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I am new to the forum. I have a 1965 corvette stingray convertible, purchased a couple of months ago.
I have been having battery problems, recently purchased a new battery but it will not hold a charge. My mechanic tells me something is draining the battery and we just have to figure it out by process of elimination.
He says I should disconnect the wiper motor first which he says is the most common cause.
We have ruled out the alternator and other causes for the engine to not turn over and start. I can jump the car and start it but this is obviously not a good long term solution.
I am currently trying to fully charge the battery with a battery charger I purchased yesterday to see how long it will fully hold a charge.
He sent me a picture of what the apparatus looks like but I have a rebuilt engine that is casting number 3970010, likely from an early 1970s chevy and I cannot locate the wiper motor to disconnect it.
The wiper motor doesn't have power when the ignition is off, so it's not likely. The most common causes on a C2 are glove box light staying on, clock stuck, courtesy lights staying on, diodes in alternator leaking current. You can eliminate all of these fairly easily without replacing parts. The quickest way is to put an ammeter in series between one of the posts on the battery to the cable (disconnected) that goes on that post. With the ignition off, you should draw less than 50 ma or so (.05 amps). If it's more, I'd go in this order:
Check glove box and courtesy lights to see if they stay on with doors shut
Make sure brake lights aren't staying on
Disconnect red wire to alternator and see if current drops to a low number
Pull fuse to clock (bottom fuse, marked "stop/ctsy")
With ignition off, that's the most likely suspects. The next most likely is a weak "new" battery. The ammeter will tell you if you're drawing too much current with car inactive.
Welcome to the forum. I would start by determining if the battery will hold a charge. The alt. could be charging, but a bad diode will discharge a battery in a few days. Lastly, you do not need to disconnect the wipers or any other accessory, just disconnect the fuse on the line supplying power to the circuit. It could also be poor or a dirty connection in the charging system.. Do a search of the forum and you will find that many have written about your problem. Good luck. Jerry
The wiper motor doesn't have power when the ignition is off, so it's not likely. The most common causes on a C2 are glove box light staying on, clock stuck, courtesy lights staying on, diodes in alternator leaking current. You can eliminate all of these fairly easily without replacing parts. The quickest way is to put an ammeter in series between one of the posts on the battery to the cable (disconnected) that goes on that post. With the ignition off, you should draw less than 50 ma or so (.05 amps). If it's more, I'd go in this order:
Check glove box and courtesy lights to see if they stay on with doors shut
Make sure brake lights aren't staying on
Disconnect red wire to alternator and see if current drops to a low number
Pull fuse to clock (bottom fuse, marked "stop/ctsy")
With ignition off, that's the most likely suspects. The next most likely is a weak "new" battery. The ammeter will tell you if you're drawing too much current with car inactive.
X2 with these suggestions. 65GGvert is prettty much the guru when it comes to tracking down electrical issues with these early 'vettes
P.S. I would be looking for another "mechanic".
Had the same problem with my 63. Tracked it down to glove box light. I adjusted the glove box door/latch to shut tight and turn off the light.
Good advice from first reply.
X2 with these suggestions. 65GGvert is prettty much the guru when it comes to tracking down electrical issues with these early 'vettes P.S. I would be looking for another "mechanic".
Had the same problem with my 63. Tracked it down to glove box light. I adjusted the glove box door/latch to shut tight and turn off the light.
Good advice from first reply.
This reminds me of the thread the other day about checking to see if your glove box light was going off by triggering the video function on your smart phone and putting it in the glove box . Shut the door, open and see what kinda video you got. Though it was pretty neat.
Thanks for the help. My ammeter "died" today and when I went to my local auto store they did not have a simple replacement. I will need to find one on line and order it.
In the meantime, I was able to charge my battery and get my vette started. I have ruled out several of the potential problems mentioned in the responses. When AAA came out and jumped me a few weeks ago the ran the testing on my alternator and everything looked normal. I am thinking that the problem is the clock; it does seem to "get stuck" randomly although it does work most of the time. I need to remove the fuse and see if that takes care of my problem.
I am sorry if this is a stupid question, this is my first classic car and I am still "green". I found the fuse box on the drivers side but there is no fuse labeled "stop/ctsy" for the clock there. Is there a second fuse box?
This reminds me of the thread the other day about checking to see if your glove box light was going off by triggering the video function on your smart phone and putting it in the glove box . Shut the door, open and see what kinda video you got. Though it was pretty neat.
You need to get and install a battery disconnect for your car. They are available and not expensive. That way when you leave the car overnight, the battery is not being drained. Most folks prefer the knife-blade design, but a "green ****" disconnect made in the USA should also work fine. This is the one that I have on my own car.
