Archived GEN light on and off

[rckwlkr]

My truck will not hold a charge, it will only start with a jump start after 5-10 minutes of charging time.

After driving the voltmeter slowly drops w/ no stero on.

rapidly drops with headlights on.



I have posted a thread last month and determined the PCM was bad, bought one from TDR member and that fixed the A/C, and idiot lights.



But now after voltmeter drops below red line (10 volts?) the GEN light comes on



With battery charger hooked up I can sit in drivers seat with truck running and plug in battery charger and watch voltmeter climb to 12 or 13 volts and GEN light goes off.

Then I unplug battery charger and the voltmeter drops down and GEN light comes back on.



Finally the QUESTION:

Should I replace the altenator?

I can't find the ground strap that goes from the engine block to the frame where is it?



Thank you very much for the help

 

[Shovelhead]

Could be internaly shorted battery/ies.

How old are they?

Have you had them tested?

 

[Oil Burner]

are you getting 14. 7 volts out of the alternator? if so, i would suspect an internal short also. did you check the fuse (engine control fuse i think) that handles the alternator. i accidentally drilled thru mine and caused the same problem u are describing.

-Jason

 

[rckwlkr]

Not sure how to check alternator output. Please dicribe how to check with my volt meter.



Two new sealed batteries two months old.



Thanks for all the replies-

 

[Shovelhead]

Start the truck, put the + lead on the + terminal, and the - on the - terminal.

Make sure the meter is set on DC volts, and see what its reading. Should be above 13V when running.



See if there is an Alternator fuse, then check it. (should be in the Power Distribution Center under the hood)





If voltage is still lower than 13V, try moving the - lead to the engine block. (that will check for a loose/bad chassis ground. )





If still low, probably a bad Alternator, or Voltage Regulator.



Ed

 

[Oil Burner]

rc,

the back side of the alternator (towards the cab) has the terminals you want to test with your voltmeter. you should have around 13. 5-14. 5 volts. the positive terminal may have a plastic shield over it but i'm not sure. just pull it back to get to a good metal surface if it does. the fuse in in the distrubution center. i think it is called the "engine control fuse" or something like that. let us know how it is going.

-Jason

 

[illflem]

Your symptoms are common when the engine control fuse gets blown by accidentally sparking against the alternator with an oil filter wrench when removing the filter.

 

[esdd]

Same happened to me last Christmas Eve, replaced batteries, no problems since. A shorted battery cell causes pcm to stop charging to batteries, they will charge with a battery charger but not hold verry long. good luck!

 

[TowPro]

Check the fuse as others are saying, Not sure if its in the "outside" fuse box or the one in the dash. I bet its a big fuse outside.



If it is a bad battery, try unhooking one battery, start it and see if it charges better. If not try hooking that one back up, then disconnect the other one.



If they are the original batteries, its time to replace them anyway (doubt there original if its a 95 I think I read)

 

[rckwlkr]

thanks for the help

Hey guys

thanks for all of the help I replaced my alt. and it now is charging and starting great





thanks

neil