Overcharging randomly

[Nacademus]

Hello all,

My m1008 has been overcharging intermittently lately. Every time I drive it, I notice my blower motor blow harder, sometimes my lights and gauges brighten when driving at night.

Up until recently, my amp gauge wasn't working. I soldered 3 1W 100 ohm resistors in series and now it works great. When I notice the overcharge, my gauge kisses the high red bar beyond the green... when the alternator light comes on, the needle is at the low to middle green part of the gauge. Usually, I get no overcharge and no light. Gauge shows 3/4 into the green.

Now, I just went outside to take some voltage readings.


***********************************************|
With truck/ign off, I got...

Back battery: 12.89V
Front Battery: 12.76V
Combined: 25.7V

Gen 2 (positive stud to alt housing): 25.7V
Gen 1 (positive stud to alt housing): 12.76V

With key ON but not running I get...

Back battery: 12.6V
Front Battery: 12.5V
Combined: 25.3V

With truck RUNNING, I got...

Back battery: 14.4V STEADY
Front Battery: 13.42-15.40V Not steady.
Combined, 25.7V

Gen 2 (positive stud to alt housing): 27.3V
Gen 1 (positive stud to alt housing): 12.8V

Now, when I fiddle with the black/white wire on the driver's side alt, it sounds like its putting a load on the engine. Like its charging.

I am not certain if it loads because I move THAT wire specifically, or because I am tweaking the positive lead above it. I plan to put new eyelets on the ends of the leads to make sure this isn't the problem.



I replaced the underdash relays. Both of them. Driver's side generator is brand new- Autozone PN# I found here. Generator 1 is rebuilt with the CUCV Electric kit. It didn't charge at all before-seems like it is the most stable one now.



Any guidance as to what I could be missing? At idle, it seems like my generator gauge overcharges more predictably than while rolling-but it does happen when rolling.

I had a plug-in 12v outlet battery monitor in the cab and it would overcharge and show 16V on occassion. Then my lights would illuminate more. It would setting down to 12.8 sometimes... then remain at 14.5. Its really strange.

I need some help here.
I greatly appreciate any advice of insight you can offer.

Thank you!

 

[Keith_J]

You are on the right track, the black and white wires signal the regulator of the battery voltage which then varies the output voltage to maintain battery charge.

 

[4x4 Forever]

Check your batteries (load tested) and connections real good.

Although it might be a voltage regulator, I have seen the same happen with a battery fixing to go out, undercharged, or gone.

 

[4x4 Forever]

double posted...

 

[Nacademus]

I have replaced the batteries, the issue still happens.

I have replaced the connectors on the driver's side alternator-the one that gets the strange readings. Same issue.

My next step is to pull out the alternator and swap it for another one. I had the DL7157 already in the truck. This is the one acting up.

 

[Warthog]

I say the new autozone alternator is bad. Why did you use it instead of a stock unit?

 

[Nacademus]

Honestly, because the price of stock units scared me away. I guess I could have rebuilt it. I rebuilt the passenger side one and it works great.


Hindsight is 20/20 I ought to look for a stock unit that I can rebuild on the cheap. I don't trust these AZ alts anymore.

 

[Nacademus]

Well. Replaced alternator. No light. Not even a flick er. Generator gauge stays near the top of the green. Doesn't move. All is well.

 

[donalloy1]

PENETROXTM A-13 every single terminal landing on vehicle and observe the magic!