Dead battery, please help.

[1980corvettegibson]

I have a 1980 Corvette and a month ago i got some new speakers for my sound system put in. I used to have a 200 watt amp, and 2 10" subs, but they got stolen about 2 years ago. I put in a 900 watt amp and 2 12" subs. Ive drove the car about 4 times since i got them and the battery never went dead. Then all of a sudden i try to start my car and the battery is completely dead. The night before i had the hood open and the light was on, but it was flinkering alittle bit. I thought the battery might have been ran down by my door lock motor. the door locks dont work unless by key, and on the passenger side when i would lock it, it would make a noise like a motor..so i unpluged it. Then charged the battery up agin and 2 days after it started. then the third day it was dead agin. Not completely but it wouldnt run the starter. Im getting married in April and i want to drive my car on the honeymoon and im afraid to if i cant find out whats draining the battery. I took the battery off and to auto zone to have it checked and there isnt a dead cell. the machine showed it was just low. I also have an appointment this friday at the place that installed the speakers to have that checked. Also i took the speaker wires lose from the battery monday to see if the battery goes dead by thursday. That way if its dead then ill know its a short in the car and not speakers. but if it starts then ill know its the speakers and ill keep the appointment friday. Im kinda thinking that it wont start thursday though, so thats why im posting here, cause i dont know where to start looking for a short circit. I guess if nothing else, i could get a Priority Start from Eckler's (does anyone have one of these and if so, how good are they?) for $64.99. Its strange that ive had those speakers for almost a month and it never ran the battery down till now, unless its not them. Thanks for your time

[Yoda]

1980,
How versed are you in Electricity? The most common method I'm familar with would be to put a DC Amp Meter in series with the hot or ground lead of the battery, then record the current drain. Next would be to start pulling fuses and with each fuse pulled check and record the current drain. Eventually you will find the circuit causing the drain. (THE IGNITION SWITCH OFF)

That's just the start, next is to isolate the problematic circuit to find what component or connection is causing the drain and either replacing the defective component, or it could be as simple as making a new better connection.

Somethings I've seen cause problems are:

• Vanity Mirror light switch defective.
• Clock shorted.
• Bad brake light switch.
• Bad turn signal wiring.
• Glove box light switch.
• Interior auto light turn off module.
• Ect..

Electrical problems are some of the most challenging problems to locate, and usually easy to fix

Good Luck chasing these gremlins..

Bud

[1980corvettegibson]

I dont know much about electronics. My clock has never worked, and the vanity lights are unpluged. Im not sure if i should take it to the stero shop or a mechanic. I have a mechanic that would probly check it for free. A DC amp meter is one of those yellow boxes with 2 wires on it? If so, i have one of those and i can do that. So i put the negetive wire to the neg battery and positive to the possitive and see how much it regesters and pull out fuses and see if it changes? ALSO, what setting should i put it on? Thanks for the quick response. OH and im glad that the forums are back online. Those speakers sure shake the car, so it might have shook a wire loose. Ill know more Thursday when i try to start it. Thanks

[wishuwerehere82]

Watts = Volts X Amps.
900 Watts even at half volume draws a LOT of current if you are shaking the car.
12 Volts X 50 Amp alternator = 600 Watts. That's If the car is running. If not, then it will kill your battery in a matter of minutes. Most boomers have a couple of batteries for constant power. I would put a full charge on the battery and see if it will hold the charge. If not, it's time for a new one.

[Yoda]

I dont know much about electronics. My clock has never worked, and the vanity lights are unpluged. Im not sure if i should take it to the stero shop or a mechanic. I have a mechanic that would probly check it for free. A DC amp meter is one of those yellow boxes with 2 wires on it? If so, i have one of those and i can do that. So i put the negetive wire to the neg battery and positive to the possitive and see how much it regesters and pull out fuses and see if it changes? ALSO, what setting should i put it on? Thanks for the quick response. OH and im glad that the forums are back online. Those speakers sure shake the car, so it might have shook a wire loose. Ill know more Thursday when i try to start it. Thanks

Putting the test probes across the battery terminals won't give you the current drain, it will give you Voltage.

To series the DC AMP meter into the circuit you need to disconnect the battery terminal then MAKE sure the yellow box is capable of reading DC AMPS. Connect (depending upon which battery lead you disconnect, e.g. the Negative Lead) connect the POS lead of the DC AMP meter to the battery post and the NEG lead to the removed battery wire, putting the meter between the battery and ground. If you disconnect the POS battery lead, then place the NEG lead of the DC AMP meter to the removed battery wire and the NEG probe to the POS battery terminal .. THEN start pulling fuses

Bud

[1980corvettegibson]

Thanks, ill try that if the battery is dead tomorrow. The amp also has a remote bass boost control on it as well, sometimes when im driving around i would put it almost all the way up, but ive drove it like that a few times and it never ran the battery dead. Ill be honest, i have turned the key backwards a few times, but i knew not to leave it there along time. Our battery charger doesnt have a way of showing if the battery is full charged, so my dad said that we might not even got it fully charged anyways. Im real greatful for all the help.

[Bob Chadwick]

I was having a similiar situation with my car. I left the doors open for an extended length of time while I was putting in my steroe and started having battery problems. For the life of me I couldn't figure out why the battery was going dead. Came down in the middle of the night one time and found the interior lights on. They went out a short while later.

