GEN1 light issues

[addinquir]

I wanted to chime in if its OK.
Still related but different problem.
My GEN1 light does not light when in ignition/starting mode.
All batteries are fine, all alternators are fine.
Voltmeter reads nothing but I think its because somehow in the past I broke the capacitor that jumps between the positive and negative bus....I read a post on why its there and it was supposedly for the voltmeter. I forgot the value in farads of the capacitor but I think it should be replaced and maybe magically the voltmeter will start working again.
Anyway those two problems are not alarming to me as much as the following:
When I shift the 4WD from 2WD HIGH to 4WD LOW, during normal engine running, the GEN1 light lights up!!!!!
That is alarming.
Any ideas on any of the above especially the last one?
Thanks.

 

[Warthog]

Welcome to the site.

Moved to your own thread.

Define "fine" for your batteries and alternators? What is your voltage readings on each battery when the truck is running and shutdown?

Does your heater work?

 

[cpf240]

Don't know why the GEN 1 light would come on when the 4WD lever is moved, but..

The capacitor between the 24v buss bars is just a noise filter and has nothing to do with the voltmeter, and is not needed unless you are getting alternator noise on the radio. I'd suggest that either the voltmeter is bad, or the voltmeter relay, next to the GEN 2 and starter relays, is not working.

 

[addinquir]

Thanks Warthog, cpf240,
Heater works great after I removed it and refurbished some of it as it was a frozen bearing case.
I didn't check anything (batteries or alternators), with the multimeter.
I will make a point to do that this weekend coming up.
Also I will check that voltmeter relay under the dash, I just dont know what it looks like so it will be a new find for me.
What I meant by "fine" is that I have no issues cranking the engine, (Batteries appear to be original), engine will start, (after more cranks and a few too many hickups before it is started), and it idles runs great.
Its been this way for 4 years.
These 3 gripes that I listed in the last post actually do not really affect the truck after its started but its there and should be dealt with.
By the way, that slow to kick in or hickup starting up is probably due to that fuel pressure switch which I have and will replace in the spring time.
Your thoughts,

 

[Warthog]

Okay. The heater fuse controls the heater, GEN1 light, 4x4 light and the Oil pressure light. That is why I asked about the heater.

Power to the the GEN1, 4x4 and Oil lights share the same power connector on the printed circuit board on the instrument cluster. The issue could be as simple as a loose connection.



Have you ever removed the instrument cluster and cleaned it? After 30 years it may need cleaning. If you do make sure you disconnect your batteries first.

Make sure you visit the CUCV Helpful Threads sticky. It has links to many of the common issues you will have with your truck. Also download the free technical manuals for your truck. The wiring diagrams are included in the appendix.

 

[cpf240]

Check the helpful threads sticky in the CUCV forum, as the under-dash relays are clearly shown there.

As for the fuel pressure switch, it is not needed unless you plan on using the STE/ICE diagnostic port at the bottom of the dash. It does leak sometimes though, and can be a source of air in the fuel system. Some SS members have removed it and plugged the hole, others have replaced it. I think you can get a new o-ring for it as well.

 

[addinquir]

Thank you Warthog!
This I will do and then give you an update.
Thanks for the cluster photo.

 

[addinquir]

Thanks cpf240,
Will do on the sticky notes.
I actually have a STE/ICE diagnostic box which I purchases many years ago to use on the M1008 and my 72 duce.
I just never hooked it up yet.
Thanks a bunch and I will post my findi gs after this weekend when I get back to it.