Help gen1

[M1009_SPAIN]

Hi guys, I need help with my M1009 and the damn Gen1.

I had my Gen1 rebuilt when the light came on, and I verified it wasn't a blown fuse, and that power was reaching the red lead with the key off and the brown lead of the white square connector with the key on.

It worked for two days, and on the third day, the Gen1 light turned on again.

I had my M1008CUCV at home without any issues, so I removed the Gen1 from the M1008 and installed it on the M1009. It worked for one day, and on the second day, the Gen1 light stayed on again and showed 12.8V.

I noticed that when Gen1 and Gen2 are working, both lights on the dash come on at the same time and with the same intensity, and when Gen1 fails, Gen2 comes on more intensely, about a second before Gen1.

I'm having a hard time finding the fault, does anyone have any ideas?

 

[Barrman]

Check the intake manifold end of the ground wire for the alternator. I have had a few of mine get corrosion there and weird things happen.

 

[M1009_SPAIN]

Check the intake manifold end of the ground wire for the alternator. I have had a few of mine get corrosion there and weird things happen

I checked it, cleaned it with a wire brush, cleaned the cable connector... that's why I said I'm out of ideas.

 

[Tow4]

It sounds like you are not sure if it's the alternator or the truck wiring. If you haven't already done the on the vehicle test, then do it. Click Here

If the alternator works in the test, I'd drive it around with the test hook up and see if it works continuously. You can tell if it quits by looking at the volt meter. Just remember to disconnect the test plug when you shut the engine off.

If the alternator is still intermittent, take it off and disassemble it and look for a lose connection. This is one of the easiest alternators to rebuild, all the internal connections are fasteners. Here is the rebuild thread with pictures. Click Here

 

[M1009_SPAIN]

I tested it, and the alternator works. After checking that it was generating 14.8V,

I connected a jumper cable from the red wire of the white exciter connector to the 12V B+ pin. The alternator always generates 14.8V. I checked it with the vehicle's voltmeter and with a manual voltmeter. 14V on the front battery and 29V on the rear battery.

For now, this is the solution I've found.

 

[M1009_SPAIN]

@Tow4

Or do you have any other idea? Thanks to your post, I tested the circuit and found the fault in the red exciter wire.

Would you replace the red exciter wire and remove the jumper I made?

Or would you leave the jumper I made between the red exciter wire and B+?

 

[Tow4]

I would repair the wire and remove the jumper.

 

[M1009_SPAIN]

I would repair the wire and remove the jumper.

Okay, I'll run a new wire from the firewall fuse where the exciter wire starts to the alternator bolt.

the red wire turns orange and they're connected by black plastic. That's not a diode or anything weird, right? I'm referring to using a direct cable.

 

[vanaisa]

Fusible link maybe?

 

[WWRD99]

Okay, I'll run a new wire from the firewall fuse where the exciter wire starts to the alternator bolt.

the red wire turns orange and they're connected by black plastic. That's not a diode or anything weird, right? I'm referring to using a direct cable.

I think the wire you need to repair is the red wire in the 2 pin white connector....tough to tell by reading it. The big wire that is bolted to the back is the voltage output wire that is big and goes to the firewall with a plastic cylinder in it which is a fusible link. If that wire needs repaired it would be where you are talking about with the plastic cylinder which is a fusible link. You should have voltage at that big bolt with the red wire when running...which I think you do as I assume that is the wire you jumped to. You can replace the 2 pin white connector if it is not working right as well.

 

[M1009_SPAIN]

This is the unconnected wire, which is red and comes out of the white connector on the exciter and turns orange when it reaches the fuse. The fuse pin has 12V, but the orange (red) wire that goes to the white alternator plug has 0V.

I made a jumper to the alternator's B+ wire, as I mentioned, and it now charges and works perfectly.

But to replace the cable, I noticed it's red and has black plastic before turning orange, which I imagine is the connection point for both ends of the cable before reaching the metal fuse.

That's why I asked if that was a diode or just a plastic junction between the cable connections.

The work to be done is to use a 1p1019 replacement red wire and connect it to my new 4mm European cable, which is a bit thicker than the 1p1019 replacement, and run it directly to the metal fuse pin on the firewall.

Is that a correct job?

