I thought I'd go a head and post up what I found out on the "Battery Light" issue that I'd been dealing with for the past few days. I did a search here first, but came up empty handed. Basically It ended up being a bad fuse, the (#6 fuse) in the Fuse box thats located in the engine compartment. Nowhere did this ever come up in the threads that I searched thru, so I figured I needed to post this up. I actually got a new Alternator think'n this was my issue. I checked all the wires for crack's, shorts, bad grounding etc, but came up with nothing. So I installed a new Alternator. It didn't cost me anything as it was still under warranty. I thought it was just a Diode that had gone out, or maybe the internal Regulator that went out. It was showing charging spikes anywhere from 14.3 to 15.3, so naturally I figured it was bad. A quick fuse change, and down the road I went. Anyhow, I hope this info can help some one else down the line. If this was posted previously by someone else, then my sincerist apologies to that person. God BLess, and Happy New Year.

 

Thanks for the info. Reps sent.

My 99 manual designates it as Diesel only - Single or Dual Alternator "A" Field Regulator. Probably why you were seeing the voltage spikes.

 

Good info. I don't think I've seen this before.

Take care.

 

Thanks for the heads up!!

 

Man I am going to have to take a look at that fuse. mine spikes all the time, and seems like more that 15.3. It will actually make the headlights noticably brighter when it spikes.
thanks Iwas getting ready to buy a new Alt. hope this is my problem as well.

 

Countrycar what were the symptoms of your truck was it just the light coming on? I'm having a problem with my truck not being dead in the morning but the guage is down on the first line of the guage then when it starts up for a few seconds it goes up to where it is supposed to be.

 

The Battery Light came on last week while my 17 yr old son was driving the truck. He said it started normally and ran normally, and that it was sitting at 14.2 -/+ volts while driving down the road. I drove it the next day to and from work, and noticed that it was charging out of control. As high as 15.3, up and then down to normal range, all with in seconds. So I assumed it was the Voltage Regulator that had gone out with in the Alternator itself. I didn't notice any other symtoms while driving. I hope this helps yah out some Derek.

On Edit: Derek, when I first start my truck the needle of the dash gauge is on the bottom as well, then it'll jump right up with in 2 +/- seconds. I also have a Scanguagell that's mounted in my truck, and when I first start the truck, and while idling, it'll show around 12 +/- volts for the first 60 seconds, then the Alternator will Excite internally, and it'll jump right up to 14.1-14.3. This is normal operation of our trucks charging system. The factory gauges are really very tough to use as a reference to diagnose a problem with our trucks. Usually by the time you notice a fluctuaion in the factory gauges indicating that there is a problem, it's to late. It sounds as though your system is working properly. Unless your Battery light is on, then you do have a problem. Generaly anywhere from a short, A bad battery/batteries, and or Alternator.

 

Hey Joe. Were you able to find out, whether this was your problem as well. The fuse I mean.

 

Not yet. Spent the day with the wife and kids and the Movie Tin Tin (joy) anyway I am taking tomorrow off and will take a look at it, but my symptoms sound the same. Not sure to actual voltage because I dont have a meter but it would spike to the upper line which I would think would be over 15v for sure. Will chime in tomorrow.

 

My bad. its been awhile for this thread.
Well I checked the number 6 fuse and it seemed to be just fine (dang it) so now my blinking light and spiking voltage is still there.
I am still thinking it might be a faulty regulator in the alt.
any more ideas?????

 

. Run it to the autoparts store and have them test it for yah. I'm think'n the same, the Regulator is bad.

 

if you are getting voltage spikes you could cause alot of damage to your electrical sytem so you might need to get a volt meter to confirm asap some have bought $ 15.00 ones at walmart that plug into your lighter socket my voltage is 12.6v next morning, 11.3 when keys turned on with glow plugs , then back to 12.6 or 12.5 v when glow plugs cycle off, then 10.5v while cranking, 13.5v with engine running