Red Wire.

Team Dougherty

Original poster
Member
May 22, 2012
117
I know what it is for and where it connects to.:biggrin:

My question is; Is it regulated or just 12 volts all the time? If I connect it to the fuse block and run a wire from my trailer plug to my boat battery will it charge it and then stop or will it just continue to feed it current and over charge?
 

McGMT

Member
Jun 17, 2012
621
Team Dougherty said:
I know what it is for and where it connects to.:biggrin:

My question is; Is it regulated or just 12 volts all the time? If I connect it to the fuse block and run a wire from my trailer plug to my boat battery will it charge it and then stop or will it just continue to feed it current and over charge?

That goes to the brake controller wiring. It doesn't power any wire at the trailer plug...
 

BRomanJr

Member
Dec 9, 2011
371
Team Dougherty said:
I know what it is for and where it connects to.:biggrin:

My question is; Is it regulated or just 12 volts all the time? If I connect it to the fuse block and run a wire from my trailer plug to my boat battery will it charge it and then stop or will it just continue to feed it current and over charge?

When the red wire at the front fuse block is connected to the post it has regulated system voltage at all times. It is the same as hooking directly to the battery but has a fuse and runs all the way to the trailer connector. If your vehicle battery and charging system are working properly the vehicle and trailer batteries will not be overcharged while running or driving.
 

Team Dougherty

Original poster
Member
May 22, 2012
117
BRomanJr said:
When the red wire at the front fuse block is connected to the post it has regulated system voltage at all times. It is the same as hooking directly to the battery but has a fuse and runs all the way to the trailer connector. If your vehicle battery and charging system are working properly the vehicle and trailer batteries will not be overcharged while running or driving.

awesome. I will make the appropriate connector and connect it to my boat trolling motor battery to get the charge started on my way home from the river.

something like this http://www.stayncharge.com/proddetail.php?prod=SNC-7prongplug
 

Wooluf1952

Member
Nov 20, 2011
2,663
Milwaukee, Wisconsin
BRomanJr said:
When the red wire at the front fuse block is connected to the post it has regulated system voltage at all times. It is the same as hooking directly to the battery but has a fuse and runs all the way to the trailer connector. If your vehicle battery and charging system are working properly the vehicle and trailer batteries will not be overcharged while running or driving.

It will, however, continue to charge the trailer battery even with the key OFF, and can drain the truck battery causing a no start condition.
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
The GM designers did some insane things, but leaving this ring lug OFF the nearby stud actually has some debatable purpose.

1) If the red wire is not powered up, the trailer owner has to PURPOSEFULLY install it with an M6 nut, and they might actually think about the issues of a constant-on wire allowing the trailer to drain the starting battery. The best way to do this is to use a high current relay to remove the connection when the ignition is off.

2) A constant-on wire in the trailer connector might get corroded and drain the battery for some non-trailer-towing owner.

It also serves as a constant source of new members who google for "trailblazer red wire" and find us or the OS. :wink:
 

Team Dougherty

Original poster
Member
May 22, 2012
117
the roadie said:
The GM designers did some insane things, but leaving this ring lug OFF the nearby stud actually has some debatable purpose.

1) If the red wire is not powered up, the trailer owner has to PURPOSEFULLY install it with an M6 nut, and they might actually think about the issues of a constant-on wire allowing the trailer to drain the starting battery. The best way to do this is to use a high current relay to remove the connection when the ignition is off.

2) A constant-on wire in the trailer connector might get corroded and drain the battery for some non-trailer-towing owner.

It also serves as a constant source of new members who google for "trailblazer red wire" and find us or the OS. :wink:

My plan was to use a relay or some other "smart" circuit to prevent battery discharge.
 
Feb 24, 2012
133
Any good RV shop should be able to sell you an "isolater" basically an automated switch that turns on over 12.5V or so and shuts the circuit off under that, so it will only connect while the charging system is working. I was trying to look one up just now and a little research shows them to be of questionable reliability, so some people use a relay instead, activating the circuit only when the ignition is on. I'm going to wire my truck that way - by relay.
 

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