Starter Problem and Parasitic drain?

[AnnieOakley]

So, I start with a full battery (confirmed) but my car doesn't turn over, then after an hour or so of troubleshooting (with the key out) my battery has magically been drained.

Is it possible that I have a problem with the starter that is also acting as a parasitic drain? If so - how do I find it?

 

[Torxhead]

The starter cannot act as a parasitic drain as there should be no juice going to it until the starter solenoid is turned on. You should try removing one of the terminals to the battery to retouch it briefly and look for any sparking that would indicate any drain providing you have no obvious drain on like a clock or radio. You can also check for drain by hooking up a milliamp meter between a battery post and a terminal. If you do get any sort of drain, which can sometimes be caused by bad insulation, you can just start disconnecting stuff until it stops. Having a multimeter can really help here.

 

[SlowPocono]

What do you mean by "turn over"?

How did you confirm that your battery was "full"?

It's not unusual for a new battery to be defective.
For a fully charged battery to be flat after an hour without some large drain is unlikely.

 

[AnnieOakley]

I'm pretty sure something in the ignition is staying on because when we tried to jump it a second time, the car attempted to start itself for about a second as soon as the cables were attached - even though the key was out - we also smoked/melted the cables, not sure if that has to do with anything.

Also - no clock or radio in mine - the only things that should be able to drain battery without the key in are the headlights and the fuel pump - neither of which were on.

I did buy a multimeter so I could test the battery and confirm that it was actually charging but unfortunately my electrical knowledge is minimal so I'm not exactly sure how to use it to check for a drain.

What I mean by "turn over" is that a key turn literally does nothing... No groan, no click, nada.

 

[Torxhead]

Yikes! that's not good. My first guess would be to check the starter relay. As there might be a short in that. With what has happened, you might have also fried the fusible links which are also connected at the battery side of the relay that are on the wires connected to the ignition switch and the alternator. My suggestion would be to contact the pros or do a lot of research on your starter system and how it works. That multimeter could help you trace it down though.

 

[AnnieOakley]

Just to close the loop - I changed out the starter solenoid switch and that did the trick! Thanks for all the help!

 

[Hedgehog]

I'm an old fashioned "If it walks like a duck and quaks like a duck, its a duck." kind of guy so the starter solenoid would have been my first place to check.

This might seem rather neanderthol but in an instance where you have a sticking selonoid, give the thing a good solid tap with a wrench or small hammer. Generally what has happened is the selonoid has gotten old or has been abused by a bad battery where the magnetic switch doesn't quite snap closed and an arc occures essentially welding the contact closed. A good solid tap will generally release the welded contact. Usually the selonoid will work afterward, but you really do need a new one.

By the way - if you have a drain that pulls down a good battery in an hour, that's a hard core drain and something will be hot to the touch. Places to look at would be the starter and the alternator. They are about the only parts of your Jeep that could withstand that kind of drain without burning up instantly. If you haven't been running and you feel heat in the casing of either part you've got a problem with that part. Head lights will also drain a battery fairly quickly, but rarely in an hour and you will likely see the lights on.