gen 2 light intermittent on..

[ragedracer]

I looked at all the threads in search, and didn't find anything that really fits my issue, so I thought I'd ask the collective mind here and see what y'all think.

I took my '09 on its first "big" trip. About 200 miles each way, with an overall elevation gain of ~10,000'. First, it ran GREAT!! Even with all the hills, and running about 65mph the whole way, I got about 17mpg. I added some gauges (water temp and oil press.) The water temp varied from ~205f on the uphills, held steady 195f on straightaways, and dipped to ~170f when going down long grades. Oil press. was ~58-60psi at all times when warm and under throttle. ~40psi at idle. So, I'm happy there! 4wd worked great and pulled me through some deep snow, and my new GP's (ssdieselsupply.com SSD-070) had it firing up on the first cycle even at ~25f.

Now, here's the problem/issue. On the way home today, I noticed some GEN 2 light issues. When I would be under load, then release the throttle the light would come on for a second or 2. It also flashed on when I would honk the horn, turn on a directional blinker, or even turn on the high beams. It would never stay on for more than a second or 2.

What could be the issue? Is the alternator going bad? Loose belt? (seems tight) Or some other issue? The driver alt (GEN 1) is basically brand new. Can I swap them and see if the GEN 1 light starts coming on?

Last ?... I remember reading that one of the alt's can be a standard civvy alternator. Which one can that be? Driver or Passenger? Since I have a brand new military version on the driver's side, I can buy a civvy alt and move them around to correct positions right? If so, which one goes where?

Thanks guys! Lot of thoughts pouring out in one post!

rr

 

[Michael]

Drivers side is grounded to the frame. It is always a good idea to check to be sure the ground is isolated before you hook up the passenger side alternator. Sounds like a loose or old belt to me. If it seems tight does it look good; is it shinny or cracked? Next step is to check the output voltage of the passenger alternator.

 

[ragedracer]

I don't know the belt's age. It is the belt that came on it out of the military. I checked the voltage and I am getting ~28v at idle from the pass. alt. I guess the first thing then would be to replace the belt. I guess I should just replace them all anyway. None of them look bad, but who knows for sure..

rr

 

[mangus580]

Mine has been doing something along those lines since I got it 4 years ago. Kinda fades in, comes to full bright for about a second and turns off.... Its totally random, I havent been able to see any pattern to it, and have not bothered to worry about it anymore at this point.

 

[Michael]

I am getting ~28v at idle from the pass. alt.

rr

No, you are getting 28v from both alt. You need to know how much the pass. alt is putting out. there are several ways to find out and even different opinions on exactly what range of readings is considered normal.

You can take total voltage and subtract the drivers side voltage from it, you can measure across the ground stud and the pos stud at the alternator or my favorite is to measure across the battery posts of each battery. The back battery is being charged by the passenger side alternator. I use 14 to 14.7 volts as an acceptable range. The TM allows up to 15 volts measured at the alternator. Anything less than 14 and the battery will never reach full charge.

 

[m4A1]

My gen 2 light comes on when I exceed 60 mph and stays on until I slow down to idle and rev the engine. Anyone have any ideas? (Besides dont go faster than 60)