C3 battery drain

[Jim M.]

My battery is draining over night so I've got something that's not right. My question is the best location for my amp guage to check how much draw I have when everything is supposedly turned off while disconnecting circuits at the fuse panel?

[Terry M.]

Re: C3 battery drain

At the positive battery cable. Since the amp meter has to be in series with the battery cable, it should be easy (well, almost) to remove a fuse and look back to the battery compartment to see the meter.

Edit add: Just a hunch. disconnect the red lead from the rear of the alternator as your first step. Be sure to insulate it when you remove it so it doesn't accidentally contact ground when the battery is re-connected.

[Isaac G.]

Re: C3 battery drain

My battery is draining over night so I've got something that's not right. My question is the best location for my amp guage to check how much draw I have when everything is supposedly turned off while disconnecting circuits at the fuse panel?

Hi Jim, I have the same problem with my recent 82 purchase? can you fill me in on how you resolved the problem. Im thinking of removing the alt. to have it checked out at the local parts shop, but im not sure if this is the right way to go. Its the original and maybe its time for a replacement. Anyway if you can chime in please do, Thanks for your time.

[Edward J.]

Re: C3 battery drain

Jim, the most common circut with electrical draws is the dome lamp circut, it seems to have the most componets tied in with the circut with the key in off postion, I.E. clock, dome lamps, cigar lighter,rear compartment lamp,horn?

[Jack H.]

Re: C3 battery drain

Hum, don't forget the 'hidden' loads like the glove box lamp. Does it really turn OFF when you shut the door?

Electromechanical clocks can be another in-obvious load. A set of points close roughly every 90 seconds to fire the winding solenoid and re-cock the clocks' mainspring. BUT, if the points 'weld' shut, the clock can be drawing healthy current all the time.

Bottom line, you fix these kinds of problems by (1) finding the source(s) of electrical drain, and (2) fixing them.

Advice: if you aren't electrically skilled, consider driving 'baby' to a competent auto electric shop. They generally find/pin-point these kinds of problems in one hour or less...

[Kenneth T.]

Re: C3 battery drain

Jim,

Is this something new? If so what have you done to the car lately?

If you have had the starter out, it is a common problem for the ground wire to be placed on the solenoid which will draw power, it is the one that provides ground for the wipers. Same goes for the alarm system, any changes?

If you have not changed anything and this just began then it just may be the usual suspects.... alternator, batt cutoff switch, glove box light

Ken

[Roger O.]

Re: C3 battery drain

My battery is draining over night so I've got something that's not right. My question is the best location for my amp guage to check how much draw I have when everything is supposedly turned off while disconnecting circuits at the fuse panel?

Jim,
I disconnect the neg cable and put a 12v test light between the neg battery term and the neg cable , you can do the same thing with your amp meter but be sure your in the high amp scale of your meter or you'll pop the fuse in your meter or ruin the meter. You need 10 amps , some meters require you pull the probe and move it in the front of the meter to 10 amp.
From there you just start pulling fuses until the meter drops or the test light goes out , that will be the circuit with the draw.
Roger

[Jim M.]

Re: C3 battery drain

Issac, I finally found my battery drain problem but took me a little while to discover the culprit. There is a ground that attaches to the top starter mounting bolt or at least there is on a 69. This is the ground for the heater fan (located just above the starter, plus a ground for a couple other things if I remember right. Turns out that the previous owner had attached that ground to the hot side of the starter instead of the mounting bolt. So, in my case, I was grounding out the battery through that heater fan. Once I moved that wire off the starter hot side. the problem went away. Hope this helps. Jim

[Isaac G.]

Re: C3 battery drain

Good morning Jim,
I am going to check this area out. When I first brought the car home it was in storage for a bit and it ran with a rough idle, so i started tinkering with a tune up, new sending unit, filters, belts, stuff that my limited abilities could tackle and maybe i didnt reconnect something right. When I lowered the gas tank i noticed two wires that feed the spare tire light with no light socket attached, i fixed it and my next issue is with the horn that doesnt work. I have looked high and low for it but no horn, once i find it i will try the fix. I will also retrace my handy work and see if something gives. Thanks for the help im encourage by your tip.

[Jack H.]

Re: C3 battery drain

But, there are electrical branch circuits that are NOT fused. So, you can remove ALL of the fuses and not discover the faulty branch...

Bottom line, this approach is a necessary but NOT a sufficient test.

[Jim W.]

Re: C3 battery drain

Jim,
I disconnect the neg cable and put a 12v test light between the neg battery term and the neg cable , you can do the same thing with your amp meter but be sure your in the high amp scale of your meter or you'll pop the fuse in your meter or ruin the meter. You need 10 amps , some meters require you pull the probe and move it in the front of the meter to 10 amp.
From there you just start pulling fuses until the meter drops or the test light goes out , that will be the circuit with the draw.
Roger

Jim, this was a problem with my 79 for the first year. I found it one night as the parked the car into the garage and was pulling down the door after the timed delay had already gone out and I noticed a slight glow from the drivers side of the car, It was the underhood light staying on.

If you go with the above advice, I'd do it at night in a pitch black garage and just touch the negitive terminal to the post and see if you hear and 'clicks' or see any lights go on or off. Good luck !