Charging issue 1986 m1009

[Ammo1984]

I followed the wiki on checking my ds alt and I found something weird.
25.4v, not 12 when the truck is not running.
I also checked the top of the glow plug relay and have the same voltage.
I followed the battery wiring diagram I found here and that is correct.
No alt lights for fen 1 or gen 2.

Please help, I am lost here.

Ammo1984

 

[Skinny]

I followed the wiki on checking my ds alt and I found something weird.
25.4v, not 12 when the truck is not running.
I also checked the top of the glow plug relay and have the same voltage.
I followed the battery wiring diagram I found here and that is correct.
No alt lights for fen 1 or gen 2.

Please help, I am lost here.

Ammo1984

Wouldn't two fully charged 12v batteries give you 12.8v x2 = 25.6v which is close to what you have

 

[Ammo1984]

Yes it would.
If the alts were working I should have 14 at Dr alt and 29 at pass side alt.
This 25v at ds alt running or not is confusing me

 

[WWRD99]

I followed the wiki on checking my ds alt and I found something weird.
25.4v, not 12 when the truck is not running.
I also checked the top of the glow plug relay and have the same voltage.
I followed the battery wiring diagram I found here and that is correct.
No alt lights for fen 1 or gen 2.

Please help, I am lost here.

Ammo1984

You say no alt lights for gen one or 2...do the lights come on with the key on and engine not running?

 

[Ammo1984]

You say no alt lights for gen one or 2...do the lights come on with the key on and engine not running?

No light when key is on and not running

 

[WWRD99]

No light when key is on and not running

There ya go!! Gotta have both of those lit with the key on not running and sometimes both will be lit when turning over or sometimes 1 will go out but 2 stay on...with really good batteries and solid alternators that's what mine do...the power to the alternators regulator goes through those bulbs so if they're burned out or leds or fuse or something not plugged in you won't make power...this is stock version though if that's what you have...look up in the stickies on a post that goes through all the testing...there's also wiring diagrams here too...sounds like you'll find it quick.

Sent from my SM-G975U using Tapatalk

 

[MarcusOReallyus]

I followed the wiki on checking my ds alt and I found something weird.
25.4v, not 12 when the truck is not running.

Where are you connecting the black lead when you take that measurement? Where are you connecting the red lead?

I also checked the top of the glow plug relay and have the same voltage.

That is normal voltage for the top of the GP relay when the GPs are not turned on. (in a stock truck with the GP resistor intact.)

When the relay is triggered and the GPs are on (glowing) you should see about half that.

 

[Ammo1984]

Found a wiring issue.
With 24v going to the dash I had to replace all the lights.
The 12v alt is now working but the 24v is not.
The relay is working but no power to excite the alt.

 

[MarcusOReallyus]

Why do you think you have 24v at the dash? Where did you measure that?



The "GEN" lights are part of the exciter circuit, so if they were blown, there's your problem.

But check your fusible links. Some on the 24v buss bar, some on the 12v diamond near the GP relay.

 

[Ammo1984]

Thank you for the info.
The bulbs are good.
Looking for the fusible links.

 

[user65]

Found a wiring issue.
With 24v going to the dash I had to replace all the lights.
The 12v alt is now working but the 24v is not.
The relay is working but no power to excite the alt.

Make sure there is a 194 bulb in the dash for gen 2 not 168.

 

[MarcusOReallyus]

Looking for the fusible links.

This might help a bit:

Fusible Links - 101

With all the electrical problems people are having with the CUCV starter and Glowplug systems lately, I thought I would post some info. -------------------------------------------------------------------------------------- This is from www.Whiteproducts.com. It is located in their FAQ section...

www.steelsoldiers.com

 

[Ammo1984]

FIXED.

The 194 light bulb did the trick.

Thank you everyone for your help.