Battery drain

Old 12-18-03, 03:59 PM
Visiting Guest
Posts: n/a
Battery drain

I have a 1989 GMC Suburban which has a new battery. Lately, when it sits for several days, the battery is totally dead.
I've had the battery and alternator checked out and they are OK.
I disconnected the negative terminal and put a test light between the terminal and the cable. The light is bright. I removed fuses until the light went out. The fauly circuit powers the radio, cabin lights and horn relay according to the owner's manual.
I removed the radio and the light is significantly less bright, however, it still lights dimly. I have checked the vehicle in total darkness and no lights are on. The underhood lamp is switched and is not on. The horn works normally.
What am I missing here?
Any suggestions?
Old 12-19-03, 08:19 AM
comtnman's Avatar
Join Date: Nov 2002
Location: Colorado Springs,Colorado
Posts: 108
Received 0 Votes on 0 Posts

Do you have a volt meter? Usually they have a scale for reading AMPs, Try putting it in line like the test light and read the AMP draw. This may tell you more than a light that is bright or dim.
I'm not sure how much power the components draw that need to retain their memory, but I would reason that it is in the milli amps range. Maybe post this question in the Automotive forum the experts over there will give you an idea for the draw.
Old 12-20-03, 07:36 PM
billys68ss's Avatar
Join Date: May 2003
Location: USA
Posts: 1,459
Received 0 Votes on 0 Posts
You could have a faulty door lamp switch. Check to see if all of them make the light function. If one doesnt I bet that is your draw. Are all of the doors and hatch and such closed while you are testing for this draw? Also is there an underood light that lights when the hood is open? IF do this will cause a draw as you have to have the hood open to check.
Hope this is helpful to ya,
Old 12-23-03, 12:54 PM
Visiting Guest
Posts: n/a
Thanks for the hints. I have both analog and diigital VOM's and neither shows any current draw. The underhood lamp is switched so that's not it. I'll check the door switches and see what I come up with there.
Old 12-27-03, 01:01 PM
Visiting Guest
Posts: n/a
I had a problem very similar to yours with a ranger pick-up. I happened to look, just by accident in the ash tray for something. I used the ash tray for storage and loose change as I do not smoke. And took the lighter out so I would have power for a radar detecter. But I had the radar detecter in another vehicle. And at the bottom of the lighter receptacle was a single penny. Now I dont know for sure that was bridged across the positive and negative, but after recharging, and getting jumped off for a little over a week (plus a brand new battery, which I didn't need) after removing this coin, the problem went away. It may not be your problem, but it's worth a look. There might be something down in there. A little chewing gum and an icecream stick got it right out.
Old 12-27-03, 04:23 PM
Sharp Advice's Avatar
Admin Emeritus
Join Date: Feb 1998
Location: The Shake and Bake State USA
Posts: 10,398
Received 5 Votes on 4 Posts
Lightbulb My Two Cents

Hello: zekester

Based upon the info provided below:
The fauly circuit powers the radio, cabin lights and horn relay according to the owner's manual.
These may be powered by the ignition switch.

Some ignition switches are buildups of several switches. Which means the ignition switch has several parts all stacked up on top of one another to make a single switch.

The part which operates or allows current to go to the items you mentioned above could be defective, allowing current to flow to them when the switch is turned off. Possible & probable but rare.

On rare occasions, owner of RV's, Motorhomes, Boats, Campers, etc which have generators have like or similar problems. First thought owners & some vehicle electric mechanics assume, is the problem has to be the generator or it's electrical system.

Hours later of diagnostics testing, etc, finding out it was the vehicles ignition switch all along......

Regards & Good Luck. Sharp Advice.
Small Engine Forum Moderator.
Small Engine Diagnostics Services & Repair.
"Accurate Power Equipment Company." (We do generators too)
Fast...Fair...Friendly & Highly Proficient Services....
Old 01-03-04, 10:45 AM
Visiting Guest
Posts: n/a
Thanks for all the suggestions, guys. I finally found the culprit. It was an intermittent problem with the glove box switch. Sometimes it would close and the light stayed on. I checked in there about 10 times and the last time I found the lamp on. Replaced the switch and I'm good to go.
Old 01-03-04, 01:46 PM
comtnman's Avatar
Join Date: Nov 2002
Location: Colorado Springs,Colorado
Posts: 108
Received 0 Votes on 0 Posts
Thanks for posting the solution to the problem, you never know when it may help someone else.

Good job on getting that one fixed.

Thread Tools
Search this Thread
Ask a Question
Question Title: