Engine/Transmission (1994 - 1998) Altenator not charging?

[CAROLINA CUMMINS]

My family just bought a new(to us) truck, and I think the alternator may be shot. Worked alright until I was headed for town and had all the lights, and radio on. It reads about 8-10 volts, and will noticeably move down when the lights are turned on, when this happens the "Check Guages" light comes on. When I turn all of the lights off, the CG light will go off. Totally killed the batteries. Any Ideas???

98 12v 224,000mi



Steve

 

[McCRam]

You might be right. You can go to your local parts store and they should be able to tell you if it is bad or not.

 

[ndurbin]

I had an altenator checked at a local store and it checked out fine but would not charge on the truck. You might cycle the key w/o starting it acouple times (on-off-on-off-on I believe is the sequence) and watch the check engine light flash and see what codes it gives you.



Nathan

 

[Jschafer]

From watching this site and my own experience the original altinator will go out around 180k give or take 20k that said I would put a new one on it, if you think it is the original, I am not a Autozone fan but I got mine there as it was the only place that had one at the time and that now has 130k on it without any problem.

 

[LHastings]

Check the 120 amp fuse by the fuse box under the hood mine was blown and low voltage did not show up for about a week until the batteries started going down.

 

[Bhale]

I just put one in mine a month ago. (178,000 miles) I bought a rebuilt one from Salvo auto parts (local discount place) and it wasn't right, charging would go from 8 volts to 14 volts and cause the GEN light to come on. Took it to my mechanic and he said "did you by a rebuilt POC?



He ordered me a new for $175 and all is well.



One other thing to check real quick, unplug the sensor for the intake air temp. It's just behind where the square intake manifold enters the block. If the sensor is bad it'll keep telling the PCM to charge the air intake heater grid which is an 80 amp draw. Unplug it and let the engine idle for several minutes, preferably with the engine at operating temp.



Good Luck



Brian

 

[Willys]

Have you done any tinkering under the hood lately? Does the tach work? While changing my water pump I bumped the connector for the engine speed sensor, and the alt. didnt charge. Zip ties keep it tight. Do some searching on the site, there is a lot here...

 

[Forrest Nearing]

the night I bought my truck, the charge light was on...



next day, I cleaned all the battery terminals and replaced the hot cable between the batteries. haven't had a problem since.



Forrest

 

[CAROLINA CUMMINS]

Well, it was the alternator. we determined this finally after we hooked up a charger to the batteries and took the belt off and cranked the truck and let it run for a little bit. The gauges worked fine so I replaced the alt. and she charges perfect now.



Thanks, Steve