Battery drain - SOLVED

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hotrod swinger

hotrod swinger

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1973 Swinger

I have a 250 mA draw that I’ve been trying to trace.

Not glove box, trunk light, interior lights, etc.

Checked brake light adjustment.

Disconnected alternator, not a failing diode.

Not the stereo.

The draw goes away when I disconnect the wires that connect to the neutral safety switch.
 
D2A62A0B-6C98-46C2-BC1F-3A39BAC6EAE3.jpeg
 
Well that is odd because that is all supposed to be powered through the ignition switch. Outer terminals are backup lights, center terminal is grounded in park/ neutral and is the neutral switch.

You might have something like a wet corroded harness "let's say" near the trunk, leaking juice between the dome light circuit which is hot, to the backup lamps line going on back to the rear. Just an example.

I guess? you have pulled all fuses and checked?

Also wondering if you inadvertently wiggled something when you disconnected the NSS and "disabled" the draw
 
I have been very careful not to inadvertently disconnect anything else.

I have pulled all fuses and checked.

I wonder if I have a short in my ignition switch? If I have a short in the ignition switch, disconnecting the neutral safety switch would eliminate that short, correct?
 
Just to be clear, I am not suggesting I will eliminate my NSS, that would be stupid. Just saying that without that ground connected a short in the ignition switch would go away.
 
To follow up, disconnecting the drivers side bulkhead connector also eliminates the draw.
6410051B-7A64-4AB6-B487-0192813AF35B.jpeg
 
That connector seems to consist of the wiper harness, the reverse lights, and the washer motor wire (which has been cut).
 
250ma is not a lot, like a 3w bulb.

Could it be a noise suppression capacitor attached to the wrong wire?

I'm leaning towards a weak short.

Have you looked at your dash guage lights in a pitch black garage?

Maybe your dash light dimmer is getting power from the headlight switch internally?

You could check current on the connectors of the bulkhead you pulled.
 
As Dana67dart suggested, I checked for current on the connectors. The turquoise wire has 250 mA current.
2A8F7F98-0CBA-47E8-B61D-916D60D9E188.jpeg
current
 
It certainly could be something in the ign switch "wandered around" internally
 
I don't have a wiring diagram handy, but if those two wires go to the nns the the next logical place to disconnect would be at the starter relay.
 
I just happen to have a 73 Dodge service manual here on my coffee table. If that wire is considered DBL (dark blue) as opposed to LBL (light blue), that color runs rampant through a splice to various things. Rear window heater switch, electric choke, ballast resistor, dash pcb and ignition switch for instance.

But because this problem seems to be hidden, how about the seat belt system? It seems to me that the seat belt interlock stuff started sbout that time. A lot of people were annoyed by the whole thing and it was common to bypass it. I see DBL wires going to a seat belt relay, warning lamp, buzzer, seat belt retractor switches. Maybe there's something there?
 
KosmicKuda said:
I just happen to have a 73 Dodge service manual here on my coffee table. If that wire is considered DBL (dark blue) as opposed to LBL (light blue), that color runs rampant through a splice to various things. Rear window heater switch, electric choke, ballast resistor, dash pcb and ignition switch for instance.

But because this problem seems to be hidden, how about the seat belt system? It seems to me that the seat belt interlock stuff started sbout that time. A lot of people were annoyed by the whole thing and it was common to bypass it. I see DBL wires going to a seat belt relay, warning lamp, buzzer, seat belt retractor switches. Maybe there's something there?
Click to expand...
Interlock was supposed to be in 74. But stuff like "key in" buzzer, light, etc are worrysome

OP if you don't have a service manual you can download it free from MyMopar. There are two volumes, one for body, one for chassis.
 
Asterisk indicates with tracer.
DBL*
Maybe Dana can figure something out with this. I'm mechanical, not a sparky.
20210507_125648.jpg
 
My simple way of diagnosing voltage draws like that with the key off.

First take the ground cable off then on back on again, watch for the spark. OK, you have a draw.

Then go into the fuse box first feel all of the fuses and see if one is warmer than the others, that would be the circuit with the draw in it.

Now back at the fuse box pull one fuse at a time, then check for spark at the ground cable again. One fuse at a time until you find the circuit where it quits sparking at the ground cable at battery.

That would be the circuit to look into further for the draw.

Remember electricity follows the path of least resistance to get back to ground. So it could be back feeding because of a corroded connection that it can't get through, looking to get out through the ground in the neutral safety switch possibly.

Have solved circuit draws like this and also dim lit park lights just on one side of the car because of a bad ground at the light socket base.
 
One of my last diagnostics was an after market Tach that was creating the draw. (would run the battery dead after sitting for a week). Disconnected the Tach and the draw went away.

Chinese made tach, imagine that . . .

☆☆☆
 
Update: I have disconnected the rear wiring harness and the seatbelt harness. I still have a 250 mA draw. Disconnecting the wiper and reverse light connector at the firewall eliminates the draw.
 
Headlight switch disconnected
Wiper switch disconnected
Seatbelts disconnected
Rear harness disconnected
Rear defrost disconnected
 
I am running out of ideas

Anything modified? Spliced in by previous owner? Radio "memory" circuit?

HERE TRY THIS Maybe you have a drain caused by corrosion/ wetness in the wiper motor park circuit

The wiper park circuit is "hot" whether key is on or off

To find out, connect all wiring/ fuses "as normal" Access wiper connector and probe (key off) to find hot wire. Pull that wire out of the connector and "safe" it off and reconnect wiper as normal except for park circuit hot feed. Recheck draw
 
Downloaded the wiring diagram from mymopar, and the blue wire with white tracer isn’t on the diagram
 
hotrod swinger said:
Downloaded the wiring diagram from mymopar, and the blue wire with white tracer isn’t on the diagram
Click to expand...

You don't want ONLY the two page diagram as those are simplifed and leave some things out. Get the full 73 service manual which is also there
 
He said there was a cut wire, wiper mtr? His wiper mtr is the one with the attached harness that plugs into the firewall.
 
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