Another Alternator problem

[Bobert]

Now I already looked through all the many alternator posts, and I've not been able to figure it out.

First, we got the starter rebuilt after it quit, the same day we put it back in, The Gen 1 light came on bright. So we tested it, got it rebuilt. When we put it in, The light was still on.

We let it sit in the driveway for a month, then I took it up to school to figure it out. A few starts later, the starter relay quit. replaced that.

So all the bulbs are new, and come on right, but gen 1 stays on. Tested both alts, both were about 14-15V. when its running, Batteries are at 28V, gen 2 is at about 14V or maybe it was 28. I put the leads on the same place on gen1 and got 40V???? red wire to valve cover.

All the wires seem to be connected right.

Could it be one of the relays? I have no idea what to try next.

You guys are great and I thank you for your help.

 

[mangus580]

I would start by having that alternator tested again. Sounds like maybe they didnt rebuild it right.

 

[Bobert]

I just got it tested at advaned ap and it was about 15V.

I cant figure out why i got 40 dcV. that's not right anywhere on this thing. I have an analog meter but it was definately 40 ish.

Should I take it back?

 

[CCATLETT1984]

test it again, I dont know where you could have hooked it up to get that voltage, are you sure you had the meter on the correct scale?

 

[GM72K10]

I know it sounds simple, but make sure the belts are tight.(and the right ones)

 

[Bobert]

Will do. I'll be sure to check the belts and the voltmeter.

I think there is a Bosch relay for the gen 2, but is there any relay or fuse for gen 1 that may go bad?

 

[CCATLETT1984]

if the alternator is putting out correctly, then you have an issue in the wiring from the alt to the light in the dash, its the "resistor" that puts a load on the alt so it excites and makes power. the civilian trucks have a actual resistor in the wire so the bulb is not needed.

 

[Bobert]

I think I found the problem. I found a wire that was fried.

It is spliced into a wire that comes from the negative of the rear battery, then goes through the diamond connector and fried the wire going to gen 1. Looks like the one exploded a little. They said something in my alt was really fried.

Do you guys know if there is a fuse in there somewhere or can I just put in new wires?

 

[Bobert]

Heres anothe pic of the Diamond shaped junction dealy.

 

[emmado22]

Thats fuseable link, not wire there.....

 

[Bobert]

Ok, now I replaced the wires and put in new fuses.

When I tried to start it, it sarted and I think the gen 1 light turned off but the started would not stop spinning. I threw the cutoff switch within seconds so nothing fried.

It did this a couple weeks ago, so I replaced the relay and it worked fine except for the gen 1 light.

Then I took out the relay, turned the batteries on, and put the relay back in. and It didnt try to spin the starter. like it did with the key off.


What the heck do I do now? the new fuses and wires are fine

I'm about tired enough to pay somebody to figure it out for me.

 

[Blood_of_Tyrants]

Does it start now?

 

[Bobert]

Nope, I can't get it to start. When I turn the key not even the dash lights come on. it acts like there are no batteries in it.

But everything is back together.

I'm wondering if this could be an ignition switch problem?

 

[Blood_of_Tyrants]

Start at the ignition switch and look for 24 volts on the wire from the battery. If it is there, turn the switch to ON and check for voltage on other terminals.

From the sound of it, you may have fried the contacts on your switch.

 

[CCATLETT1984]

i agree, check the ignition switch, when the starter stuck it could have been the ignition switch or the starter switch that stuck. glad you had a cutt-off switch.

 

[Bobert]

Haven't checked the switch yet. The headlights won't come on either I can't remember but I think you don't need the key in to have the lights on.

I can't get anything to turn on, but I have voltage across various places.

I'm thinking that there may be something between the batteries and everything else. Is there a fuse or relay like that? I'll get to checking the ignition switch , but I am scared to tear apart the steering column.

 

[Bobert]

Thanks for the help guys, I just about fixed it.

it turned out that the fuse I put in between the Neg on the rear battery, and the wiring harness block burned out. I replaced that, and It starts.

And the gen 1 light goes off, and the voltmeter works after I replaced another fuse!

So I started it 3 times and let it idle to make sure everything was alright. However, I let it sit for a couple hours and decided to tighten the belts because they were bouncing a bit.

Now, If I start it, it runs for 8 seconds then dies. The fuses I put in between the rear batt neg and the harness block, and the gen 1 pos and the harness block, keep burning out.

So the problem is narrowed. The wiring diagram shows 2 different ways the wires on the wiring harness block are hookes up. neither are what is on mine. It doesn't make sense to me that the neg from the battery is on the same side as the pos from gen 1.

Maybe i need to think outside the bun?

 

[CCATLETT1984]

can you snap a couple pics showing how yours is hooked up, we can help from there.

 

[CUCVFAN]

So the problem is narrowed. The wiring diagram shows 2 different ways the wires on the wiring harness block are hookes up. neither are what is on mine. It doesn't make sense to me that the neg from the battery is on the same side as the pos from gen 1.

Maybe i need to think outside the bun?

Since the batteries are wired in series, the negative of the rear battery IS the positive of the front battery, which is 12V, just like the junction block. Gen 1 charges the front battery and Gen2 charges the rear battery. What size fuses are you putting in? What is the second fuse you mentioned replacing?

 

[Bobert]

That makes a little more sense, I put 2 In- line fuse holders where the wires fried at the junction block. One goes to the battery and one goes to the gen 1 positive. the other wires are not burned.

Those two I put in 30 amp fuses. I also mentioned I replaced the 24v fuse in the fuse block.

I'll try and get some pictures.