 

[WWRD99]

View attachment 953446

This is the unconnected wire, which is red and comes out of the white connector on the exciter and turns orange when it reaches the fuse. The fuse pin has 12V, but the orange (red) wire that goes to the white alternator plug has 0V.

I made a jumper to the alternator's B+ wire, as I mentioned, and it now charges and works perfectly.

But to replace the cable, I noticed it's red and has black plastic before turning orange, which I imagine is the connection point for both ends of the cable before reaching the metal fuse.

That's why I asked if that was a diode or just a plastic junction between the cable connections.

The work to be done is to use a 1p1019 replacement red wire and connect it to my new 4mm European cable, which is a bit thicker than the 1p1019 replacement, and run it directly to the metal fuse pin on the firewall.

Is that a correct job?

Perfect. That black cylinder has a number on it that tells you the guage of the fusible link that it is. It might have a 16 or 18 on it depending on size...thats all that cylinder does...its a marker/indicator. I'm not sure about the alternator side though as to what is not connected? Unless you mean this wire in the pic is supposed to go to the 2 pin connector on the alternator? I think that's what you described in the post. I'd have to look at one of mine quick to see or look at the wiring diagram to be sure if that's supposed to be hooked up there. Ok...I just looked...that wire does go to the constant power on the 2 pin plug on the alternator...it has a 20 stamped into the plastic cylinder. So the fix is to make sure you have power to the 2 pin connector from that wire...it may have melted the fusible link. I pull on the link to see if it's good. Some don't melt all the way and have a few strands still connected. You can get a piece of fusible link in 20 guage and crimp that in tight. That gets power all the time so replacing that feed wire might be a good idea. Doesn't look hard. Can tape a new wire to the old one and pull it through. Just get the same guage or bigger if need be. I'm curious as to how it got disconnected from the 2 pin connector?


Side note, the block on the firewall is not a fuse. It is only a junction block to combine all the 12 volt wires going to all the 12 volt components in the truck. The fuse is the first 8 to 10 inches of the wire hooked to it. That is the fusible link up to the black cylinder on the wire.

Looking at your picture again you are pointing to the fusible link with 0 volts marked on it. It should have power all the time which leads me to think the fusible link burned up. If you have 12 volts at the junction block then the fusible link should also...I'm not sure if you have that wire where you are so I can't help on where to get some.

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[WWRD99]

View attachment 953446

This is the unconnected wire, which is red and comes out of the white connector on the exciter and turns orange when it reaches the fuse. The fuse pin has 12V, but the orange (red) wire that goes to the white alternator plug has 0V.

I made a jumper to the alternator's B+ wire, as I mentioned, and it now charges and works perfectly.

But to replace the cable, I noticed it's red and has black plastic before turning orange, which I imagine is the connection point for both ends of the cable before reaching the metal fuse.

That's why I asked if that was a diode or just a plastic junction between the cable connections.

The work to be done is to use a 1p1019 replacement red wire and connect it to my new 4mm European cable, which is a bit thicker than the 1p1019 replacement, and run it directly to the metal fuse pin on the firewall.

Is that a correct job?

I zoomed in on your pic and you can see where the red insulation on the wire is almost gone. That is probably where the fusible link is burned. Give that a tug and it'll probably pull out. In a pinch you can cut that out and attach it back to the other end for a quick fix but still want to replace it. My big concern will be why did it burn as it would need a short to ground or a larger load than rated for to burn.

 

[WWRD99]

View attachment 953446

This is the unconnected wire, which is red and comes out of the white connector on the exciter and turns orange when it reaches the fuse. The fuse pin has 12V, but the orange (red) wire that goes to the white alternator plug has 0V.

I made a jumper to the alternator's B+ wire, as I mentioned, and it now charges and works perfectly.

But to replace the cable, I noticed it's red and has black plastic before turning orange, which I imagine is the connection point for both ends of the cable before reaching the metal fuse.

That's why I asked if that was a diode or just a plastic junction between the cable connections.

The work to be done is to use a 1p1019 replacement red wire and connect it to my new 4mm European cable, which is a bit thicker than the 1p1019 replacement, and run it directly to the metal fuse pin on the firewall.

Is that a correct job?

