when I turn the key on my '96 xj, it just clicks and all the lights go out and power to the whole vehicle dies. The battery reads 13 volts so we're pretty sure it's good. The battery accepts and holds a charge from a battery charger fine. I took it on a long drive/adventure with my gf only like an hour before. While trying to fix it with her dad he started switching relays around in the power distribution center under the hood. Switching one around caused the lights to come back on and everything (dome light, headlights, fog lights) to work fine. But as soon as I turn the key everything goes out. Also trying to turn on my 4 roof mounted lights kills everything as well. Any help or suggestions of what exactly might be wrong are appreciated. Thanks.

 

How old is the battery and have you had it tested at all?

 

And will anything stay on with just the key on without trying to start it? Like having the radio on?

 

Like I said, the battery is reading around 13 volts on the terminals. Everything turns on lights, radio, etc. but as soon as I try to start the car, everything goes out. If I wait an hour or so and come back, the lights work again but are killed the instant I turn the key. Even though the battery reads 13 volts, could it still be bad in some way? Idk how old it is, I haven't even had the jeep for a year yet.

 

Well your best bet at this point is to take the battery to get tested. It will still hold a "charge" if it's bad but as soon as you put a load to it, it will not have enough juice to supply the needed current. Start with that then see what happens.

 

Check your engine/chassis grounds. A bad ground will cause the same symptoms. Also check your battery wires for corrosion beneath the insulation. There are posts on this forum regarding this and how to correct.
hope this helps

 

Update: as of now I've taken both the starter and the battery in to the auto parts store to be tested. Both are good. I've tested all the relays and they all seem to be good as well (they click on and have almost no resistance on the multimeter). They only thing I can think of now would be to check the battery wires, the ignition switch, the neutral safety switch?, and a guy at the parts store said it might be the crank position sensor or something like that idk. Thanks for all the help so far and please keep the suggestions coming in, I appreciate it!

 

Test your crank position sensor:

https://www.cherokeeforum.com/f51/testing-cps-5563/

Do you have reverse lights when the ignition is on and you put the vehicle in reverse? Test and repair your NSS:

 

Alright well... I put the battery and the relays and the starter all back in, connected everything up and gave it another go just for fun and it started right up. Haha idk what was wrong or if it's still broken and it will just do this again later soooooo for now things are solved I guess. I will most likely be testing the crank position sensor anyway. Thanks for all the help guys!

 

Might want to go ahead and check your battery cables and your grounds. Sounds like that might be your gremlin. If it is, you will have reoccurring problems in the close future if you don't do anything. And Jeeps are notorious for acting up when they are far away from home....