I have a 1993 ZJ that won't let batteries hold a charge overnight. I can jump them, they'll run all day, but once they sit, it drains. The vehicle had a remote start system I had suspected, so I removed two 30 amp fuses from the power input on the Remote start module. For about two weeks, the battery held a charge and would start whenever I wanted it to. All of a sudden, it's draining again. I have no clue where to start.

 

Check the started solenoid.

 

I've been wondering about that too. It really sounds horrible when the starter engages, like it's not operating right. Any way I can test the starter and solenoid?? But would that drain the battery anyway? The solenoid and starter aren't constantly engaged.. that's what the ignition is for, correct?

 

No if the solenoid is bad or going bad it was cause a constant draw from the battery. I've replaced literally hundreds on Ford truck/suvs

 

I'm totally stumped. Try to turn it over, and it sounds like one normal crank, then frantic ticking for as long as I hold the key in the ignition position.

 

first check that you have ample battery power to turn the engine over, a good battery should hold at around 13.2 volts with the engine off. if your battery has good voltage, make sure theres no corrosion on the terminals. could be giving you a bad connection. after that, its probably the starter and/or solenoid.

we learned in auto tech last week that a constant draw can be caused by battery acid leaking out and seeping down the battery and making conect with a ground, causing the power to drain like that.

 

How do you figure? I'm just curious, not challenging you, I don't know hardly anything about diagnosing electrical systems.

 

How old is the battery? It may be time to replace it.

 

I've tried two different batteries. One I had in my last jeep before I rolled it 2.5 years (Napa gold, never had a single problem) and a very much newer Summit Racing battery that came in the ZJ. Both drain, and both have the same symptoms while in the Jeep. That's why I don't think it's a battery problem.

 

Neither of my batteries leak. The terminals were the first thing I changed, and the posts were the second thing I polished and cleaned. The battery had 12.46 V when I tested it earlier with the engine off, after trying to crank it multiple times and having it not start.

 

post a video of what its doing as far as not starting, if you can

 

What does the voltage drop to when you crank the engine over? Anything under 9.6 volts while cranking means the battery is junk.

 

X2 on what Bustedback said

 

pull the IOD fuse out

 

Is this under the hood in that box or under the dash?
And I'm not sure what the Voltage is when I'm cranking, I'll have to test that tomorrow on the batteries.