Why am I getting 22-30 volts?

Charging, starting, lighting, gauges, HVAC

Moderators: FORDification, Thunderfoot

User avatar
DuckRyder
Moderator
Moderator
Posts: 4893
Joined: Mon Jul 19, 2004 3:04 pm
Location: Scruffy City
Contact:

Re: Why am I getting 22-30 volts?

Post by DuckRyder »

3G are internally regulated....

I don't think the truck should quit when you disconnect the regulator... Dive into the wiring charts...
Robert
1972 F100 Ranger XLT (445/C6/9” 3.50 Truetrac)

"An unarmed man can only flee from evil, and evil is not overcome by fleeing from it." -- Jeff Cooper
User avatar
Ranchero50
Moderator
Moderator
Posts: 5799
Joined: Wed Nov 08, 2006 7:02 pm
Location: Maryland, Hagerstown
Contact:

Re: Why am I getting 22-30 volts?

Post by Ranchero50 »

OK, so the alternator runs away when not being fed to the battery? I haven't dealt with the regulator circuit in a long time so I forget which wire the regulator is sensing off of. I know it's different between a amp gauge and a warning light instrument cluster.
'70 F-350 CS Cummins 6BT 10klb truck 64k mile Bahama Blue

Contact me for CNC Dome Lamp Bezels and Ash Tray pulls.
User avatar
BobbyFord
100% FORDified!
100% FORDified!
Posts: 5342
Joined: Sun Feb 04, 2007 9:52 am
Location: Chatsworth, California

Re: Why am I getting 22-30 volts?

Post by BobbyFord »

This is why I suggested a 3G swap. It seems a lot easier to just rewire a new charging system. Junkyard parts would be inexpensive. Sounds like some severe wiring issues especially if some of the loom is melted together.
GregoYatzee
New Member
New Member
Posts: 23
Joined: Wed Sep 28, 2016 10:26 am

Re: Why am I getting 22-30 volts?

Post by GregoYatzee »

I have known good components, would it be sufficient to just rewire what I have? I don't need the more powerful alternator. If so, should I go with replacing wiring as it is? The ribbon wiring to the ammeter is fried, I don't care if I have it... I don't even have a working gas gauge. I have wondered about rewiring it using the other wiring schematics. Basically switch from the ammeter to the warning light wiring. I likely won't even add a light.

btw moderator, one of the links in the sticky thread on 3g is dead. The info isn't there.
User avatar
DuckRyder
Moderator
Moderator
Posts: 4893
Joined: Mon Jul 19, 2004 3:04 pm
Location: Scruffy City
Contact:

Re: Why am I getting 22-30 volts?

Post by DuckRyder »

GregoYatzee wrote:...The ribbon wiring to the ammeter is fried, I don't care if I have it...
Define "fried"

From my experience (admittedly not on an old Ford truck) bad wring to an ammeter can definitely cause issues in the charging system.
Robert
1972 F100 Ranger XLT (445/C6/9” 3.50 Truetrac)

"An unarmed man can only flee from evil, and evil is not overcome by fleeing from it." -- Jeff Cooper
User avatar
Ranchero50
Moderator
Moderator
Posts: 5799
Joined: Wed Nov 08, 2006 7:02 pm
Location: Maryland, Hagerstown
Contact:

Re: Why am I getting 22-30 volts?

Post by Ranchero50 »

GregoYatzee wrote:I have known good components, would it be sufficient to just rewire what I have? I don't need the more powerful alternator. If so, should I go with replacing wiring as it is? The ribbon wiring to the ammeter is fried, I don't care if I have it... I don't even have a working gas gauge. I have wondered about rewiring it using the other wiring schematics. Basically switch from the ammeter to the warning light wiring. I likely won't even add a light.
Seriously, the light and meter are part of the circuit that makes the regulator work correctly. You really need to unravel the dash and fender wiring, find the other melted sections and repair them.

Image
'70 F-350 CS Cummins 6BT 10klb truck 64k mile Bahama Blue

Contact me for CNC Dome Lamp Bezels and Ash Tray pulls.
GregoYatzee
New Member
New Member
Posts: 23
Joined: Wed Sep 28, 2016 10:26 am

Re: Why am I getting 22-30 volts?

Post by GregoYatzee »

DuckRyder wrote:
GregoYatzee wrote:...The ribbon wiring to the ammeter is fried, I don't care if I have it...
Define "fried"

From my experience (admittedly not on an old Ford truck) bad wring to an ammeter can definitely cause issues in the charging system.

I wondered if the ammeter being disconnected would affect things. I wired it in, sitting on a piece of paper for insulation... almost caught the paper on fire. Here is a pic of the ribbon...

Would not let me upload pic, so here is link to pic on google...
https://goo.gl/photos/GAciAJRmeAyszTHp8
User avatar
Ranchero50
Moderator
Moderator
Posts: 5799
Joined: Wed Nov 08, 2006 7:02 pm
Location: Maryland, Hagerstown
Contact:

Re: Why am I getting 22-30 volts?

Post by Ranchero50 »

You are looking at the results of a direct short from the solenoid through the ammeter to ground. Both side of the ammeter end up on the solenoid so if you are getting a short to ground you have issues with the wiring. Look at this pic in a larger format and finger trace everything to make sure it's connected correctly.

http://graph.darren-criss.org/2016/02/1 ... 724c5b.jpg

You kept saying the ground from the alternator. I don't remember there being one. Post some pics of your alternator and voltage regulator connections. Something stupid happened and we'll figure it out.
'70 F-350 CS Cummins 6BT 10klb truck 64k mile Bahama Blue

Contact me for CNC Dome Lamp Bezels and Ash Tray pulls.
GregoYatzee
New Member
New Member
Posts: 23
Joined: Wed Sep 28, 2016 10:26 am

Re: Why am I getting 22-30 volts?

