Gen-2 light question......

[Drock]

Ah couple quick questions. I did the HMMWV coolant crossover tube swap ah couple days ago. And now the Gen-2 light will stay on until the high idol turns off and I blip the throttle. When I did the swap I had to remove the passenger side upper alternator bracket ,and swing the alt down out of the way. I also had to remove a ground wire from the drivers side alt. Could this be a ground issue? Does the passenger side alt ground off the bracket?

 

[Warthog]

Does the passenger side alt ground off the bracket?

NO!!!!

The passenger alternator does not use a normal ground. It uses the 12v output from GEN1 as its "ground". Combing the voltages results in the 24v output. This is where the "isolated ground" comes into play.

Check the two pronged plug on the alternator. Many times it is gooie and needs a cleaning. Could also be that you are due for a rebuild.

 

[Drock]

I forgot to mention that when I pulled the heater hose off on that side it dumped some coolant down into that alt. Could this have shorted something out? I also removed the plug and cleaned, greased and reinstalled it today, But no change. Like I said it works fine once the truck warms up. But for some reason I can't make it go off until the high idol goes off.

 

[doghead]

Did you replace the bet and clean the pulleys well after spilling coolant?

 

[Drock]

I don't think it's belt slip.

 

[Drock]

Credit to doghead . The belt is ah little loose and I've ordered a new (shorter) belt. However in the interim I thought I'd give this stuff a try, and it worked!.........http://shop.advanceautoparts.com/p/...7040069-P?searchTerm=electrical+parts+cleaner...... I sprayed about half the can inside the passenger side alt. I figured perhaps the coolant left a residue ,Or dislodged some dust or dirt inside the alt. And this would clean it out. What ever happened this stuff worked. I'll still install the new belt when it comes in...

 

[Drock]

Update, I received and installed the new SHORTER #7480 gates belt for the passenger alt. Now the Gen-2 light goes off all buy it's self without having to blip the throttle. However the Gen-1 light still needs the blip to turn it off. The drivers side alt has the same problem. The belt is too big and adjusted all the way out as far as it will go. So I'll do some more research tonight to find the next size down.

 

[cpf240]

Even the TM's state that the throttle may need to be 'blipped' to get the GEN1 light to go off, so I wouldn't sweat it too much. As I recall, this is about par for the course for vehicles of that era, even when new.

 

[tourus]

so I want to intervene and ask I tried to search but did not have good luck with this simple question the 12 volt red wire from the left alt bolts to where on the right side alt. the positive stud or the ground stud.

 

[Warthog]

Are you asking about your 12v conversion truck or just asking in general?

 

[tourus]

I am asking about my M1028 that is still 24 volt. but it has always had a charging issue. I have check all things I have read about. the only question is that red wire from the left alt. to the right. if it should go on the positive post or the ground post. the truck was in the hands of a state agency before I got it and some of the connections are new. just wondering if they hook it it the correct way or not.

 

[Warthog]

There should not be a wire going directly from one alternator to the other. If so the wiring has been hacked.

The large red wire from Positive stud of the driver side GEN1 goes to the 12v Engine Block by the master cylinder.

From that block, the large Red/White strip wire goes to the "isolated ground" stud on the passenger side GEN2. That is how the alternators are "tied" together.

From the Positive stud on GEN2, the solid large red wire goes to the 24 Positive Terminal Block.

All of this is in the E-9 wiring diagram in the TM 9-2320-289-34 tech manual.

 

[Baer]

More Gen 2 problems. Gen 2 was not putting out enough voltage so I decided to replace the brushes and voltage regulator. Naturally, I forgot to disconnect the batteries so I also got to replace three fuse-able links with the help of AECS (I had the important job of getting him tools). When we fired up the M1008 the Gen 2 light was bright for a brief period then mostly stayed on dimly going bright for a brief period when motor is idling. I noticed that as my RPMs increased the volt meter would climb through the Gen Green to the edge of Gen Red. When checked directly with a volt meter both alternators appear to be charging the batteries (Gen 1 is still putting out slightly higher voltage than Gen 2). I have not yet gone through with a wire brush to clean the contacts or bus bar grounds. What else could it be?

 

[tourus]

ok so I was thinking to day about this. I have a good left hand alternator. that the housing broke so bought a new one from parts place. now that one is having issues . so can I take all of the guts out of the old original alt. and put in the new housing. just a thought

 

[Drock]

ok so I was thinking to day about this. I have a good left hand alternator. that the housing broke so bought a new one from parts place. now that one is having issues . so can I take all of the guts out of the old original alt. and put in the new housing. just a thought

Let me guess you got the new alt from Auto Zone. What I know about electrical wouldn't fill ah thimble, but I'd said pull apart your old one first to see what makes it tick. If it wasn't to complex to get apart, then theoretically those parts should fit in your good housing... That being said, at that point you mite as well just get a rebuild kit and fill your good housing with fresh parts.

 

[Warthog]

Not all the pieces will fit. The housing itself is different and the mounting hardware inside the alternator is different. Not the regulator, diode-trio, rectifier and other parts will be the same.

Didn't the "new" part house alternator come with a warranty?

 

[tourus]

the "new " alt did come with warranty but it is long since gone by. so good info on combining the two will just have to look and find an other cucv style alt. to rebuild. and no it was not auto zone alt.