Turns out I fried the component that controls the light timing when I left the doors open for extended lengths of time. Age probably didn't help either. It would malfunction in the middle of the night and turn on the interior and exterior light under the car.

The component is between the speedo and tach under the dash on my car. I'll repair it next time I have the dash out. In the meantime, I pulled all the bulbs and haven't had the problem since.

[titan81]

Sounds to me like you have a broken circuit or faulty ground

Check you stero wiring for poor grounding,using a multi meter...
If not this then follow the ciruit to the head unit and see the number there..
Even if thou the battery pulls 12.6-13 v running it need more like 14 plus ALOT
of current to crank over...

Somewhere current is being lost/absorbed

[CQRT]

..."The night before i had the hood open and the light was on, but it was flinkering alittle bit. I thought the battery might have been ran down..."
I'd suggest removing the bulb or disconnecting the wire - -I'd guess that's where your grounding issue might be.

Regards-

[1980corvettegibson]

When my other speakers got stolen, they broke my head lamp , so now the only light i have inside is the drives side. I do sometimes have the doors open alot while working on things. I lately had it open taking the door panel off and takeing the door lock wires lose. Also i put on a new Steering wheel about 2 months ago. I might try to just take all the light bulbs out and see. OH today i tried to start it and it was dead. SO i cancelled my stero apointment for tomorrow. I guess im glad that it wasnt that. NOW i have my battery unpluged and ill check it agin Saturday or Sunday to see if the battery has a dead cell. The guy at Auto zone didnt know what to set the battery machine on cause the amp or something wasnt on the battery. So he put in 460. Ive had my car for 6 years and ive never had battery problems. It is a really old battery and its possible that the battery just died and has a dead cell. If so, thats easy to fix. I think the reason the hood light was flinckerin, was cause the battery was real low that night, cause the next morning it was completely dead, no fire to even run one light. But I aprisate all the advise and suport. Ill let ya know what happens Saturday or Sunday.

[wishuwerehere82]

Once it goes dead, the plates form lead sulate on them and it's downhill from there. Six years is a long time for a battery to last to begin with. Get a new one.

[1980corvettegibson]

yeah, its been a REALLY good battery. It ran my other sound system for 4 of those 6 years. Ill probly get a new battery, but i just wanted to make sure that something wasnt draining it, cause i wouldnt want to put a new battery on there and have it run down too Its real dark at our house at night , we live in the country and there is no night light on the light poles, and ive never seen any light on after the car is off. Is there any specific battery that i should get that would be good for a car with a sound system, or just any new battery? Thanks

[Mr. Chuck]

Have you had the alternator tested to insure it is still able to putting out it's full rated current? Low alternator output will cause the battery to not receive a full charge, also check the age of the battery; they will lose capacity as they age as the active plate material flakes off. I would inspect the eye on the battery to see if the green is bright (full charge) or a dull (less than full charge). Old or damage battery cables also reduces the battery's ability to receive a full charge. Any signs of corrosion, discoloration of the wire insulation may signify the need to replace the battery cable(s). Also insure that the frame connection of the negative battery cable is tight and clear of rust or other contamination.

[Mr. Chuck]

My Shop manual purchased when I got my 81(new in 1981) shows that both the clock and vanity mirror lamp has a common ground at the Instrument panel ground located on the left hinge pillar above the courtesy light. The same 20 amp CLK CTSY fuse powers the Glove box light, Clock, Cigar lighter, Dome light, Spare tire lamp, both Courtesy lights, as well as the vanity mirror lamp and interior light delay timer. if any of these lamps are working than the 20 amp fuse is good. If so, and the clock is correctly connected electrically, but still doesn't work; a tempoary ground wire connected from the clock connector ground pin to a point on the car frame will indicate a poor ground connection if the clock begins running. If the clock still doesn't run, a simple load test with a test light connected across the disconnected clock connector plug will verify a good fuse and related wiring circuit if the test light illuminates.

A basic load test light can be made by taking any 12 lamp (i.e. a #93) and two lengths (your choice, based on how far away a good frame ground is) of insulated wire (something like a 18 or 20 gage wire); strip about (1/4" - 1/2") and tin (apply solder coating with low heat (30 - 75 watts) soldering iron) to both ends of each wire (insure wire strands are neat and straight. Solder one end of one wire to the center contact on the lamp (insure that the stripped wire doesn't touch the metal base of the lamp), /take one end of the other wire and solder it to the metal lamp base at the point where the small solder spot is next to the lamp glass envelope. Low wattage soldering irons will insure that the lamp is not damage by applying to much heat to the lamp contact points. The two loose ends of the test light can be terminated in any way you like. One method is to solder an aligator clip to the wire connected to the lamp metal base for connecting it to ground (car frame), while the other wire would be use to touch (make contact) the source / circuit 12 volts DC power. The test lamp has the benefit of detecting faulty (high resistance) electrical circuit connections, where a volt meter would other wise display / imply a good electrical circuit exists. The base of the test lamp should be insulated with electrical tape of other means to prohibit it from shoorting out by touching the car frame or other electrical circuit component or contact point(s).

[garywcook]

Does the factory alarm still work? If it isn't working, then it can drain your battery. The relay will be activated but the horn won't blow because it's either bad or disconnected. Mine was "disconnected" because the bracket that holds it to the firewall was broken causing the horn to hang disconnected from it's ground.