Gen 1 light came on

[cliffyp]

My Gen 1 light has always come on at start up and would go out as soon as I gave the accelerator a little juice, or if I started with half throttle it would go out immediately.

I'm sure it's unrelated, I changed the oil with my 3 year old. He wanted to work on the truck with daddy and it was due anyway. After we finished, I cranked her up. Everything normal, both Gen lights turn off when it starts up. I leave it idling to come up to temp. A few minutes later I hop in the cab and Gen 1 is lit up.

I check the TM.

I don't have the means at the moment to check idle as #1 calls for, but it sounds normal. Rev the engine or idle, Gen 1 stays on. Proceed to step #2

I disconnect the connector from Gen 1, lights out, so I guess I'm tracing a circuit over the weekend although I'm guessing my alt just took a poop.

Anything else I should be checking or should I just go ahead and order a rebuild kit from CUCV Electric?

 

[Warthog]

Sounds like it is time for a rebuild. The wiring circuit as you described it seems to be working fine.

 

[gungearz]

I would drive it locally for a bit.... To see if it goes out naturally. I don't know how a oil change could've triggered it. Unless your luck is like mine. Something big goes out when you finally get cought up on things.

 

[MarcusOReallyus]

If an electrical component is going to die, the stress of start-up is usually what will finally kill it.

It's likely your alt was on its last legs, and this one more start was enough to finish it off.

Nothing to do with the oil change, unless the little guy was messing with some wires while you were crawling around down under.

Not that little boys are ever goign to do anything like that, of course. Well, at least, not mine. Nooo, mine would never do something like that!

 

[M1008driver]

When the light comes on I would not even trouble shoot, just rebuild or replace. That's where it is going anyways...

 

[cliffyp]

Thanks for all the advice. I figured I'd be rebuilding the alt.
Here's the next question: CUCV Electric has a "basic" rebuild kit and a "complete" rebuild kit. Any recommendations on which kit? The "complete" kit is a bit more than double the price. Will the "basic" kit get the job done or should I just opt for the "complete" kit?

 

[gungearz]

Always, alwats, always buy a complete kit. You never want to cheat your work... Just to get so far and it takes a poop again....

 

[cliffyp]

Sounds good. I guess I'll get the combo set and rebuild both. If one went out, the other's probably not too far behind.

 

[cliffyp]

Ok, so I got my rebuild kit from cucvelectric.com. I rebuilt My driver's side alternator. Pretty simple process. Alternator is back in. Gen 1 light is still on. Back to square one.

There is 12+ coming out of the alternator, the old one was probably working too, but it didn't hurt to rebuild it. As per the TM I disconnected the connector from the alternator and turn key to "run", and just like with the old alt, Gen 1 light is off, so I need to trace the circuit between the alt and the light in the instrument panel. I guess I should have just followed to TM and not jumped ahead.

Here's my question though, since the alt is putting out the correct voltage, is it charging the battery and the problem is just with the wiring to the Gen light, or is that voltage not actually making to the battery?

 

[Skinny]

If you haven't reman'd the alternators yourself and the previous owner didn't show proof, do both with complete kits for piece of mind.

Time and money well spent!

 

[cliffyp]

Yes, I ordered the combo set so I could rebuild both. I've only rebuilt driver's alt since Gen 1 is the light that is on. I'll rebuild passenger side alt at some point, like you say, for peace of mind, however I don't have peace of mind after rebuilding Gen 1 because the light is still on.

 

[Barrman]

Put both leads of a volt meter on the front battery with the engine off. 12.6 volts is a fully charged battery at rest. You should have 12.0 or higher.

Start the engine and see what you have at the front battery. 14.4 volts is a full battery with a working alternator. With everything off, you should be at least 13.8 volts and climbing with the engine running right after start up. Anything below 13.0 and your system still has a problem.

You didn't by chance turn the heater fan on and leave it there? I know, you live in the tropics but most of these trucks have a glowing to shining ALT 1 when the heater fan is on hi. Does the heater fan work? Have you checked the ground at the top of the parking brake mount? That ground has something to do with just about everything on the truck directly or indirectly.

