Snap and dead after turning the ignition

[IronVarmint]

The 2001 TJ was driving fine on Saturday for lunch, but wouldn't start a few hours later. Turned the key and dash lit up, but heard a snap when I tried to start it, and then everything went out (see video). It's repeatable: if I wait over a half hour it will light up again and snap.

• Voltmeter shows 12v on the battery (this is a 2 month old battery, too).
• Checked all the fuses. I replaced #2 and #7 anyhow because I couldn't tell whether they were bad through the worn plastic.
• The dash lights and the hood lamp are bright before cranking. Radio works.
• Key in accessory and in run light up everything fine--until cranking.
• My ohmmeter is toast and I'll have to buy another to check resistance on relays.

If everything still worked after turning the key, I'd say check the starter and relay next. Any time saving ideas?

Edit: video loop

 

[por212]

Check voltage down stream of your battery post. Seem like a bad connection at the battery terminal.

 

[GaTechTJ]

Check voltage down stream of your battery post. Seem like a bad connection at the battery terminal.

I agree. I had a similar problem about a year ago. Turned out to be a bad connection on the negative battery terminal. I found it by turning on the headlights and check the voltage on battery terminals vs on the connectors. Terminals showed 12 volts. Connectors showed almost nothing with a load on them.

 

[IronVarmint]

I agree. I had a similar problem about a year ago. Turned out to be a bad connection on the negative battery terminal. I found it by turning on the headlights and check the voltage on battery terminals vs on the connectors. Terminals showed 12 volts. Connectors showed almost nothing with a load on them.

Great tip. It was a bad connection on the positive. Thanks!

 

[AdelaideTJ]

I think it's a good idea to replace both battery terminals when this happens, they are usually sold together and only a few dollars to replace. I've found when they are old it can be easy to keep a spanner handy and just tighten when the issue happens again, but after a while they often get warped from overtightening/temperature cycles and you can't make a good connection anymore no matter how much you tighten the bolt.

One day you'll be in an inconvenient spot and find yourself trying to stuff some aluminium foil from your lunch in between the terminal and post just to facilitate a decent connection and wish you'd just spent $5 and 5 minutes swapping them out!