2.9 short....

[2.9v6forlife]

Good morning I have a 1988 with the 2.9 and my voltage regulator keeps popping as soon as I put a new one on I did find the black and orange wire that runs from the starter solenoid around through the core support into the cab I found a connection burnt up does anyone know where that black and orange wire goes to

 

[RonD]

Welcome to TRS

Black/orange stripe wire should not run into the Cab

Do you have an alternator with built in voltage regulator or an external voltage regulator?


The Black/orange wire should run from Alternator's B+ terminal, larger terminal on the back, to the Starter Relay(solenoid) but it will have a Fusible link(inline fuse) at the Starter relay end.

If you have an external regulator then on the dash you will have an AMP gauge, charge+/discharge-
AMP gauge needs a SHUNT on the Black/orange wire, 2 smaller wires(yellow and red) that run to the AMP gauge from the Black/orange wire
Drawing here: https://therangerstation.com/tech_library/EDiagrams/files/diagram_charging_1983to1985_1.JPG

Top center


If you have an internal regulator you will have a voltage gauge in the dash, which is not connected to alternator.


It was very common for people to change alternators to internal regulator models, they last longer and produce better power than the older external regulator models
So the wiring may have been converted to use the newer alternator style.


Lets us know what you have, internal or external regulator?

 

[2.9v6forlife]

I have a internal regulator and wire goes from starte solenoid to around the front to fire wall then ties in with yellow with white line also black and orange and two black wire alternator black orange wire from alternator is on own harness goes behind motor ties back in by firewall roughly same area

 

[2.9v6forlife]

I am not sure on how to post a photo

There Is no gauge in the cab just a warning light I have negative cable disconnected with a test light hooked in between cable and terminal it lights up if I touch any metal on the truck light will light up if I disconnect orange and black just before it splits off I lose my shorting problem but I have no power to anything I have pulled all fuses to see if I could narrow it down with no luck

 

[RonD]

Then you will use this wiring diagram as the baseline: https://therangerstation.com/tech_library/EDiagrams/files/Diagram_charging_1991_2.JPG
This drawing uses 2 wires on B+ and a fuse box, yours may only have the one Black/orange wire and use Fusible links instead of fuse box fuses


The alternator will have 3 wires connected, and a white jumper
1. Black/orange on B+(stud with nut), goes to Battery Post on Starter Relay(solenoid)

2. Yellow/white on 3 wire connector, <<< this CAN BE spliced to the Black/Orange wire, goes to Battery Post on Starter Relay

3. Light Green wire on 3 wire connector, <<< this wire DOES run into the cab it is connected to Battery(Charge) light in the dash, this is the ON/OFF switch for alternator

1. and 2. should have fusible links attached, a Fusible link is a short wire that is slightly smaller gauge than Black/orange wire, they look like this: https://www.onallcylinders.com/wp-content/uploads/2017/11/09/Pico-Fusable-Link.jpg

They come in different sizes(gauges) and colors for different AMP ratings, they are used as a less expensive alternative to an in line SLOW BLOW fuse.


At the alternator unplug the 3 wire connector
Test for 12volts at B+ wire, should be connected, and you should have 12v, it should have battery voltage exactly, so test battery first, if its 12.5v then thats what you should see at B+

Then test unplugged Yellow/white wire, should also be Battery voltage exactly

Then test green wire, Key OFF, should be 0 volts
Then turn key on, should now be battery volts

It this happens then alternator wiring is OK short is elsewhere

 

[2.9v6forlife]

That all checked out what I did notice is I lose my short when I turn my key off but if I turn my head lights my short comes back weather the key is on or off

 

[2.9v6forlife]

All tested fine If I turn key to off Position I lose my short but if I turn on my headlights my short returns doesn’t matter if my keys on or in the off position I don’t know how that is all tied in together but starting to get frustrated

 

[RonD]

Headlights and brake lights have full time connection to battery, these do not go thru ignition switch(key on/off)

In 1988 head light switch power could have connection on the starter relay post(via fusible link) or in the engine fuse box

Brake light fuse will be in cab fuse panel

 

[2.9v6forlife]

I don’t know what to do I feel like I have narrowed it down to yellow and white stripe and yellow wire traced them all the way to fire wall no bad spots

 

[2.9v6forlife]

Now if I have key off and just turn headlights on and pull number 4 fuse exterior lamps instrument illumination and can get it to stop shorting out I pulled cluster and in plugged it not the problem

 

[2.9v6forlife]

I pulled instrument panel not the problem

 

[bobbywalter]

the black and orange is cab power. i assume the connection you referred to was a single spade 10 gauge?

the split off to the yellows going to main power the ignition switch i dont remember what side of the fuse block they were on.


it being burnt up is a key indicator of high resistance or draw.


i suspect the headlight switch is also burnt up and it downline/backsided into the column multifunction wiring when something was being used....and maybe some melty bonding wiring orgy of doom going on in there....this may or may have not started with a huge corrosion issue if its dropping water on the block...

seen it before...usually flood vehicles though.

 

[RonD]

Could be main light switch then
Dimmer module inside it, i.e. you rotate knob to dim or brighten instrument cluster lights

The solid Yellow wire is the main power to the cab fuse panel and ignition switch.

The yellow/white stripe should not go into the cab, it is just for voltage regulator on alternator, and runs to battery post on starter relay, it may be spliced to Black/orange wire.
If it runs into cab maybe previous owner needed full time power for something?


There is another yellow/white stripe wire that runs from instrument cluster to the gas tank, its for fuel level

 

[bobbywalter]

yeah...the headlight switch is probably trashed and needs a whole new piggy ect.



i generally tied into the 10-12 gauge wires on conversions to run the stand alone eec4 setups from the ignition switch. there are a few connectors for them along the way and they can get resistive...once there is heat damage your fawked....if it was a straight wire right from the battery then it would probably never be an issue.


everything will be fine....blower on med... headlights on... and then it starts raining and you need the wipers on high and shit goes crazy once you hit the brakelights... ect..

 

[bobbywalter]

which stresses grounds....so i ground...or add grounds because these rust and corrode...