Cucv m1009 drivers alternator not charging

[63bravo]

Ok , will do .

 

[doghead]

Before you install your new relay, test it to confirm it is correct. They look alike and parts guys have been known to take them out of the boxes and get them mixed up.

Better safe, than sorry.

 

[63bravo]

Ok replaced the relay with the st85 napa , Check the glow plugs and they do go off after warm up cycle , this don't make sense , I still wonder the first time I cleaned the bulk head connector the generator started charging but the glow plugs didn't come on ... I'm missing something ..

 

[doghead]

Where all of your GPs ok? 1-3 ohms?

 

[63bravo]

Yes ohm's were to spec , it was charging again for 20 minutes, again I thought I fixed it , the resistor was bypassed by the last owner , removed card and cleaned the contacts replaced the gp relay on the bulkhead , when I shut the truck down than restarted it it stopped charging , I'm pulling my hair out on this one!

 

[cpf240]

Are both alternators the same? IE both isolated-ground alts? If so, try swapping them, and see if the problem follows the alternator. If it does, then you know the alt is, at least, intermittently bad. Otherwise, you can go back to digging into the wiring, etc.

 

[doghead]

I am thinking your alternator regulator is intermittently bad.

I'd rebuild it(replace all internals).

Swapping them is a good idea too, but I like to rebuild(myself) them anytime a truck is new to me.

 

[63bravo]

Well just swapped generators from drivers gen too passenger gen , still not charging on the gen one side , all input voltage is present , don't know ...

 

[Hammy]

I just replaced my alts with two newly rebuilt ones i acquired from a cw3. this guy used to work on the m1008s and told me my alts were bad and to replace them with his. I did and i seem to be having the same problem as 63bravo. neither alts are charging but i know they are good. im going to check the bulkhead and the exciter wires tomorrow. its been about 3 months since this problem started rearing its ugly head. and a snow storm just destroyed St. Louis so I actually need my truck to get to work...

 

[Hammy]

just a thought. any chance the doghead modification to the starter relay could help anything?

 

[63bravo]

you need too check and clean all connections,also check the generator bulbs they must light,make sure the generators are receiving feild voltage at the top plastic push in plug 12 volts and the large lug on the rear of the generator should be 12 volts, clean grounds test batteries ,you also preform voltage drop tests too charging system.

 

[63bravo]

well i finally fixed it for sure ,like you guys said intermittently defective regulator in both generators ,took them both to a old school rebuild shop ,200 bucks well spent .. thanks too every one who helped me

 

[BostonPatriot28]

My gen 1 light comes on as soon as I start it but the moment I touch the throttle it turns off. However I checked both alternators and driver alt is not charging battery so I'm going to remove itand install my rebuilt one. I'm going on a trip this summer I don't want any trouble if I can avoid it. I did replace both batteries this morning which leads me to believe the cause of the broken alternator

 

[BostonPatriot28]

Update on my gen 1 light coming on was bc my alternator failed to charge. Got my backup alternator rebuilt runs perfectly now

My gen 1 light comes on as soon as I start it but the moment I touch the throttle it turns off. However I checked both alternators and driver alt is not charging battery so I'm going to remove itand install my rebuilt one. I'm going on a trip this summer I don't want any trouble if I can avoid it. I did replace both batteries this morning which leads me to believe the cause of the broken alternator

 

[mykey730]

Hey guys i was looking throught this post and i am have a charging problem on gen 1. It all started when i noticed my front battery wasnt charging. And the batteries are new as of 8 months ago and just for laughs at the same time i built a new big set of battery cables. Well just last week i noticed my blower motor wasnt working so i looked and the fuse was blown so i put a new one in and it works fine now. But the front battery isnt charging. So i checked the gen 1 light bulb and cleaned the main firewall fuse plug. I even got the alternator rebuilt. Then i noticed the brown excitor wire on the alternator has the same voltage as the little red constant hot wire on the alternator. Im thinking that is my problem any suggestions would great thanks.

 

[Dpaulson]

Sounds like you have a multimeter and know how to use it.

Okay lets test some items.

Truck off.

Remove the excitor wire plug and check voltage at the small red wire. Should be 12v. The brown wire should be zero volts with the key off and 12v with the key on.

What is the condition of the plug and the two terminals in the alternator? I have seen many trucks that require a good cleaning or even a new plug. (about $5 at the parts house). The terminals in the plug may also need to be tightened.

Remove ground wire and clean the connections at both ends. The terminal at the engine sometimes corrodes.

The large red wire runs to the diamond shaped 12v terminal block on the firewall. Sounds like it is okay along with the fusible link.

On my recently purchased M1009, the passenger side Alt brown exciter wire has 12v with the key off, I cant seem to figure it out because it should be 0v. Any advice on what could cause this issue would be much appreciated.


Thanks for all the good info on this post.

 

[Dpaulson]

Hey guys i was looking throught this post and i am have a charging problem on gen 1. It all started when i noticed my front battery wasnt charging. And the batteries are new as of 8 months ago and just for laughs at the same time i built a new big set of battery cables. Well just last week i noticed my blower motor wasnt working so i looked and the fuse was blown so i put a new one in and it works fine now. But the front battery isnt charging. So i checked the gen 1 light bulb and cleaned the main firewall fuse plug. I even got the alternator rebuilt. Then i noticed the brown excitor wire on the alternator has the same voltage as the little red constant hot wire on the alternator. Im thinking that is my problem any suggestions would great thanks.

I know this post is old, but just curious did you ever get this resolved? I'm Having the same issue and cant figure it out. Thanks.