Reading your original post about swapping alternators to another truck and it failed as well I would say something in that alternator is not right. I think you state it was just rebuilt so to me it sounds like the regulator is faulty when it gets hot or an insulator inside is touching the case when it gets hot or vibrates from running. I'd be curious if the other truck burned the same fusible link as well. If so, I would not run the alternator you had rebuilt and take it back to where it was done and see if they can fix it.

 

[M1009_SPAIN]

Indeed, the black plastic, which you say is a fuse, has a 20V rating. I've looked at it closely, and the color change looks like dirt. I'm going to remove it and see if it has continuity.

From the beginning of the cable to the end of the white connector, there's no 12V, so the Gen 1 light is dimmer than Gen 2 when I turn it on. However, with the Gen 1 jumper cable, it's the same brightness as Gen 2, and Gen 1 produces 14.8V.

Is the black plastic a fuse?

Can I run a direct cable from the junction block to the terminal of the small red wire (the exciter, which always has 12V on Gen 1) of the Gen 1's 2-pin white connector without any problem?

My intention is to install a cable that can withstand 70 degrees, a nominal voltage of 450/750V, and a test voltage of 2500V. Is that correct? This cable is thicker than the original.

 

[WWRD99]

Indeed, the black plastic, which you say is a fuse, has a 20V rating. I've looked at it closely, and the color change looks like dirt. I'm going to remove it and see if it has continuity.

From the beginning of the cable to the end of the white connector, there's no 12V, so the Gen 1 light is dimmer than Gen 2 when I turn it on. However, with the Gen 1 jumper cable, it's the same brightness as Gen 2, and Gen 1 produces 14.8V.

Is the black plastic a fuse?

Can I run a direct cable from the junction block to the terminal of the small red wire (the exciter, which always has 12V on Gen 1) of the Gen 1's 2-pin white connector without any problem?

My intention is to install a cable that can withstand 70 degrees, a nominal voltage of 450/750V, and a test voltage of 2500V. Is that correct? This cable is thicker than the original.

We're almost there. I think it's a touch of a language barrier and how wires are sized between our countries. No problem though. The plastic cylinder is just a marker, not a fuse. The wire itself, is the fuse...here we call them a fusible link. If it is over loaded it melts to break the power going to the alternator, just like a fuse in the fuse box. You have them all over the truck at each point of power connection on the 24 volt bar and the 12 volt bar this wire is hooked to. The wire with the 20 on it only indicates how big it is...thickness or strand count. The tough part will be finding some where you are. Possibly google fusible link where you are and see if any parts stores have it in a gauge similar to the 20 size that is in it now in your country. You can replace the entire wire to the alternator with a larger wire but you will need that fusible link to protect the alternator and all 12 volt systems if it fails. Seeing the gen 0ne light is not as bright as gen 2 light tells me there are maybe one or 2 strands of fusible link left so not enough current can flow to get the alternator to charge. I do think the rebuilt alternator is the problem or as the car people here say the causal part of failure.

 

[M1009_SPAIN]

I understand. I think the original wirecable with 20 refers to AWG 20. The one I bought for installation is equivalent in the US to AWG 12, with a higher strand count and ohm resistance. That's why I'm asking if you think that's correct.

Thanks.

 

[WWRD99]

I understand. I think the original wirecable with 20 refers to AWG 20. The one I bought for installation is equivalent in the US to AWG 12, with a higher strand count and ohm resistance. That's why I'm asking if you think that's correct.

Thanks.

I don't see why you can't go bigger. The main point I need you to understand is....the wire from the 12 volt block to the plastic part....is a fuse....not a normal 20 awg wire. It must be replaced with the same 20 awg fusible link wire that is there now.

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[M1009_SPAIN]

I don't see why you can't go bigger. The main point I need you to understand is....the wire from the 12 volt block to the plastic part....is a fuse....not a normal 20 awg wire. It must be replaced with the same 20 awg fusible link wire that is there now.

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I understand it's not just a wire,

what are you referring to? https://www.sherco-auto.com/products/fusible-link-16-gauge-general-use-orange

Or that I should install a fuse like the ones in the 20-amp fuse box inside the wire.

Did I understand correctly?

 

[WWRD99]

I understand it's not just a wire,

what are you referring to? https://www.sherco-auto.com/products/fusible-link-16-gauge-general-use-orange

Or that I should install a fuse like the ones in the 20-amp fuse box inside the wire.

Did I understand correctly?

Thats it just need one with a 20 awg on it!

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