You also need to get and hookup a multimeter that reads AMPS to your battery. That way you know how much current is flowing during your testing. When it drops to zero, you know you found the problem. If you don't have or can't get a good multimeter (like Fluke) for troubleshooting, you can also make and use a 12 volt bulb with about 6 inch twin leads with alligator clips. If you go this way, let me know and I can guide you thru its use.
Thanks for the help. My ammeter "died" today and when I went to my local auto store they did not have a simple replacement. I will need to find one on line and order it.
In the meantime, I was able to charge my battery and get my vette started. I have ruled out several of the potential problems mentioned in the responses. When AAA came out and jumped me a few weeks ago the ran the testing on my alternator and everything looked normal. I am thinking that the problem is the clock; it does seem to "get stuck" randomly although it does work most of the time. I need to remove the fuse and see if that takes care of my problem.
I am sorry if this is a stupid question, this is my first classic car and I am still "green". I found the fuse box on the drivers side but there is no fuse labeled "stop/ctsy" for the clock there. Is there a second fuse box?
GSK
Only ONE fuse box on these old cars. Your owners manual should show the clock fuse.
sounds like you have not yet added a battery cut off switch to your Grd post of battery.
this is one of the smartest things to add to your 65, will keep your battery healthy and your car safe while you track down what is running it down. Your clock will always be wrong, but you don't care what time it is anyway when driving your new classic corvette.
(sorry Larry)
Did not even think of looking in the old owners manual; I actually have the original from 1965; bought a cheap copy so I could protect the original.
Anyway, the fuse for the clock is not an individual fuse at the bottom of the fuse box in my 65 in the event someone else is having the same problem and reading this post.
It is included in the fuse for the instrument, radio and clock lights 3AG/AGC 4 amp fuse. This is the 4rth fuse labeled panel LPS.
I am not really sure I want to take the fuse out and have several dash instruments that are currently working shut down.
My plan is to keep using the battery charger/maintainer for now. It is keeping the battery charged. I will get a new AMP meter and follow the threads recommendations to more fully determine the problem.
I will definitely purchase a battery disconnect; would have never thought of that!
I will definitely find a new mechanic until I learn enough to do more of the work myself!
Installation of a new battery gauge is not trivial- requires pulling the instrument cluster. Also, getting one locally is not likely.
Get a service manual and assembly guide. Do a lot of searches here.
Installation of a new battery gauge is not trivial- requires pulling the instrument cluster. Also, getting one locally is not likely.
Get a service manual and assembly guide. Do a lot of searches here.
I don't think he needs a new dash gage.................he needs an AMP meter function on a good multimeter like Fluke to troubleshoot his problem. You connect the meter leads between the battery + post and the battery + cable and read the amps being drawn by the electrical system.
The last time I check, I believe that stuck contacts in the clock will draw about 4 amps load. At least that is what I remember. It was MORE than my Battery Tender was capable of putting out.
Thanks for the help. My ammeter "died" today and when I went to my local auto store they did not have a simple replacement. I will need to find one on line and order it.
In the meantime, I was able to charge my battery and get my vette started. I have ruled out several of the potential problems mentioned in the responses. When AAA came out and jumped me a few weeks ago the ran the testing on my alternator and everything looked normal. I am thinking that the problem is the clock; it does seem to "get stuck" randomly although it does work most of the time. I need to remove the fuse and see if that takes care of my problem.
I am sorry if this is a stupid question, this is my first classic car and I am still "green". I found the fuse box on the drivers side but there is no fuse labeled "stop/ctsy" for the clock there. Is there a second fuse box?
GSK
It's the bottom fuse. You can see "stop" in the lower right corner. The 65 clock gets it voltage from the "stop" fuse, not the "instr". With that fuse out, you'll also lose courtesy lights, glove box light and clock.
Don't rule out the alternator yet. Wait until you get your ammeter (external multimeter, not in dash ammeter for those reading that into it), and if you have too much draw, disconnect the red wire to the alternator and see what happens. Checking the charge can show good and still have a backward short (very small drain is possible) in the diodes. Get that meter and start with measuring amount of drain. Post back what you get if you like and I will try to help you through the steps if you want me to.
It's the bottom fuse. You can see "stop" in the lower right corner. The 65 clock gets it voltage from the "stop" fuse, not the "instr". With that fuse out, you'll also lose courtesy lights, glove box light and clock.
OK thanks; would not have known that reading thought the owners manual, thats for sure!
06-18-2016, 10:00 AM
Battery drain
