A new (maybe) Gen 1 light question

[deank]

Good evening!

I have come across a new to me issue. I have recently put my M1031 back on the road. I noticed yesterday while out running some errands that the Gen 1 light was on dimly.

Voltage guage reads in the green at all times.

A little setup- before the Gen 1 light was noticed I was not able to get the 4WD light to turn off no matter what range was selected.

Today the Gen 1 light was brighter on the way home. Turning off the service lights did not change the brightness of the Gen 1 light.

Turning on the heater blower, the blower did not work and the Gen 1 light was full on (blower worked 2 days before this). No matter what speed was selected. Strangely as soon as I turned on the fan the 4WD light went out.

I have reviewed the schematics, but for the life of me I do not see an electrical connection between any of those devices.

On F9 (page F-11 of the -20) is the only place I see the Gen 1 light in the schematics -and it only shows one wire going to it coming from pin 1 of Gen 1 on the engine.

On F-20 (page F-22 of the -20) the blower motor has it’s own ground.

On F-4 (page F-6 of the -20) the 4WD light only shows one wire from the light going through the switch on the transfer case then to ground in the cab.

I am hoping that someone has seen this before or can read schematics better than I can to help me figure this one out.

Thanks for any help!

 

[vanaisa]

Maybe cucvrus explanation helps you? Higher fan rpm-s, more glow. Charging is OK by voltmeter.

Mine is doing same thing with fan on

Gen 1 Light & heater control

This is odd so I was wondering if any of you have seen this before. I have noticed that sometimes my Gen 1 light is glowing dimly. You can only see it when it is dark out. You can not see it on sunny day. This morning I made the connection to when it is doing this. It was raining and cool this...

www.steelsoldiers.com

 

[Barrman]

There is a ground for just about everything inside the truck up above the parking brake pedal. Your roving electrical problems sure seem to fit a bad ground connection. I suggest you make sure that common ground is clean, tight and all the wires plugging into it are securely plugged in.

 

[Curtisje]

Yup, sounds like a possible grounding issue to me. Maybe the link in my post below will help. It lists the CUCV ground locations. Good luck.

No Power (electrical) SOLVED

I got in my truck last week and turned the key to find no power whatsoever. I had driven it to work that morning and I was busy so I left it and went back to my office. Later on I went back to it, fiddled with the wires on the junction above the glow plug relay and it started so I drove it home...

steelsoldiers.com

 

[WWRD99]

Ground up under the dash way up on he drivers side wall. Gotta get under there pretty good to see it. Probably a little corroded. The blower motor should have a ground from the case of the blower to the ground bar. The gen light could be a bad regulator...need to check volts at each battery.

 

[deank]

I have cleaned the ground under the dash. No change in gremlins. Today I will clean all remaining grounds and add one for the blower motor. I will check voltages after that. If needed I have a spare alt.

 

[deank]

Good morning!
I have been cleaning grounds this morning. All engine compartment grounds are clean and tight. The 6 legged connector under the dash has been cleaned and tightened.

I added a secondary ground to the blower motor (replaced it while I was in there, the original had a squeal, removed the capacitor

Front battery voltage while running : 14.63
Rear battery voltage while running : 14.90

4WD drive light was bright unless the glow plugs were cycling. I moved the transfer through all gears, light never turned off. It may not be the correct switch in the transfer. I have disconnected a wire on the transfer case switch.

All I can think of now is to replace the alt.

ADDENDUM, went to turn off the engine, blower motor was on high. Turned off ignition switch, GEN 1 light went to full on. Restarted and turned off again. Light went full on. Restarted, turned fan off then turned off engine, NO bright GEN 1 light.

 

[deank]

Well, discovered today that the previous owner had installed a non-isolated alternator on the driver’s side. I now have the correct alt installed. All seems to work well. I will check again after dark. Then I will reconnect the 4WD switch.

 

[deank]

It is very dark outside… but the gen 1 light still comes on very dimly when the blower motor is turned on. I just went through my copy of the schematics in color that are posted on this site.

To the SS member that created those, THANK YOU! The schematics in the TM fail to show you where the gen 1 light gets it’s power. The in color version does show where the power comes from. It is the same fuse as the power for the blower motor. Now I know I need to look at the fuse panel to check for a loose fuse or a corroded connection.

Gen 1 light still goes on full bright when blower is on and the ignition switch is turned to off. But that may be normal with the blower on.

 

[ehuppert]

Very common, seen this issue for years, here and elsewhere. Think it's just the way the circuits are. Eventually "fixed" mine by switching in a OEM gauge assembly. Prior though, mine always glowed dimly. Even with dim glow voltage was good. I eventually stopped worrying about it.

Not understanding your last sentence though? Neither blower or gen light should be on with key off?????

Eric

 

[deank]

Light goes full bright when the key gets turned off. When the alt stops turning the light goes out.

 

[deank]

Did some poking around in the fuse panel today. I removed the diode for the horn relay, unrelated to the GEN1 light. Horn seems a little louder.

I did find that the blower motor/Gen1 light fuse is/was melting. I cleaned the contacts really well and put in a new fuse. Hopefully that, and having removed the capacitor on the blower motor and installing a new blower motor will have taken care of the melting issue. Time will tell…

 

[WWRD99]

Did some poking around in the fuse panel today. I removed the diode for the horn relay, unrelated to the GEN1 light. Horn seems a little louder.

I did find that the blower motor/Gen1 light fuse is/was melting. I cleaned the contacts really well and put in a new fuse. Hopefully that, and having removed the capacitor on the blower motor and installing a new blower motor will have taken care of the melting issue. Time will tell…

Yes if you had the capacitor inline on the blower motor still that can backfeed and do weird stuff when they go bad. I have had several on the wiper motor go bad too.