1972 Dodge charger battery drain issue

[RobVoyles]

Hi, hope someone can help. My Charger is draining the battery with everything off.Brand new battery and alternator working perfect.
i did a test... and when you pull the fuse to the brake lights and hazards.. my led test light goes from
bright to very dim on my tester, im using a light between the neg post on battery and neg battery ground terminal to engine block.
it only shows a light... not a meter with amps or mili amps but im sure this circuit is the issue. The brake switch opens and closes
as it should according to my continuity tester and my hazards come on and off as they should. Also my misc fuse clip is broke
and fuse fell to pieces when i pulled it.Not sure what else may be on the brake hazard fuse circuit that may cause this.
Not even sure what the fuse to misc goes to. Any help would be greatly appreciated. Thanks in advance.
Rob

[70 sublime]

If you pull the brake light fuse and your test light that is between the - post on the battery and the cable goes from bright to dim still means something is drawing power
With nothing on the light should go completly out

Do you have a modern radio that has a wire to keep the memory alive ?

[b5blue]

Buy a meter for 6 bucks.

[Gold Rush]

Both previous posts have merit so I'm sure not disagreeing.

I expected by now someone would have asked if Rob had a service manual and maybe guided him to the wiring diagram.  I know several guys in the past have done similar things and even told the poster where to download the service manual.  Unfortunately I've never saved that information as I do have the shop manual on my '74 SE. Big differences between that vehicle and Rob's so I didn't even try myself.

Hopefully someone will jump and lend a hand.

MERRY CHRISTMAS EVERYONE!!

[Nacho-RT74]

I have had a similar issue, getting a dimming dome light and heating the fuse box fuse clip able to melt the fuse box. Same fuse. Believe it or not, I still haven’t found the problem. It was happening randomly.

I only can think on a tail lights bulb socket failure getting a small short, but haven’t had the time to check when it happens.

[b5blue]

https://www.bcae1.com/

[green69rt]

I'm going to throw out a possibility because it happened to me.

Check all the sockets for the tail lights.  I had the plastic insulator in a socket break and it shorted the power directly to ground.  Blew the fuse.  Yours may be similar but not enough to blow the fuse.  Good luck, electrical gremlins are a bitch!  You really need a clamp-on amp meter to check things out.

[Nacho-RT74]

[RobVoyles]

Thanks for reply guys, i have a meter( I couldn't find it so i just used the test light but i have it now...saved 6 bucks set to mili amps dc , it is pulling.003 after i found the parking brake light barely engaged.The bulb was dim but now off completely. I have no schematic but im assuming the parking brake light is on the same circuit as the brake lights and hazards. I will check the bulbs but a schematic would be helpful.The misc fuse is pulled but seems to go to nothing, because everything works, maybe it is there for options the car doesn't have, just a guess.I have the factory am Radio.

[b5blue]

With the key off disconnect positive at the battery and put the voltmeter leads in between. Look for a reading it should be 0.

[A383Wing]

parking brake light is on a 12v switched circuit, it should not be on the brake and hazard circuit...almost sounds like you have a switched ignition circuit shorted to a constant power source. Has anything been added to the car that is not factory equipped?

[Nacho-RT74]

Yeap, as mentioned the cluster brake light is on the RUN (ign1) circuit in fact. Hence why dims out while cranking, being retrofeeded from Ign2 through the ballast.

That’s a nice way to check you have ballast and Ignition circuits at bulkhead and ign switch in working order: brake light (and oil if standard cluster) keeps working and dims out.

[RobVoyles]

Thanks for the reply's and help guys, the car is completely factory with nothing added.I was told you could run your meter between the neg and wire or positive and wire and it would be the same, i have only did it thought the negative side but if it is a better test to run it through the positive side i will give that a try and see what it reads. My thought was it is in the ignition switch itself but with a reading of .003 in mili amps setting with a 50 year old car that may be acceptable and take a very long time to draw the battery down. i will continue to check the things you guys are giving me to try, i appreciate the help so much. Merry Xmas all and will keep you updated on any new developments.Thanks again! Rob

[b5blue]

So if you have a reading start removing fuse one at a time and checking for a change. (Again, leave the key off.) If all fuse are removed and you still have a reading let us know.

[RobVoyles]

ok, will do!

Thank you!