Packard Forum Index » Pre-War (1899-1942)

I beleive its in my ignition wiring somewhere, any suggestions to fix?
thanks

Here is an old trick for tracking down current drains. Disconnect one battery cable and connect a test light in between the cable and post. If there is a current draw the light will light up. Now go to work and take out the fuses one at a time. When the light goes out you have at least narrowed it down to one circuit. Now you can check each thiing on that circuit one by one till you find the culprit.

When you do this be sure to shut off the dome light along with everything else.

Do you have a trunk light? If the mercury switch goes it can stay on all the time.Are there any other accessories not wired throught the ignition switch? Another place to look is the field coil of the voltage reg.

Other than that you have to take your test light or multi meter - voltmeter and check things one at a time. Fortunately 37 Packards do not have a lot of wiring or complicated electronic equipment.

Another hard one to find is the brake light switch. If it has developed a high resistance path, will be enough to pass a few mA of current and drain battery over a few days but not enough current to light the bulbs.

You haven't given us a lot to go on, but that doesn't sound right - ignition on should take several hours, 3 or more, to drain a battery "down". For example, with a fully charged battery you can usually drive 150 or 200 miles without a charging circuit.

I suspect what you have is a much more significant drain. Have you felt the generator? I think Rusty already suggested this but if your regulator cutout hasn't opened, the battery is trying to motorize the generator in which case it will be HOT; if this is the case loosen the fan belt and see if the generator turns like a motor. This type of drain can cause BIG damage to your generator so best check it out promptly. I'm not saying it's the problem, but you've apparently got a very large current drain and it's one of the few things I can think of that can draw off this much power.

PS - if you really think the discharge is in the ignition, it's very simple to check. With the key off, remove the coil-to-distributor low tension wire at the distributor and touch to ground - a spark means the ignition is "hot" when it shouldn't be - bad ignition switch the likely culprit but I think this is a pretty remote possibility.

Its not hot, could it still be regulator?

The possibility Rusty usggested is a grounded generator field connection. To check just remove the wire at the voltage regulator marked "F" or Field. Tape the end so it doesn't ground. See if the drain continues.

Though use of a voltmeter is nice, an easy way to see if you have a current drain with no tools is to, with EVERYTHING turned off, remove either batter cable and then, watching closely, bring it into contact with the battery terminal. Any spark indicates you have a current drain.

I presume you also recognize that a failing battery will refuse to hold a full charge - all the more reason to do the simple check above. If the test shows no spark or discharge at a battery cable and the battery continues to run down, the battery itself is suspect.

If you do see a spark, then the prior advice of inactivating one circuit at a time, either by pulling the fuse or disconnecting, until you no longer have a spark at the battery post will identify the problem exactly as suggested. No rocket science needed here - just a process of elimination.

If something is draining a battery that quickly, it must be pulling a huge amount of current. Even headlights will stay on for over an 1/2 hour with a good battery. Are you sure you don't have a bad battery with an internal short?

Use a multimeter on the amp setting and check it between the negative post and the negative cable on the battery to see that the draw load it.

Does your ammeter have anything to say?

Really fast drains are almost always the cutout on the regulator, but then you will see the discharge on the ammeter.

Remove the A (armature) wire at the generator. It should not be hot when the car is off.

Just for general reference, starting the car with the battery in backwards will often weld the points on the regulator. Been there.