mtc maintence and repairs on his new ‘85

[FJ_Hooligan]

Okay, I'll try to be more complete.

The ignition connector has 3 wires.  The red wire is the 12 volt source from the battery.  It comes to this connector, passes through to the actual physical ignition switch which when turned to the ON position connects this 12 volt source to BOTH the brown and blue wires, giving them 12 volts. 

The blue wire originally ran driectly to the tail lights and nowhere else.  In the PARK position of the ignition switch, the red wire is connected to the blue wire to turn the tail lights on.

The brown wire (which has been cut and now has the short white jumper wire) provides 12 volts to the main harness and branches out through the fuse block to provide 12 volt power to other circuits.  The main power wires on the FJ are brown and red with white stripe.  If you see a wire with these colors, it is a switched 12 volts.

One of the branches of this brown power circuit is the brown wire going to the alternator.  This wire is part of the main harness and originally ended in a 2-wire connector behind the sidecover (the red and brown wire connector).  This is the connector that can overheat and melt.  I'll bet this happened to the PO and he cut this 2-wire connector out of the circuit.  The original brown wire to the alternator must have been melted or damaged enough that it was unuseable so the PO ran a separate wire (the white wire) back to the ignition connector and combined it with the tail light wire (at the vampire connector).

If you root around in the sidecover, I'll be you can find the original brown wire (with a cutoff end).  If you ohm it, it's probably a short to ground or an open due it being damaged when the connector overheated. 

Again, other than the vampire splice, it's all good.

[mtc]

Okay, I'll try to be more complete.

The ignition connector has 3 wires.  The red wire is the 12 volt source from the battery.  It comes to this connector, passes through to the actual physical ignition switch which when turned to the ON position connects this 12 volt source to BOTH the brown and blue wires, giving them 12 volts.  

The blue wire originally ran driectly to the tail lights and nowhere else.  In the PARK position of the ignition switch, the red wire is connected to the blue wire to turn the tail lights on.

The brown wire (which has been cut and now has the short white jumper wire) provides 12 volts to the main harness and branches out through the fuse block to provide 12 volt power to other circuits.  The main power wires on the FJ are brown and red with white stripe.  If you see a wire with these colors, it is a switched 12 volts.

One of the branches of this brown power circuit is the brown wire going to the alternator.  This wire is part of the main harness and originally ended in a 2-wire connector behind the sidecover (the red and brown wire connector).  This is the connector that can overheat and melt.  I'll bet this happened to the PO and he cut this 2-wire connector out of the circuit.  The original brown wire to the alternator must have been melted or damaged enough that it was unuseable so the PO ran a separate wire (the white wire) back to the ignition connector and combined it with the tail light wire (at the vampire connector).

If you root around in the sidecover, I'll be you can find the original brown wire (with a cutoff end).  If you ohm it, it's probably a short to ground or an open due it being damaged when the connector overheated.  

Again, other than the vampire splice, it's all good.

again sorry to drag this out for you, you  probably have other things to do, so i appreciate it.

so you are saying the the white wire is the Main Source power wire for the entire bike and does it needs to be switch or Hot all the time?

so this is what puzzles me and sorry to be so obtuse, since the blue wire's sole purpose in life is to supply power to the taillight on the "p" position, and that  it is NOT switch on until the key is on the "P" postilion.

if this is the case

my having replaced the broken factory original ignition switch last week( key won't go in and lock pin won't come out) with a cheap ebay replacement without a "P" position ( i could live without the battery drain potential)

this alone renders the circuit inoperable

so...

why is the white wire even connected to that, should it not be connected to the red on instead?

[FJ_Hooligan]

again sorry to drag this out for you, you  probably have other things to do, so i appreciate it.

so you are saying the the white wire is the Main Source power wire for the entire bike and does it needs to be switch or Hot all the time?

so this is what puzzles me and sorry to be so obtuse, since the blue wire's sole purpose in life is to supply power to the taillight on the "p" position, and that  it is NOT switch on until the key is on the "P" postilion.

if this is the case

my having replaced the broken factory original ignition switch last week( key won't go in and lock pin won't come out) with a cheap ebay replacement without a "P" position ( i could live without the battery drain potential)

this alone renders the circuit inoperable

so...

why is the white wire even connected to that, should it not be connected to the red on instead?

I think I misspoke in an earlier post and confused you.

The red wire is the source of 12 volts.  Connection of the red wire 12 volts is done by the ignition switch.  When ON, the switch gives power to the brown and blue wires of the ignition connector. 

As you now know, the blue wire powers tail lights.  The tail lights need power in ON or PARK mode.  Since you lost the PARK mode with the new switch, it's no big deal.  You don't have that mode but the tail lights still get power from the blue wire.

The brown wire coming out of the ignition connector also gets 12 volts when the ignition is ON.  This wire powers all the other electronics on the bike.  The short white jumper wire connects the short brown wire out of the connector to the brown wire going into the wire harness.  This provides power to everything needing 12 volts. 

One of the things on the bike that needs to see 12 volts is the alternator.  The alternator output will change depending the state of the battery voltage.  If the battery voltage is below 12 volts then the alternator needs to output more power to keep the battery charged.  If the output is greater than 12 volts then the alternator can reduce its output.

