Electrical uh-oh.

[msoumas]

In the process of diagnosing my blower motor's lack of power, my dad and I inadvertently ground out the battery gauge in the dash panel. My M1009 won't start now, it seems like the batteries have been draining with every start and finally gave up. I can jump it and everything will run fine, until I cut the engine. My theory is that I shorted something between that gauge and the batteries. What could have shorted? Could I be lucky and just be out *another* fusible link?

 

[CCATLETT1984]

fusible link on the passenger side alternator.

 

[rizzo]

Re: RE: Electrical uh-oh.

fusible link on the passenger side alternator.

or firewall in the middle ????? that is 12volt one isn't it?

 

[msoumas]

RE: Re: RE: Electrical uh-oh.

No answers after checking fusible links today. Took out both alternators and took them to the local rebuilders today, they told me both alternators are good. What is strange about this is that the batteries are showing 11.something volts each with the truck running and both alts spinning. I don't know yet if they're just not charging, or if there is something actively draining the batteries. I left them hooked up for the night though, so I should know tomorrow, depending on whether or not I need a jump in the morning.

 

[msoumas]

Re: RE: Electrical uh-oh.

fusible link on the passenger side alternator.

or firewall in the middle ????? that is 12volt one isn't it?

The one on the passenger side alt tests ok. I tested all the ones I could SEE on the firewall... are there that I might have missed?

 

[CCATLETT1984]

RE: Re: RE: Electrical uh-oh.

with the truck running measure the voltage at each alternator. driver's side should be !4v and the pass side should be ~28v.

 

[msoumas]

RE: Re: RE: Electrical uh-oh.

Brought the truck back to the rebuilders today. The alternators were working OUTSIDE the truck, but not in it. Turns out the regulators weren't getting any power. Rather than playing the wire-chasing game, we went with the idea of putting in new regulators that don't need an external power source. I guess they're used in farm implements? At any rate, it works this way just fine.

 

[CCATLETT1984]

RE: Re: RE: Electrical uh-oh.

all they need is a sense wire, nothing fancy. The alternator shop should be able to tell you how to wire them in if you dont want to fix your factory wiring issue. Be forwarned, if you modify your wiring and have further issues we will be unable to help you.

Check out the troubleshooting manual thread, the one with the wiring diagrams. You can find the schematics for the charging system and it will show you where you can test to find the fault.

Do the "Gen" lights on the dash light up when you start the truck? The alternators will not charge if the bulbs are burnt out.

 

[msoumas]

Re: RE: Re: RE: Electrical uh-oh.

Do the "Gen" lights on the dash light up when you start the truck? The alternators will not charge if the bulbs are burnt out.

A burnt out bulb could completely immobilize the truck? That seems a little silly, maybe I'm better off bypassing that part of the wiring this way.

 

[CCATLETT1984]

RE: Re: RE: Re: RE: Electrical uh-oh.

Its done on purpose, that way if the bulb is burned out you HAVE to fix it, otherwise you could have an alternator issue and not know it till its too late.

The civilian trucks have a resistor on the wire to the bulbs so the alternator works if the bulb breaks, the military trucks do not have this resistor.