Thanks guys, Its just a stock jeep with original equipments, No big loads,I buy a new battery and the alternator charge very well.where are the main earths cable locate.can bad rectifier make heat in the cable.
Best way to check bad earth is to follow the earth cable from the negative side of the battery down.
IMHO ONLY earth cable is either BLACK or BROWN pending on manufacturer.. so for instance on the starter there will be a red (Live OR + )and in general the opposite is BLACK/BROWN on the opposite terminal.
Re reading your post, clean the terminals on the alternator and re tighten and advise.
It's possible yes..it can knock a lot of things out.. I had a car that had a bad MAF (Mass Air Flow Meter) once was looking at a £500+ repair bill.. was told that it needed various parts including MAF. So I traded it for another.. afew weeks later there's my car gleaming on the forecourt. I asked the mechanic what was wrong.. changed out everything, coil packs, sensors, MAF, Lamba Probes (O2 Sensor) the lot, causing a lot of chaos & confusion ..his mate came over for a look and ask what was a wire that was supposed to be attached to the chassis leg doing hanging?? One new earth cable later and car was as good as new so I'm told..old one had corroded through.. So Yes, in effect it could..
The heat is caused by current flow, i would have thought if you have a bad earth it would limit the flow of current and some things wouldn't work (ohms law- increase in resistance lowers the current at a fixed voltage). the charge alternator is capable of putting out a lot of current , you need to put a clamp amp meter on the cable and see how much current is flowing. it may be normal. when you say hot, how hot , power cables are usually ok up to 80 degC then the insulation starts to melt.