I wonder if the '99's have a battery light since you have the gauge in the dash. On the '02's, they replaced the voltmeter in the dash with the useless tranny temp gauge.

 

I see a batt light when I start the truck. I may have not been paying enough attention to see the one in the dash when my alt went bye-bye. I sure noticed when the A/C quit though! Couldn't roll down the windows either... that was a fun 30 minutes or so.

 

I am not 100% sure it is a bad alternator.

Drove about 3 miles to parents house to use their garage. Battery light stayed on steady when rpms where up. At idle, the battery light flickered. Turned off truck to run in their house. Restarted truck to pull into their garage. The battery light did not come on. DVM reads 13.20 volts. Now the alternator is charging.


Decided to replace the alternator anyway as I got a good deal on a brand new (not reman) Bosch alternator. Disconnect positive cables on each battery. Load test each battery - 12volts no load, above 10 volts with load. Held the load tester switch down for a while. Both batteries seem fine. RR and alternator, checked all connections including grounds. Grounds are grounded to block. Clean off grease/grime on connections.
New alternator puts out 13.20v at idle. Batteries might be low from driving 43+ miles with battery light on - 12.10v.
Decide to wiggle harness from ignition key again. Door chime chimes when no key is in the ignition and the drivers door is open again. Take off lower steering column cover. Blow out dirt with air compressor. Chime still chiming when door is open with no key in the ignition. Cut and tape black with pink wire.


After idling for a while, 14.25 at idle at both batteries. With headlights on, driver side battery is 13.20v and passenger side is 14.25v???????? Why aren't they equal when they are under a load?

So now I am wondering if the heavy rains we have been having caused/contributed to my charging problem. I inspected the fuse box and surrounding for dampness and found none. Didn't find any rust under the dash either.

Was it really a bad alternator that started working again right before I removed it? I am tempted to take the old alternator to a shop that can test it.

Thoughts????

Thanks everyone for your help.

Neil

 

Looks like you fixed it.Look at your post in green above.

 

I agree that the charging system is behaving correctly right now but.....

Right before I removed the old alternator, it started charging. It was putting out 13.20v at idle and 12.99v with the headlights on. I was hesitant to change it but decided that I don't want to pay to get towed home, don't want to change the alternator on the side of the road, already had the new alternator, etc. Bottom line, the $150.00 for a new alternator seemed like good insurance. But why would a alternator that was only outputting a max of 12.10v suddenly start charging? Was it a problem with ignition (key cylinder or switch)? Was it that the rain had stopped and the truck had dried out?

I been having problems with my door chime chiming when there is no key in the ignition or no lights on, etc. If I wiggle the ignition locking cylinder or the harness connector under the dash, I got the chime to behave correctly. Now I am not sure the locking cylinder or that harness has anything to do with the charging system. I will say that the no charging happened a couple of day and a couple of hundred miles after me wiggling things. Still, I don't believe in coincedence. I like to rule them out if possible.

So, I guess as you say, if it is isn't broke don't fix it, in this case, as long as the charging system is working correctly I'll be happy. I have never seen an intermittent alternator. I do have the old alternator and would like to have it bench tested. If for nothing else, peace of mind and for future reference.

Thanks...

Neil

 

13.2 is not "charging". It's VERY marginal at best. 12.99 with the headlights on is also very dismal. If you were to test the current output (what actually does the work), you might be surprised to find maybe 20-30 amps at the most.

I know how an alternator works, and I know how the regulator that controls output works. It is very possible to have an intermittent no charge condition, a somewhat charge condition, and a malfunction light with either condition.

 

Cody,

What range of charge do you like to see? I've heard that anything from 13.5 to 14.8.


FYI, the truck ran fine today with the A/C on.

Thanks...

Neil