Battery Drain Kicking My Butt

countrysquire

countrysquire

Senior Member
I have something that is running down the battery in my '40 Tudor but cannot seem to find it, despite having a wiring diagram and very few circuits to check.

With my Fluke meter between the positive post and the ground strap, I'm seeing 0.58 and 0.60 amps. Disconnecting at the solenoid connection from the battery drops it to zero, as does disconnecting at the circuit breaker under the dash. Nothing else I've disconnected has made any difference. These include:

Voltage regulator
Horn relay
Ignition switch
Cigar lighter
Coil
Switched side of solenoid

What am I missing?


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Did you disconnect at the LOAD side of the circuit breaker? I've never seen it, but possible the circuit breaker has a partial short. If there are multiple wires on the load side of the circuit breaker, disconnect them one at at time.

You didn't mention disconnecting the light switch.
 
The radio is in place, but not connected. I disconnected both sides of the circuit breaker with both removing the draw. I have not messed with the light switch yet because I will have to remove the radio to get to it. It looks like the one wire at a time method will be next.

Thanks for the quick suggestions, I'm gonna keep at it.


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I guess this is one of the reasons to install a battery cutoff switch. I have not dome so in my 1933, but with these cars you can have something happening electrically. I replaced my harnesses because of the decaying condition of my harnesses.
 
The wires on the light switch are very close to the metal at the bottom of the dash, look at the hot wire's insulation here. Also, have you left everything in place and disconnected the BAT term on the voltage regulator and checked?
 
Yes, my initial guess was the voltage regulator, but that was not it. Disconnecting the side of the breaker that feeds the light switch removes the draw, so it looks like I'm closing in on the light switch.


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countrysquire said:
Yes, my initial guess was the voltage regulator, but that was not it. Disconnecting the side of the breaker that feeds the light switch removes the draw, so it looks like I'm closing in on the light switch.


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Click to expand...

Oh the Infernal Light switch...
On my 33 the switch actually came apart.
 
This one has some goo leaking out of it, which is probably not a good sign. Now to figure out how to remove the damn knob to get the switch out...


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Awesome, I searched but didn't see that thread. I was puzzled when I didn't find a button like on later Ford switches.


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Looks like I celebrated too soon. With the headlight switch removed and disconnected, I still am drawing 0.57 amps as measured from the breaker to the wires that connect to the other side of the breaker (removed from breaker). I've disconnected the pillar light wire, thehigh beam indicator, cigar lighter, high beam switch, and brake light switch with no change. It looks like the harness was replaced when the car was restored in the '80s, but the colors have faded, making wire identification a little tougher.

I suppose that it could be a short somewhere within the braid covered bundle, but I've moved them around quite a bit with absolutely no change in the amperage reading. There are four wires joined together that are fed from the circuit breaker. I'm just about to the point of cutting each of those wires individually to see if I can isolate the trouble maker. This is why I drink...


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No heater, but I do have it isolated to one wire now, going to the brakes and was back feeding to the headlight switch, sending me down the wrong path.


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Part of the problem is how you are going about this. Just jumping from one thing to the next is confusion and doesn't get you where you want to go in a systematic faction. You have listed disconnecting a some things that would be very, very unlikely to be the source of your problem. Need to start at the load side of the CB and work from there.

What year are we dealing with here, 40? Remove everything from the load side of the CB, should be only two wires, Yellow/Red to the Lighting Switch & Black/Blue to the Pillar Light Switch. If the current draw goes away it is one of these two circuits, if it is still there you can eliminate everything from the load side of the CB, no need to check anything else.

Assuming the current draw is still present, remove all of the wires from the Batt side of the CB. Connect them back one at a time starting with the Yellow wire from the Starter Relay and check for the current loss as each wire is attached.

Next attach the Yellow/Green wire to the Cigar Lighter.

Then the Yellow/Black to the Ignition Switch.

Then the Yellow/Black to the Voltage Regulator.

One of these checks has to locate the problem.
 
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That actually pretty much the method that I have gone through, but it was easier to list what has been disconnected as opposed to going through a lengthy dissertation of the entire process.

After narrowing it down to the brake light wire, it went away after the wires at the rear were reversed.


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countrysquire said:
That actually pretty much the method that I have gone through, but it was easier to list what has been disconnected as opposed to going through a lengthy dissertation of the entire process.

After narrowing it down to the brake light wire, it went away after the wires at the rear were reversed.


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LOL, Don't you just love it!:)
 
Ok, all back together and it was simply swapped wires going to the tail lights. Oh well, I learned about the wiring on the car, plus it gave me an opportunity to clean all the connections...

Thanks for everyone's help.

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