I bow to the Jeep gurus again:
I have a love/hate relationship with the durn thing. It's my not-so-daily driver. Used to go to town. Work vehicle sees nasty roads and I try to keep my better set of wheels off of them. It maybe has had 2k miles put in it over the last year.
so 97 Gr Cher limited 5.2 auto with all the goodies. Has had the t-care replaced w part time one, rad, heater core, water pump, carpet, one heated seat replaced in the last few years.
On the way home from town last week it did some funky transmission shift. (it's been shifting wonky occasionally esp when wet/damp out) then the volts gauge went to zero...nada....nothing. looked like the key was off. Called the kid to come follow us home...charge the battery if needed. Ya know that limp it home thing rather than pay the tow truck!
Since it ran home fine we just parked it (making sure battery was charged) since it was bitter cold. Really didn't need to use so no biggie til it warmed up some.
Did a little bit of google reading. Decided to change the alternator. Went to local pickapart. found a fresh kill in a dodge Dakota that was a recent rebuild. Put it on and still nothing...gauge goes up to 13ish and drops back to zip/zero/nadda. Shut it down, went to restart and battery was dead. barely cranked/clicked.
Put battery charger on it for 2 minutes and it fired right up. read battery voltage in the dash, unhook the charger and Blam...back to zero... WTF?? Pull neg wire off battery while running (I don't want to hear about frying PCM<we know its a possibility) truck runs but idles a bit slower than usual.
Tomorrow the alt is coming back off and going on the kids college beater. in 10 yrs the only time that ol heep o jeep has left me stranded was when the starter died...ohhh and the fuel pump. Not bad for a 318 powered heep w 300k on it.
Should I look into PCM, Battery cables (they are iffy) . I know I should also look into dash cluster wiring as the dash was out for heater core.
What really gets me is it ready voltage w charger on it then nothing when charger disconnected.
Battery is fairly new. haven't had any problems with starting when its bitter cold or holding a charge for a week this time of year. Its also the go-to battery to put in our bulldozer when we need to use that. And that is a hard start.
What to look at??
Editing to add: Key on, not running....reads battery voltage..upon starting it drops to zero.
One more add. The security system no longer seems to function. dead or weak battery used to make all the bells whistles and lights blare.