Crackers TJ

[cracker]

Since Big Dogs the battery has been dying in the Jeep.. jump it and drive it a bit and it would be good for a few days.. I figured something was draining it.. last night I jumped it and watched the volt gauge.. it was pegged at 19 for a bit...then dropped to 0 for a bit...then pegged at 19 for a bit... over and over.. Does that mean the Alt is dead?

[etk300ex]

Most likely but battery may cause odd issues too.  Disconnect the batt with in running and watch.

[Wingman]

I'd try a fresh battery first, or at least a different one from something else.

[M4wdFab]

start, disconnect, measure alternator output.  should be 14.7ish

[cracker]

ok stupid question.. do I just disconnect the + cable from the battery then put the meter between the + cable and the - terminal of the battery?

[M4wdFab]

ya

[M4wdFab]

dont lick anything 

[KingtheZJ]

Don't let the hot touch the chassis/ground

[cracker]

Well jumped it then the meter read about 12.5 between the battery posts, but if i put the probes on the clamps it read 0.  Unhooked the positive and it was still 0.

So does that mean it is the alt?

[etk300ex]

Rip alternator

[etk300ex]

Wait wait wait, it reads 0 on the terminal still hooked to the battery?

[cracker]

Wait wait wait, it reads 0 on the terminal still hooked to the battery?

yes.. if the probes are directly on the posts it read 12+, move to the terminal clamps(still attached to battery) and it went to 0.

[luvmyxj]

clean your posts and clamps you should still have 12 at the clamps if your battery is full

[mr.mindless]

Posts and clamps should be the same if everything is hooked up. Clean 'er!!


Tapatalking in traffic

[etk300ex]

Yeah try it again.  I don't think posts could possibly be that corroded. 
Regardless your alt is hosed.