Hey everyone. I found a drain in my '70 Mav's battery a couple weeks ago that, long story short, I have been able to trace (at least partly) to the courtesy light in the cabin. I found it when I noticed a huge drain when I'd open the door (activating the light), already having known there was a drain when I'd turn the key to ON (but not Start). So I took the light out to see if it would mitigate that portion of the issue, et voila, that drain is gone. However, the drain from the key ignition still persists. The car's the very base-line 1970 model, so according to the fuse/circuit specs for it, there isn't really... anything else on the circuit? I read about a door buzzer, but couldn't find it behind the dash, have never heard one in this car, and am not really even sure the '70s were equipped with them, haha. It's really bugging me as this is my daily driver and it gets pretty tiring asking for a ride to and from work every day! Two notes- I replaced the bat/alt/volt reg as "moved to the mountains from Atlanta" heading in to winter's cold-weather precaution; and my passenger side door's light activating button hasn't worked since I've owned it. Or at least not for a long time. Perhaps that might be creating the draw? EDIT: Apologies because I suppose I have one more thing to mention (adding to original post as well)- the car was starting more and more slowly to the build up to the point that it just wouldn't start without a jump and now even with a jump it won't start - which was the original impetus for replacing the charging/bat system anyway. Thanks a bunch in advance!
How much current is it drawing??? If I understand it's now only with ign on?? How about accessory?? Assuming you have a points dist, if points are closed and ign on, there will be a couple amps draw... Plus any warning lights...
I actually have replaced the points with electronic ignition (Ignitors). Sorry, maybe I should have mentioned that It pulls down to 3.5v immediately and keeps dropping heavily from there. Accessories- dash lights et al- pretty much follow the same.
Apologies because I suppose I have one more thing to mention (adding to original post as well)- the car was starting more and more slowly to the build up to the point that it just wouldn't start without a jump and now even with a jump it won't start - which was the original impetus for replacing the charging/bat system anyway.
It started spinning slowly and would ignite at first, then eventually it would spin slowly and then stop. It still does the former if I'm getting a jump.
I checked down the line for where the drain could be coming from, and it was coming before the starter for sure- I suspect the starter cranking slowly had more to do with the voltage drop with the key on than anything... Once I get this sorted out, I'll get AutoZone to test the battery. It is brand new, but I worry the constant testing and draining might get to it. So I found that there was a pretty badly burned/corroded ring connector on the BAT terminal of the alternator (from the old alt that I replaced... "small" oversight on my part), so I cut down the bad copper and soldered a new ring terminal to the good wire. No word yet on whether or not it did the trick as I managed to crack my starter solenoid in half while tightening the wires back to the posts.
Good work, no doubt needed repair to keep battery charged, still if engine doesn't spin over on jumper cables there is likely battery cable or starter issues... A dragging starter will overheat the solenoid, causing weakening and/or cracks in the bakelite housing, at that point doesn't take much stress to break it open...
I hear that. Once I get the new solenoid on, I'll get a jump and measure what's coming through the system with the key on. If it's 12.5 or up, I'll know it's the starter crapping out on me - but if it's not enough juice to crank then it'd still be some parasitic draw? Am I thinking about that correctly? And as a side note- with a draw coming from the alternator's power terminal (due to the crappy wire) it makes sense that the car starts losing juice any time the battery is activated- ignition, light on in the cabin, etc? I guess that should be more of a question of whether or not power is sent to the alternator when anything uses the battery without the car running?
The alternator does nothing until engine is running, up to that point it's just a ornament... The bad wire would only limit the alts charging ability, not draw additional current... With ign on & engine off there will be some current draw from alt field, the warning lights and whatever may be turned on, fully charged battery voltage should be around 12.2-12.4v.. Once engine is running and alt is charging, voltage at battery should be at least 13.8v and 14.4 is perfect...
Alright- so I got the solenoid replaced, still a draw with key on/any power being delivered to the cabin... I'd have no qualms pulling all the fuses if I already hadn't strained my neck pulling just one this weekend, haha. Fun fact: my wipers went out and then came back about a month before/subsequent with this happening. They went out for good a couple days before the car couldn't even get jumped Not sure if that's any kind of help but, there that is.
A all but discharged battery will mimic a heavy current draw, what happens when you turn on just the head lamps???
Huh, I hadn't thought to try that... I tried it- same thing as the accessories but more extreme! Drops below a volt when I do that!
