1973 cadillac eldoradeo ,battery drain when the egnition is off??

[34858]

Hi have a 1973 eldoradeo when you turn the egnition off the battery drains.
any one had this problem??thanks Kenny

[Series75]

Sure did.  Weeks of searching.  Pulling fuses, etc.  It was a significant drain as overnight it pulled the battery right down.  Turns out it was the passenger power seat.  The center round adjuster would stick in the FORWARD position. 

[V63]

An alternator/regulator  defect can cause this as well. Aftermarket audio,  if applies.

[bcroe]

A couple of mine included a trunk light that never
turned off, and a brake light switch adjusted so
that sometimes it did not turn off.  Bruce Roe

[TJ Hopland]

To narrow down what's causing the drain you need a way to measure the draw.  A multimeter with an amp function (usually 10a limit) can work but you have to be careful not to overload it.  You can also rig up a lightbulb to 'read' the draw.

Either way what you want to do is disconnect the neg at the battery then hook your properly configured meter or light bulb inline / inbetween the battery and battery cable so the power has to run through your meter or light.  Its probably best to jam something in the door switch to keep the interior lights off with the door open and still give you access to the fuse box.  Interior lights plus a buzzer and a few other things could add up to 10 amps so be careful.  Since this is a coupe there is also the second door jam switch for the seat back release you will also have to jam up so you have the door open.

If you are going the bulb route and expecting a high load start with a large bulb like a headlamp.  These have to be old school bulbs, LEDs won't work.  As you get things narrowed down or know the load you are dealing with you can move to smaller lamps like maybe a tail lamp that will be easier to see the slight glow for a small load. 

Pretty simple the higher the load the brighter the bulb will light.  If you do something like hit the starter bulb just burns out so not the end of the world.  You can use things like jumper cables to extend the bulb to somewhere you can see it.  Since you are working on the ground side if something 'shorts' you will just be grounding it anyway and messing up your test no boom boom.

You should see either an amp reading on your meter or the test bulb glowing.  Start pulling out fuses.  When the light goes out or gets dimmer you found a fuse that has a draw on it. Next step is look in the manual and see what's on that fuse so you know where to be looking. People have had some good guesses, I will add one more.  Does the horn work?  I have had cars where something in the steering wheel failed and stuck the horn on so they unplugged them or cut the wires somewhere which does stop the horns blowing but leaves the relay on which is enough to eventually kill a battery.   

[The Tassie Devil(le)]

Don't forget that your Clock is constantly drawing power, as is any aftermarket radio that uses power to keep the stations.   Doesn't draw much, but any draw can lead to low power.

Bruce.