M1009 Gen2 light flickers.

[MasterSweeper]

Trying to help out a friend in need. A good friend of mine has a M1009, after spraying some engine Gunk cleaner and rinsing off with a water hose his Gen 2 light flickers when he is driving it. He said that he let the engine dry before starting it up. Here is a few things I checked for him,,, alternator 1 is putting out 14.4 volts and alternator 2 (passenger side) is putting out 14.6 volts so they seem to be charging fine. The volt gauge on the dash reads in the normal green area. Both gen lights come on when you first turn the key on and both go off when the engine fires up. He has two brand new batteries that both load tested good. The first thing I told him to do is let it dry out for a few days and see what happens. Three days latter and the gen2 light still flickers. It only flickers when he is driving not sitting at idle. I did look through the TM but could not find his problem. The last thing we tried was cleaning the fire wall harness plug, it looked real clean but we cleaned some of that black goop off the terminals, that did not help at all. Any thoughts????

 

[Warthog]

Sounds like the voltage regulator may be on the way out. 14.6v is slightly high. See if he can hook up some long leads and test the voltage while driving.

 

[MasterSweeper]

I can do that, when i tested it at idle it was going back and forth from 14.6 to 14.7.

 

[Barrman]

Also check for loose connectors on the back of the alternator. Both positive and negative. I agree the regulator probably is the issue. However, I had a slight flicker only when driving on some roads. I ignored it. After a few weeks it happened anytime I moved the truck. Turns out the bolt in positive lead to the back of the alternator was loose inside the alternator. A new fiber washer, tightened stud inside and all was well again.

 

[MasterSweeper]

OK, I had a chance to go back to my friends house. First thing we did was clean both buss bars and clean all the ring terminals, then check for continuity with a wiring schematic. Well it was a start but did not fix the problem. So the next thing was the passenger side alternator came off to take a look inside. I installed a new voltage regulator and cleaned all the connections. Yes Barrman those connections you talked about were loose. Well im not sure if the voltage regulator or the loose dirty connections was the problem but all is good now. We took the truck out for a hour ride and the light never flicked. So thanks Barrman and Warthog from the both of us.

 

[Warthog]

Great news. Glad we could help out.

 

[marchplumber]

Wow! Steelsoldiers helping one another!! One of the reasons this site is great!! Inspires the "Can Do!" Attitude. Thanks!