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alternator maybe?

H

HogWash

NAXJA Forum User
Location
Murfreesboro, TN
Im wondering if my aternator is telling me something.When I run my heat due to cold mornings when I get off of work,it usually will stay at mid or a little lower,then when I roll down my windows while blower is on it goes down to like 9-10 amps and lights dim down quit a bit,is this normal or should I have it checked out and my battery is 550 cca it came with it when I bought it.I think it sucks
 
this post should be in OEM Tech, but anyway a good alt. should put out about 14.5 volts, the battery should hold at least 13 when not running. If it is droping to 9 or 10 volts you definatly have a problem, could be the alt., bat., or corrosion, bad connection, burnt wire... If you have a VOM it should be easy to diagnose.
 
indianaXJ said:
this post should be in OEM Tech, but anyway a good alt. should put out about 14.5 volts, the battery should hold at least 13 when not running. If it is droping to 9 or 10 volts you definatly have a problem, could be the alt., bat., or corrosion, bad connection, burnt wire... If you have a VOM it should be easy to diagnose.
Click to expand...
I dont but im figureing thats what it is seeings how I use to mud alot and now its catching up.
 
Where do you get your reading from? If it's from the gauge in the dash then don't trust it at all.
When I turn on my AC it drops to about 8V, but using a volt meter on the battery it will be at 12.86V.
Check the voltage your self and don't trust the gauge.
 
my 92 did the same thing until recently
So I cleaned both batt terminals, the engine ground straps, and tightened the serpentine belt, and I've got 2 more volts under load. it used to sag when the blower was running, and with only 1 power window operating.
 
loke said:
Where do you get your reading from? If it's from the gauge in the dash then don't trust it at all.
When I turn on my AC it drops to about 8V, but using a volt meter on the battery it will be at 12.86V.
Check the voltage your self and don't trust the gauge.
Click to expand...
Well when lights are on and heat is on lights dim alot.And rolling down the windows....forget about it.I have to turn my blower off.I believe my battery is a 540 cca.Whats the normal suppose to be?As much as I would love to get an optima,my funds wont alow me to.
 
Definitely a good time to upgrade the cables including the grounds. Make sure all the connections are good and grounds are on nice clean bare metal. The XJ doesn't have the best electrical system but it shouldn't dog out that bad.
 
loke; just because you have a 12.86v reading at the battery and 8v at the gague, doesn't mean that your gague is bad. It means that the alt is charging and the battery is probably good but you could have bad connections, bad motor, or bad wires(high resistance in the circuitry somewhere) try checking the voltage where the gague gets it's reading or where one of the motors hook up to the fuse block inside.
 
i'm in agreement with loke, mine does the same thing, drops down to 8-10 on the gauge with a/c and lights on. although with a meter, she's at 12.5, so like he said, don't trust the gauge, not exactly a highly calibrated unit.. mine's always read 2-3 volts low.

p.s. i blow out the alternator every once in a while and hit it with some wd40 to clear the cr@p out.... all mudded up is hell on the brushes.

is your alt orig? that'd be what? 20 years old, get one from a grand or a dakota... they rock out at @110 at idle...
 
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