Finally, did you check the old components of your alternator to see what was bad?

 

[cliffyp]

Since Gen 1 light first came on, the truck has been started 5 or 6 times. When the engine is off, both batteries read 12.5v. With engine running, rear battery reads 14.5v, but front battery still reads 12.5v. It appears the front battery isn't getting a charge, but it also hasn't gone down at all with the handful of starts.

My heater core has been bypassed because it was leaking in the floorboard and I don't need heat. The blower does work fine though. I put it to full blast and it didn't change any readings.

As to the ground at the parking break, I'm not very experience with electrical, how do you test a ground?

The volt meter on the dash is reading right between green and yellow.

I did not test any of the old components from the alt. I do still have them though, I suspect that they were working fine and were not the cause of the Gen 1 coming on.

 

[Barrman]

The best way to check the ground is pull the bolt out, clean each wire end and the mounting surface. Then put it back on tight.

 

[maxpowercheck]

I did read a discussion on this topic with troubleshooting in the FAQ's. Seems the Gen gauge itself can have influence on the system. I would look at the posted 'cheat sheet' and one of the other quide sheets that have been posted. There are troubleshooting answers in there. Of note, my 1028 tried to catch on fire 3 times. Replace your battery terminals if they have any wear at all! Use heavy duty commercial ones. Put new copper leads on the wires and clean your battery posts. Make sure they are snug. Important, tighten every nut on the 2 relay panels behind the rear battery (on firewall). Disconnect batteries beforehand......During starting mine shot flames off 2 battery posts because I had poor connectivity somewhere. Melted the posts (repairable I'm told) but reverse energized the batteries and they swelled. The addage about cleaning anything electrical is absolutely the god honest truth. Check all ground wires and mounting points. Ensure they are tight. Put a tool on it! Get a multimeter and get electrical! I learned the hard way. Disconnect your ground wires first. (Question of my own) Does anyone know if the Alt 2 light bulb can be replaced?

 

[MakersTeleMark]

The lightbulb is an easy replacement. You might be able to reach underneath to get to it without pulling the dash.

On another note, I'm having Gen 1 light problems myself. Batteries fully charged, when it starts up getting 14.5 volts at the front battery. After a minute or two, gen 1 light comes on, voltmeter on dash and at battery reflects no charging. Driving around with the Gen 1 light on, it will randomly go out, and I can see that the front battery is charging. Always charging after startup, but always comes on while driving for a few minutes. Any thoughts anyone?

 

[cliffyp]

My only guess would be a bad connection, either in the alternator or along the circuit somewhere. See if you still have 14 at the back of the alt when your Gen 1 light is on. I guess you just need to determine wether it's the alternator or the circuit.

 

[erniemigi]

I to had a similiar problem, gen 1 would stay on but gen 2 would never come on, i went ahead and rebuilt both gens and still had the problem, i called up a buddy of mine who was in the army and dealt with the cucv's and he told me to pull the gauge cluster out and check every light bulb and to clean all the copper leads and contact points to, did all that and did find a couple blown bulbs, put it all back together and everything worked great, gen lights came on at start up and quickly turned off, both gens are putting out the correct voltage, now i'm not sure if this is the gremlin that you are chasing to but i figured i let you know what i did to fix my problem, i trust my buddy as he has been around and worked on them for alot of years, he said "sometimes you just got to throw the TMs out the window and try something new and if it works write that down just in case" hope it all goes good for you and you find the gremlin and shoot his ass

 

[cliffyp]

I appreciate the info. I'll give it a try!

 

[Corvette1974]

Check for corrosion on everything, especially the bulb holders for the Gen lights. Even though your light works, i'd still check em. If You have the original military alternators (both are isolated ground) try changing the driver side with the passenger side. that will tell you if it is an alternator problem. And maybe you'll stir up some bad ground/connections at the same time.

Will