I've got a brand new battery in my 81 but something keeps draining the power. I figured that it was the old alternator. I kept it disconnected for 3 days and it didnt drain. I went and bought a new alternator last night and hooked it up. I came out this morning and the draining started again? Any ideas on what could be causing this? I need help really bad. :cry

 

i'd start at the ign. switch. remove neg. cable from batt. and connect test
light between cable and post. if it is on power is going somewere,start chasin
it by circuts, then isolate problem in the circut... P.S. i have had a starter
solinoid drain a batt. down in 8 hrs. but it still worked :eek: :eek: good hunting :thumbs:

 

Welcome to the club! More then likely you have a short somewhere.
Could be just about anything, power anttena, anti-theft relay, grounded positive battery cable, etc.....I am having the same problem and I'm not any
good at troubleshooting these kinds of problems. So I went out and bought
the Priority Start module and put it on the battery. Now when the module
detects a slow battery drain it disconnects the battery so you will never completly drain the battery and will have power to start. It is only
work around for now until I can find the short circuit. But at least my
battery will stop being drained as this really ruins the battery's life.
I'd tell you to search the archives but that feature is currently broken.
Good Luck :seeya

 

9 times out of 10 its the interior delay box. Disconnect the fuse that feeds your interior lights, I bet your drain goes away. :thumbs:

 

I don't have any real electrical diagnostic tools. My basis for tellin that the battery drains are the dimming of the lights when i open the door. If i took out the fuse how could i tell about the battery? Where is the interior delay box and where can i find a replacement?

 

I'm gonna say that LAvetteman probably has the first thing to check. Sometimes it's also water in a lamp...like a tail lamp or license plate lamp.

In order to check something like a slow drain the best tool is an ammeter. You can get one at an electronics store like Fry's electronics...you can order from their warehouse at [utl]http://www.outpost.com[/url]. A cheap $39 Volt Ohm Meter (VOM) from B&K would work fine for you...make sure it has a 10A setting. You use a VOM by setting it up for current readings of 10A then disconnect the positive battery cable, connect the black lead from VOM to the cable, and connect teh red lead from VOM to the positive battery terminal. It will read that current. Very important that you don't try to start the car, or turn on your headlights while the VOM is connected or you will fry your VOM...it will start smoking (and we all know that smoking is bad for you) because over 10A will be flowing through the meter. There may be a fuse in the meter...but if it blows they you will need to take the meter apart to get at the internal fuse...etc. Anyway...after connecting the VOM as indicated then you will be able to read the current being drawn. If your car has a clock then there could be around 100 milliamps (1milliamp = one thousanth of an amp), and a stereo system sometimes keeps an LED lit which could be another 100milliamps, plus a disarmed alarm system could actually draw between 50 and 250 milliamps depending on how it's set up. All together a draw of less than 500 milliamps can be ignored for a drain that will suck a new battery dry overnight. You will be looking for a drain of at least 2A and maybe more like 5A. You will find out what is causing it by removing fuses until the VOM reading drops to a low level. Then it's a matter of inspecting the device(s) which are running on that circuit and fix or replace them.

I hope this helps...I know how frustrating tracing shorts can be. I once spent like 10 hours on a short spread out over two weeks and I think I traced every wire in the vehicle until I found water in the license plate lamp...the clue was getting pulled over by a cop for not having a license plate lamp!

 

I'm having the same issue (big surprise) but I'll check out the interior delay box. Is it safe to pull that fuse and leave it out or no?

:cheers:

 

I have the same problem, will try the suggestions posted here and will post my results, thanks.

 

Had a drain in my 81.
Turned out to be the light switch in the vanity mirror, located above the passenger visor.......

 

:eek: think you was gettin' pretty to often :lolg: :lolg: :lolg:

 

I'm starting to believe that all Corvette have a power drain. My '79 does, and more often than not it seems that every Vette owner I mention it to claim to have the same problem. C5s included.

My advice, purchase on of those battery disconnect switches that attaches to the end of the battery cable and clamps onto the battery post. About $12. and your problem is bypassed.

 

Mine was drainin from the storage light behind the seats. Hookin a test light up between the disconnected - battery cable and - battery terminal will light the test light if u have a drain. The test light will go out when u pull the fuse for the bad circuit. Make sure your dome light is not on or other accessories. I just tape the switch at the door.


[Modified by Tom Johnson, 11:51 AM 1/26/2004]