FJowners.com

after riding my fj around for about 2 hours the headlight got dim and stranded me on the side of the road..so when i got home i charged it and the next day put a volt meter to it with key off im getting 12.6 volts key on 12.4 idle 12.3 and 4k 12.5 volts..where should i start? if voltage regulator how do i check it? whats weird is when i bought it the battery was dead and i jumped it and rode it home 30 miles and it actually charged the battery...so now im stumped 2nd time this season it has stranded me

Start simple and basic.  Clean all the battery connections well.  Clean the ground at the rear of the engine.  And check the connection on the heavy red wire coming from the alternator - this connection seems to build some corosion and adds enough resistance to create enough heat to melt the connector!

After that have the battery tested and then the charging system. 

Good luck and let us know what you find!

ok i checked all connections ground was a bit dirty so i cleaned it up still no change though..where to now

You're not getting any charging current from the alternator to the battery.
Check the AC voltage (red and brown) wires coming out of the alternator.
Check all the fuses, including the separate "main" fuse.
Check and clean all the electrical connections between the alternator and the battery.
The rectifier/regulator could be bad, but I wouldn't replace it until you've checked all the other possibilities.

Electrical problems can be a bitch to find.

Arnie

A service manual helps.

Is there anyway to check the regulator? All connections are good and fuses any type of relay or other common problem that would cause this