Thus, the alternator needs to know what the battery voltage is.  It gets this from the long white wire on your bike.  The original wire runs through the wire harness.  However, it was damaged so the PO added the white wire.  Theoretically, this alternator voltage reference could come from any 12 volt circuit on the bike but small wire voltage losses and other electronics on a circuit could corrupt the actual voltage value.  Therefore, the most accurate indication of battery voltage would be from a direct link to the battery itself.  The white wire essentially provides that voltage since it is a dedicated circuit from the red wire at the ignition connector (which IS a direct wire from the battery).

The PO could have vampired off the the brown wire (at ign connector) but instead chose to do it off of the blue.  Same result either way, the alternator is seeing battery voltage courtesy of the white wire spliced into the yellow fused wire which is connected to the brown wire in the sidecover.

Am I using too many words?  I don't know any other way to keep saying the same thing.

[mtc]

again sorry to drag this out for you, you  probably have other things to do, so i appreciate it.

so you are saying the the white wire is the Main Source power wire for the entire bike and does it needs to be switch or Hot all the time?

so this is what puzzles me and sorry to be so obtuse, since the blue wire's sole purpose in life is to supply power to the taillight on the "p" position, and that  it is NOT switch on until the key is on the "P" postilion.

if this is the case

my having replaced the broken factory original ignition switch last week( key won't go in and lock pin won't come out) with a cheap ebay replacement without a "P" position ( i could live without the battery drain potential)

this alone renders the circuit inoperable

so...

why is the white wire even connected to that, should it not be connected to the red on instead?

I think I misspoke in an earlier post and confused you.

The red wire is the source of 12 volts.  Connection of the red wire 12 volts is done by the ignition switch.  When ON, the switch gives power to the brown and blue wires of the ignition connector. 

As you now know, the blue wire powers tail lights.  The tail lights need power in ON or PARK mode.  Since you lost the PARK mode with the new switch, it's no big deal.  You don't have that mode but the tail lights still get power from the blue wire.

The brown wire coming out of the ignition connector also gets 12 volts when the ignition is ON.  This wire powers all the other electronics on the bike.  The short white jumper wire connects the short brown wire out of the connector to the brown wire going into the wire harness.  This provides power to everything needing 12 volts. 

One of the things on the bike that needs to see 12 volts is the alternator.  The alternator output will change depending the state of the battery voltage.  If the battery voltage is below 12 volts then the alternator needs to output more power to keep the battery charged.  If the output is greater than 12 volts then the alternator can reduce its output.

Thus, the alternator needs to know what the battery voltage is.  It gets this from the long white wire on your bike.  The original wire runs through the wire harness.  However, it was damaged so the PO added the white wire.  Theoretically, this alternator voltage reference could come from any 12 volt circuit on the bike but small wire voltage losses and other electronics on a circuit could corrupt the actual voltage value.  Therefore, the most accurate indication of battery voltage would be from a direct link to the battery itself.  The white wire essentially provides that voltage since it is a dedicated circuit from the red wire at the ignition connector (which IS a direct wire from the battery).

The PO could have vampired off the the brown wire (at ign connector) but instead chose to do it off of the blue.  Same result either way, the alternator is seeing battery voltage courtesy of the white wire spliced into the yellow fused wire which is connected to the brown wire in the sidecover.

Am I using too many words?  I don't know any other way to keep saying the same thing.

ahhhh ha..... thanks what a good lesson, your the man!

12v reference to regulate alternator output, from a source least affected by noise

brown / blue immaterial

the PO knew his stuff, i don't

funny thing is leaving nothing to chance requires comprehensive wording.

is this the result ( of the notoriously rumored over-active early fj alternator supplying too many volts, if yes, is there a remedy that is required and is it a non issue?

[FJ_Hooligan]

You got it!

The overcharging issue is usually a bad voltage regulator.  There are several fixes for that.

An inaccurate voltage on the brown wire to the alternator (such as a low voltage caused by parasitic losses) would cause the alternator to overcharge in response.  Certainly could be a contributor.

I suffered the melted connector on my '85 several years back.  Caught it before any damage was done and replaced the blade connectors with quality bullet connectors with clear sealed enclosures so I can monitor for any corrosion. 

Pretty sure the original blades started corroding which caused the resistance to build up which lead to the overheating and melting.  Didn't see it until I randomly pulled the connector apart one day.  The melted part was on the backside of the connector so I never saw it.

[mtc]

You got it!

The overcharging issue is usually a bad voltage regulator.  There are several fixes for that.

An inaccurate voltage on the brown wire to the alternator (such as a low voltage caused by parasitic losses) would cause the alternator to overcharge in response.  Certainly could be a contributor.

I suffered the melted connector on my '85 several years back.  Caught it before any damage was done and replaced the blade connectors with quality bullet connectors with clear sealed enclosures so I can monitor for any corrosion. 

Pretty sure the original blades started corroding which caused the resistance to build up which lead to the overheating and melting.  Didn't see it until I randomly pulled the connector apart one day.  The melted part was on the backside of the connector so I never saw it.

cool thanks very much again!