altenator issues

[Pookapotamus]

having some problems with my 95 xj, last couple of weeks when i stop at a light or just idle and have my lights on or heater on high my voltage drops below 10v. so i figured the old 90 amp alt was on its way out. last night my voltage was even lower so i got an 136 amp alt out of a zj (thanks fraser) and swapped that in today. no change its still doing the same thing! johnny thought it might be the battery so we swapped in his, still no change. then figured it was the voltage regulator and i had a couple sitting around and swapped that out, still no change! i still sit at just above 9v on idle if i have my lights on.

the 4.ol is not idling too low or anything like that but what am i missing?? what else could be causing this? and yes i guess it is possible that the zj alt is bad too but it worked fine in frasers when it was taken out. (although i think it might have been in the jeep that fraser wrecked, dont know if that would kill the alt.

so whats my next step?

[Vinman]

Check the ground connections, specifically the cable that runs from the engine to the firewall and the wire that runs from the battery to the fender well.

Vince

[w squared]

Check the ground connections, specifically the cable that runs from the engine to the firewall and the wire that runs from the battery to the fender well.

Vince

I was going to suggest the same thing - ground issue.

[Pookapotamus]

i was thinking that too just did not want to re wire! 

[01sahara]

Buy a TJ we don't cook the altenator on every puddle. 

[cLAY]

Are you checking the voltage with a mulitmeter or the dash gauge? Whats the voltage at the battery and the post on the alt? Could have a bad cable.

[Pookapotamus]

i have only checked it with the dash gauge, i know something is wrong as all my lights dim pretty badly. i am going to pick up some wire and connectors in the am and get to work see if i cant fix this. thanks for the advice all!

[cLAY]

Pick up a multimeter while you are at it. Otherwise its hard to say where the problem is and you're just throwing parts at it.

[Pookapotamus]

well i ended up replacing every wire related to the charging circuit, redid all the grounds, supplies and alt wiring. they were not visably bad but did not test well with the ohm meter. runs better now still noticing some drop in voltage with everything i can turn on, around a 1v drop at idle.

thanks for all the advice.

Pook

[specialk]

Buy a TJ we don't cook the altenator on every puddle. 

and SHA-ZAAM!

[w squared]

Buy a TJ we don't cook the altenator on every puddle. 

Pook wouldn't know what to do if his vehicle's "frame" stopped flexing. After all, that represents 25% of his suspension travel. 

[Pookapotamus]

you guys are so funny! 

so this worked fine in the garage but driving the wife to school this morning it was doing the same thing! now what?

[Knox]

I have a multi meter in the jeep right now actually, I can stop by on my way home if you'd like to borrow it.

[Pookapotamus]

i have one, but thanks. stop by anyway i have a socket for you.

[FiEND]

not that many things to go wrong in that area.

alternator
wiring
regulator
shorted battery (watch temp).

isn't the voltage regulator an external one, in the ECU, on the 1995?  should throw a code?