No "GEN 2" Light On Power Up. How to test?

[MuddWeiser]

When I turn the key to the ON position prior to starting the vehicle (waiting for wait light to turn off) my Gen 1 and Oil light come on but the Gen 2 light does not come on. I was thinking it may be a dead light bulb BUT my voltmeter doesn't move at all. Even when the vehicle is running it just hangs all the way to the left (batt drain).

COULD THESE TWO PROBLEMS BE RELATED? Or is it more likely I have a shorted voltmeter wire AND a burnt out Gen 2 warning Light bulb...

 

[mangus580]

Well, first things first... Please add your location to your profile as specified on the FAQ's on the left.

First thing you might want to check, is the voltmeter fuse, in the fuse box. Also look at all the connections on the back of the passenger side alternator to make sure all is snug. If the voltmeter still doesnt work, check the wires feeding it, with a Multimeter to see if there is power there (power means voltmeter is bad) While you have the dash apart checking that, you can slap a new bulb in the Gen2 light and see if that helps the problem. I dont think the 2 are actually related though.


If you need more help, I can check in the TM and the schematic to try and help diagnose it some more if need be.

 

[n1vbn]

When I turn the key to the ON position prior to starting the vehicle (waiting for wait light to turn off) my Gen 1 and Oil light come on but the Gen 2 light does not come on. I was thinking it may be a dead light bulb BUT my voltmeter doesn't move at all. Even when the vehicle is running it just hangs all the way to the left (batt drain).

COULD THESE TWO PROBLEMS BE RELATED? Or is it more likely I have a shorted voltmeter wire AND a burnt out Gen 2 warning Light bulb...

OK. this isn't rocket science.

Check that the alternator belt for the paasenger side is intact and not thrown off pulley? Belt OK? Go to two.

2 No idiot light for Generator two? Stop at auto parts and buy a couple of ata style 10 amp fuses. Take one in hand and look at fuse block...see round thingiee on bottom right of fuse block? That is your flasher for the turn signals You will see anodder rounmd thingiee up inna top left hand corner...this is the four way flasher. Now think like the fuse block is a clock face...at the 9 O'clock position using the flasher as a "clock face"remove 10 amp fuse probably burned out....replace with new 10 amp fuse....turn key on and VOILA!!!! Number 2 generator light is on if the light isn't burned out..if the light comes on start the engine and rev it up to shut off the idiot lights...hey lookit the volt meter!!!! It's in the green!!!

The Army specified no diode installed on the idiot light to keep the alternator charging when the light burned out No light? no chaergee battery!!!...this was so the soldier would have to go to the motor pool to get it fixed instead of ignoring it.


Mine did the same exact thing when I took delivery of the M-1009...the local civilian mechanic (?) told me the number two alternator was junk...$.20 for a new fuse and the "JUNK" alternator is still working fine.

By the way you just replaced the only 24 volt fuse in the entire vehicle with a 10 amp 12 volt fuse exactly like I did.

If your number two battery is way down charge wise don't be surprised if it takes a while for the voltage to hit the "notch" which indicates 28 volts where both batterys are fully charged.

Voltmeter don't move at all? Not uncommon mine was unplugged and didn't work until we plugged it in then it worked fine ever since.

 

[CCATLETT1984]

neither of my gen lights come on with the key, I know they worked a few months ago as they clued me in on the fact that my alt's needed some TLC. My voltmeter started acting funny about 3 o 4 months ago and then finally quit a while back, the truck still charges great.
I've been lazy and haven't checked for the 10amp fuse yet.

 

[Armada]

Now think like the fuse block is a clock face...at the 9 O'clock position using the flasher as a "clock face"remove 10 amp fuse probably burned out....replace with new 10 amp fuse....turn key on and VOILA!!!! Number 2 generator light is on if the light isn't burned out

What if the fuse is good and the bulb is good, and the light still will not come on? Gen puts out too.

