amp fuse back in - no problem.

 

[Johnb21]

anybody have any thoughts on the result being the starter?
Mine drain is from radio 15a - .5 amp and info/enter 10a - .25a, leaving me with .75-.8a leftover..

 

[about20ninj45]

Turned out to be the starter. It finally got to where it would not crank even w/ booster in place so I replaced the starter. Did not experiences drain so put radio amp fuse back in - no problem.

Eas ot hard to replace the starter? Where is it located at on our vehicle?

 

[bldn10]

Update - it was not the starter, continued to drain. I finally took it to a shop and they replaced the radio amp. Fixed. Had nothing to do w/ the starter or alternator.