Gen 2 light going on/off among other things..

[Dabba]

Hello, quick question. (And ive searched) My gen 2 light is coming on and off intermittenly, sometimes staying on if i have the truck parked, though can rev the motor and itll turn back off. Sometimes the voltmeter will actually show in increase in the volts then what its suppose to be when it begins flashing. Looking at other threads.. i take it the regulator is going bad?

Other things ive noticed that may or may not be related... The rear battery... the postive terminal area is corroding a bit with white stuff around the contacts (going to clean that today) I actually had the truck not give me any power when i went to start it one time, messed with that wire and it was fine, so that needs a cleaning..

The other thing is, behind the air filter on the firewalls, theres a plate. And from behind that plate ive noticed a black wire poking out with a ring contact on the end of it, like its supposed to be bolted down... But, its just loose, and looks like its never been connected. I didnt want to screw with it, because i have no idea what it is. Id like to show you guys a picture but.. its not available at the moment. I can only guess it was hidden behind this plate the entire time and then came loose. Any ideas? Thanks guys

 

[319]

FIrst, start by checking your belts. Make sure they are tight, but not too tight.
Second, where does the other end of the wire with the ring terminal go?

 

[Dabba]

Honestly i havent looked yet. Not sure if its just bolts and honestly its hot and im really shot I guess i should look though right? haha. And the belts are sufficently tight.

 

[Dabba]

Got a picture, anyone know? It looks like its actually a red wire.. (But who knows)

 

[Matt65]

That is a 24V wire that goes to a resitor behind that plate. It steps 24V down to 12V for the Glow Plug relay. This alows single hookup slave jump starting.

 

[Dabba]

So, if it stays disconnect.. its fine for the truck? How would it be used? Its suppose to attach to the slave term on the grille or..?

 

[Barrman]

If your glow plugs work, then your resistor has been bypassed. Don't worry about it right now since it has nothing to do with the ALT 2 light.

You wrote that you have searched. Did you download the manuals and look through the huge troubleshooting section of the -20 manual? That should be the first place to look on these trucks when it comes to issues.

The rear battery is the one charged by the passenger side alternator. Pull the terminals off, clean them and put it back on. Make sure you tighten everything down. Clean all the terminals on the batteries while you have it apart. Follow each and every wire from the batteries and clean the terminals where they go next. Hook everything back up and see if your problem is fixed.

 

[Dabba]

Thanks, will do! So.. my glowplugs.. suppose to be 24v? and are they still? Its only for jumping other trucks right?

 

[Matt65]

Thanks, will do! So.. my glowplugs.. suppose to be 24v? and are they still? Its only for jumping other trucks right?

The GPs are 12V. The slave connection on the passenger side of the grill is used for jump starting, and using 24V tools that plug into it.

 

[Dabba]

So if mine is bypassed.. theyre 24v? im a little confused. And i cleaned up the contact real good on the battery. Put it all back together and she only blinked once, then i drove around and couldnt get her to reproduce the problem so ill keep my eye on it..

Although.... the little plastic plug is slightly melted on the top. Doesnt seem that bad but i guess that could be it. I had to replace the other one on the dside alt when i changed it. What is it for? and where could i get a replacement? Thanks guys. Dside alt was recently rebuild so if the other one is going im not surprised.

Oh! and for some reason, my cucv always has a habit of corroding that same postive term on the rear battery, none of the others. Anyone have similar issues? thanks

 

[Warthog]

The plastic plug on the alternators is for the excitor circuit. Bad plug equals no juice from the alt.

They are available at any parts store. The wire colors will be different, so cut and splice one wire at a time.

 

[Dabba]

Thanks man

 

[Barrman]

Yeah, those little plastic plugs are what makes the alternator work. Get new ones for maybe $5.00 a set.

The glow plugs stock were 12 volts. So other vehicles could slave start your dead truck, both batteries feed the glow plug system. The big "plate" on the firewall is actually a resistor that steps the 24 volts down to 12 volts. Moving two wires will bypass the resistor and make the glow plugs run off just the front battery.

 

[Dabba]

ah. so theyre still 12v, just go off the front batt instead of going from both thats reduced to 12. So, what is my rear battery doing now then?

 

[mistaken1]

ah. so theyre still 12v, just go off the front batt instead of going from both thats reduced to 12. So, what is my rear battery doing now then?

Evidently nothing unless it is still providing the second half of the 24V needed to turn the 24V starter (assuming you have one).

You really should download and read the manuals.

 

[Dabba]

Oh yes, duh, forgot about the starter.. Kinda got sidetracked thinking of the plugs.

 

[mistaken1]

Oh yes, duh, forgot about the starter.. Kinda got sidetracked thinking of the plugs.

My senior moments are growing in frequency so I can relate.

 

[Dabba]

heh. Well, i cleaned up all the contact, and even tightend the belt, because i noticed it was a little loose. Still comes on and off. I noticed it goes on and off when im driving, but if it comes on when the truck is stopped, itll stay on until i rev the motor. If she comes on at a stop, the voltmeter drops accordingly, if she blinks on and off while im moving, the meter spikes. Could the alt just be going, or the clutch that suppose to engage the alt when you first start the motor and rev it be going? Seems like its legitimately cutting in and out.

the only thing im thinking is that plug that looks a little burned up.. but for all i know it could have been like that forever. First order of bussiness is replacing that... but while im down at autozone, i think i should just have them test the alt? its just a normal 12v alt right? Anything different then normal alts? If its bad i have a guy to rebuild it.

 

[Dabba]

Also guys could you link me to the appropiate tm? im clicking the ones on the wiki at the top of the forums, but they just send me back to the main site. Also any tips how i can test the alt if i can get my hands on a voltmeter myself? id rather not have to take it off the truck and bring it to autozone, something tells me their results wont be reliable

 

[Dabba]

Is it as simple as running a voltmeter across the rear battery when the truck is runing? haha