 

[CCATLETT1984]

There are fusible links on each gen, they send the voltage to the lights. I had a loose connection of gen #1 and the link on gen #2 needed to be replaced. both of them now work fine

 

[jeepin]

>>What if the fuse is good and the bulb is good, and the light still will not come on? Gen puts out too.

The other thing to remember is that there are two relays under the dash for Gen2 and the voltmeter. There is no such relay for Gen 1. On my CUCV gen 2 lite was out and turned out relay was bad. This relay is located behind heater controls in center of dash.

 

[rgguin]

I had the same problem Gen 2 light did not come on when I turned the key and when I cranked it the voltmeter stays in the yellow area. Today I replaced bad rear battery and pulled the Gen 2 relay and Voltmeter relay. Both are besided each other under the lower dash to the right of the steering column. I went to NAPA and bought two new ones since mine sounded like something was loose inside them. Put both in and cranked M1009. Volmeter is still in yellow, Gen 2 light now works, but stays on. I am getting 14.5 volts to the front battery and 12.5 volts on rear battery while idling. Appears rear battery is not charging. I did the trouble shooting in the manual that said to remove the connector from right side alternator and turn key to run. Gen 2 light did not come on. Manual says to trace wire from alternator to GEN 2 light, if wire good replace alternator. How do you trace the wire, most of it is wraped and bundle with all of the others? Do I need to take the fuse box loose and look behind it for frayed wire? It said use figure #4 in the manual to trace wire. What besides the fusible links are usually the problem with the Blazer wiring?

 

[ida34]

How do you trace the wire, most of it is wraped and bundle with all of the others? Do I need to take the fuse box loose and look behind it for frayed wire? It said use figure #4 in the manual to trace wire. What besides the fusible links are usually the problem with the Blazer wiring?

I have a handing little unit that attached to a wire then you use a pencil type receiver to follow the circuit. Having said that the easier way to do it is to find correct terminal on the printed circuit board in the dash and run a continuity tester between the terminal at the alternator and the terminal at the dash for the light. If the tester shows continuity then you don't need to do anything else. If it does not have continuity then you need to start trying to find the short. Again my electronic gadget helps with this because I can find the break when I loose the signal while tracing the wire. I got this thing at Lowe's and it works great for tracing circuits.

Remember that the alt needs the resistance provided by the bulb in the idiot light to energize the field on the alt. This can be done with a resistor or the resistance provided by an idiot light. I am not sure how this related to you situation but an alternator can loose a diode and it will charge just enough to make it look like it is working but the voltage will be low enough not to fully charge the battery. You may have a diode out. Take the thing off and take it in to be load tested. Remember to tell them that it is an isolated ground and have them ground the machine on the ground terminal. At least I think it is alt 2 that is the one that uses the isolated ground.

 

[Armada]

Got my gen 2 light working again last week. The #2 alternator I had rebuilt lost it's regulator. Shop put a new one in, it was still under warranty. It's all good now. I have finally eliminated all the bugs. Fuel, glowplugs, starting and charging are 100% and all stock. I put a few hours on it this past weekend with no probs.

 

[rgguin]