Post by GregoYatzee »

Ranchero50 wrote:
GregoYatzee wrote:I have known good components, would it be sufficient to just rewire what I have? I don't need the more powerful alternator. If so, should I go with replacing wiring as it is? The ribbon wiring to the ammeter is fried, I don't care if I have it... I don't even have a working gas gauge. I have wondered about rewiring it using the other wiring schematics. Basically switch from the ammeter to the warning light wiring. I likely won't even add a light.
Seriously, the light and meter are part of the circuit that makes the regulator work correctly. You really need to unravel the dash and fender wiring, find the other melted sections and repair them.

Image

I have opened almost all the wiring, Only bad stuff I found was coming off alternator. Replaced ground and am suspect of wiring coming from battery terminal @ alternator and also ribbon on dash. My plan is to direct wire the ammeter, bypassing the ribbon.Thanks for the pic, I hadn't seen that one, helps. With that info, I'm gonna work to replace wires and leave system as is.
GregoYatzee
New Member
New Member
Posts: 23
Joined: Wed Sep 28, 2016 10:26 am

Re: Why am I getting 22-30 volts?

Post by GregoYatzee »

Ranchero50 wrote:You are looking at the results of a direct short from the solenoid through the ammeter to ground. Both side of the ammeter end up on the solenoid so if you are getting a short to ground you have issues with the wiring. Look at this pic in a larger format and finger trace everything to make sure it's connected correctly.

http://graph.darren-criss.org/2016/02/1 ... 724c5b.jpg

You kept saying the ground from the alternator. I don't remember there being one. Post some pics of your alternator and voltage regulator connections. Something stupid happened and we'll figure it out.

The ground wire from alt ground terminal to the base of voltage regulator.
User avatar
Ranchero50
Moderator
Moderator
Posts: 5799
Joined: Wed Nov 08, 2006 7:02 pm
Location: Maryland, Hagerstown
Contact:

Re: Why am I getting 22-30 volts?

Post by Ranchero50 »

Welp, then you'll need to take an ohm meter and start measuring from the charging circuit wires to ground with the battery disconnected. I feel that somewhere you have a wire shorting to ground. If you don't find a direct short or low ohm reading then we'll be one less thing to look for.
'70 F-350 CS Cummins 6BT 10klb truck 64k mile Bahama Blue

Contact me for CNC Dome Lamp Bezels and Ash Tray pulls.
GregoYatzee
New Member
New Member
Posts: 23
Joined: Wed Sep 28, 2016 10:26 am

Re: Why am I getting 22-30 volts?

Post by GregoYatzee »

Today, I found and replaced a bad plug. No fix... I checked every wire in the charging system and nothing... The starter is shorted to ground, though. I never thought to look at it as it has always and even still cranked every time I try it. I will repair or replace it and go from there.
User avatar
Ranchero50
Moderator
Moderator
Posts: 5799
Joined: Wed Nov 08, 2006 7:02 pm
Location: Maryland, Hagerstown
Contact:

Re: Why am I getting 22-30 volts?

Post by Ranchero50 »

The Bendix coil is most likely what you are reading. It should be really low until the Bendix meshes the starter gears and then it'll open allowing the current to go through the starter motor. Only read the resistance on the battery side of the solenoid.
'70 F-350 CS Cummins 6BT 10klb truck 64k mile Bahama Blue

Contact me for CNC Dome Lamp Bezels and Ash Tray pulls.
GregoYatzee
New Member
New Member
Posts: 23
Joined: Wed Sep 28, 2016 10:26 am

Re: Why am I getting 22-30 volts?

Post by GregoYatzee »

Never found any short til I replaced the wire from alternator battery terminal. This led me to the dash. Then to the light wiring. I unplugged lighting at inside firewall and short was gone from entire dash area. Started tracing outside... First, the “dual brake warning switch” tests continuity to ground, both wires. Not sure where to go with this. Left unplugged for remainder of testing. Tested every light bulb, shorted... Wiring feeding bulbs, good. Bright and dim terminals on headlight bulbs had continuity, turn marker tested continuity between two wires, rear lights...same. My next planned step will be to disconnect all lights and connect everything else and see what happens...

After reading this thread, viewtopic.php?t=68376 I will just leave switch unplugged for testing. I'll worry about warning indicators after I get the thing working. I am trying so hard not to give up on this truck. I really appreciate the help you guys have given.
User avatar
Ranchero50
Moderator
Moderator
Posts: 5799
Joined: Wed Nov 08, 2006 7:02 pm
Location: Maryland, Hagerstown
Contact:

Re: Why am I getting 22-30 volts?

Post by Ranchero50 »

Lamps are small filaments of wire so they glow when current goes through them, thus they will read low resistance (couple ohms). I honestly feel that we may be going in the wrong direction (this would be so simpler if it was at my house). Need to focus on what's happening. I did find my fairlane manual in the attic and will take a look at it tonight. The charging circuit is broken down in it better than the truck spaghetti diagrams.
'70 F-350 CS Cummins 6BT 10klb truck 64k mile Bahama Blue

Contact me for CNC Dome Lamp Bezels and Ash Tray pulls.
Post Reply