Update: Got my Gen 2 light working, but would like opinions on what happened. I replaced both the voltmeter and Gen2 relays under the dash. This did not solve anything. Voltmeter was stilll in the yellow and 12.5 volts at rear battery. Pulled rebuilt alternator #2 and took it to alternator shop. It was putting out nothing when they tested it. They found bad regulator. While putting it back together the fellow said he had never seen one wired like it. I said all I know to tell you is it has a external ground. He wanted me to know he was putting it back together as he found it. He tested it and it put out 14.5 volts. I put the laternator back in and got a surprise when I went to connect the battery leads. I put the front battery negative on first, then when I put the front positive cable on the alternator popped and I thought I saw a spark?? I noticed the battery lead from the rear battery was touch the battery bracket so I thought maybe it grounded out? I put the negatvie lead on the rear and when I put the last lead on the rear battery positive terminal I got another loud pop fromt eh alternator? Well I thought I muct have ruined the new regulator, but i cranked it up and all my problems were solved. Voltmeter is now in the green, but only about a 1/4 of the way. Gen 2 light is now off. I have heard a relay click in and out about three times when I first crank the Blazer and I notice that each time it clicks the voltemeter swings from green to yellow and back? This has happened the last three times I have cranked it. Checked voltage at both batteries and they were 14.5. Today I cranked it up and the Gen 2 light blinked at idle speed. When I slightly reved up the engine it stayed off. Voltmeter was still the same 1/4 the way in the green. The rear battery voltage was swinging at idle speed from 14.26 to 14.5. I drove the Blazer around town and the Gen 2 light only came on and blinked when I had to stop for red lights. Later I had parked and got back in it. This time no blinking Gen 2 light and both batteries are steady with 14.3 volts at idle. What caused the pop when hooking up battery leads? I had connected and disconnected them before the alternator was repaired and never heard a pop. Is 14.3 volts going to be OK?

Thanks for any help!

 

[ida34]

Are you sure the click while you are cranking is not the glow plug relay. I can tell when my plugs are on because they will draw the voltage down into the top of the yellow region then when they go off the needle goes back to green. I don't know about the other stuff.

 

[rgguin]

Chuck the three clicks of the relay are happening after I get the Blazer cranked. Each time it clicks the voltmeter is affected. After the relay operates the last time then the voltmeter returns to green. It does not do it while driving.

 

[CCATLETT1984]

I would recommend running your GP relay to a manual switch to see if your controller card is on the fritz. Search for previous posts, or PM me and i will walk you through it.

 

[cucvrus]

OK. this isn't rocket science.

Check that the alternator belt for the paasenger side is intact and not thrown off pulley? Belt OK? Go to two.

2 No idiot light for Generator two? Stop at auto parts and buy a couple of ata style 10 amp fuses. Take one in hand and look at fuse block...see round thingiee on bottom right of fuse block? That is your flasher for the turn signals You will see anodder rounmd thingiee up inna top left hand corner...this is the four way flasher. Now think like the fuse block is a clock face...at the 9 O'clock position using the flasher as a "clock face"remove 10 amp fuse probably burned out....replace with new 10 amp fuse....turn key on and VOILA!!!! Number 2 generator light is on if the light isn't burned out..if the light comes on start the engine and rev it up to shut off the idiot lights...hey lookit the volt meter!!!! It's in the green!!!

OK Old Post but does someone have a picture of the fuse box that shows the 10 amp fuse at 9 o'clock. I am not near the CUCV but am trying to do my homework before shop time begins. I have a no current to Gen 2 situation to diagnose and repair. Bulb is good and links are good. No current to cluster thru main cluster harness.

 

[joshuak]

... OK Old Post but does someone have a picture of the fuse box that shows the 10 amp fuse at 9 o'clock. I am not near the CUCV but am trying to do my homework before shop time begins. I have a no current to Gen 2 situation to diagnose and repair. Bulb is good and links are good. No current to cluster thru main cluster harness.

#12 I believe, got it from here.



Good luck.

 

[cucvrus]

Yea I read further. That 10 amp is at 7 o'clock if I were to put a crooked clock face on the fuse box. I thought my memory was failing again. I will conquer this problem tonight. Expect a report.

 

[cucvrus]

Gen 2 light is fixed. It was a bad 10 amp fuse. Imagine that. The fuse looked good and the voltmeter worked but the fuse was bad. Took a flashlight under the fuse to see the break. More a corrosive break than a blow fuse.

 

[cucvrus]

Working like a boss.

 

[joshuak]

Gen 2 light is fixed. It was a bad 10 amp fuse. Imagine that. The fuse looked good and the voltmeter worked but the fuse was bad. Took a flashlight under the fuse to see the break. More a corrosive break than a blow fuse.

I like fixed, good job.