I just bought a felling dump trailer and the battery kept dying on it. it is supposed to get charged from the truck, however gm has decided that they did not want to be held responsible for people burning up the wiring on the system on the truck so they make the customers wire up the sytem to the fuse box and do all the work. has anyone done this process themselves yet, and how long does it take? not really looking forward to taking the cover on the fuse box off because im not really an electric guy. if anyone has done this please chime in.

Pretty easy.

Go here: http://www.dieselplace.com/forum/showpost.php?p=2557997&postcount=1

HTH

http://www.dieselplace.com/forum/showthread.php?t=159743&highlight=brake+controller
Ignore this, I see you just want charge not brake controller.

I think he is wanting to hook up the 12V feed to the 7-way trailer connector, not hook up a brake controller...

Well the first thing to do is to look around and see what other companies have done and copy that.This is the first step in what you are doing.Now If you have a battery charger at home always charge the trailer battery before you put it back into the trailer. Get a multimeter of your price range they are wonderful for measuring. I think that your truck is one of the new ones that have the posts that I have been hearing about. Being creative if there is room to add an ( Extention nut this is a longer nut they come in sizes from 1/8" to 3/4" with lengths of an inch to 13/4"s long so if they aren't metric then I suspect that 5/16" is the size so and overall cut length of ??? 5/8" I would weld a tab 1/8" x1/2"x1/2" with a 1/4" drilled and tapped). If you do something like this get some splicing tape and put some R-33 tape over top of it! There probably isn't room to do this so this will go out the window?

I would put on the larger fuse holder these are good for ??60 amps or so weatherproof if available? Wire size # 10 or larger # 8 would be very good. Do get the two wire and a two wire plugin unless going throught the 7 pin plug? Ground the white on a ground for the battery or next to it with a 1/4" size machine screw. I use the uninsulated terminals and solder them and use RTV under the heat shrink to keep the water out of the splice. If you like this or need more info I am home usually on the weekends. Hope this makes sence??? :D

Ok. The truck 7 way plug is not wired with power to the batteries from the factory. The wire for the battery power is located taped to the wiring loom under the brake booster area. It should be about two feet long if I remember right.

The fuse was installed for the circuit you just have to install the pigtail wire to the stud in the fuse box. This will send power to the 7way plug to charge the batteries. You will need a nut and a lock washer as well. Do a search on LMM TRAILER WIRING and you should find helpful pictures as well :)

thanks for the response useful info. metalhead you are correct it is taped unders the brake booster area. it was on the gm website that my mechanic uses, very simple to do. im doing it on saturday

the GM wesite

Is this for like a power take-off sort of thing like to power up an electrical plug in your trailer from the truck battery? I thought when you hook up the trailer plug into the truck it will charge the battery in the trailer automatically, because until I left the lights on, the battery has always been fully charged so it obviously wouldn't have lasted that long without it being charged somehow?

im talking about my dump trailer wich has a battery in it to lift the piston. it doesn't have an alternator so you get the power to charge the battery through the truck. same thing as what you would need for an rv.

however gm has decided that they did not want to be held responsible for people burning up the wiring on the system on the truck so they make the customers wire up the sytem to the fuse box and do all the work.

Since someone already posted the directions, I'd like to help you see things like the General does.

The presence of 12v all the time at the trailer plug results in a higher number of warranty claims and failures. Continuous 12v there WILL encourage premature corrosion of the terminals once exposed to moisture (the real world), and can also result in draining of the truck battery. So, the end result is corroded harness(es) and plug socket(s) under warranty ($$$) and/ or roadside assistance calls to jumpstart the truck.

It is amazing how many people don't realize that using their camper 12v all night long WILL drain the truck battery. And, having a fleet of trucks with 7 pin plugs, it is amazing how short the plug and harness life can be in the "salt belt". I don't even use the charge circuit and I still get "rot out" of the electric brake wire and terminal as 12v is always present there.

I'm not saying you shouldn't be disappointed, but rather that you should appreciate the fact the a simple hand tool and fuse are all that's required, and that you do NOT have to string a 12v charging wire all the way to the back of the truck.

I did not care for the constant 12 volt, and always having to disconnect the 7 way plug.
I solved the problem by installing a H.D. 30 amp relay on the fender well next to the fuse box ,connected the 12 volt trailer charge power to to the relay for assessories and used the constant 12 volt term for the 12 volt power and the switch on in the relay only on when the ignition is on.
No more draining batt or disconnecting 7 way plug.
The relays you buy at Autozone or Checker has the wiring diagram on the package.
ground,constant 12 volt power,12 volt to switch (that you can use a smaller wire) from ign power,then the assessories you want to power there is usually 2 term for this one.
This one you only use one unless you have something else you want to power with ign on.
Mine I used both terminals one for the trailer charge line the other my airbags controller in the cab.

If you live in the salt belt, you can pretty well do away with the corrosion if you coat the plug with dielectric grease. I make sure mine is well greased during the winter months. Also I had a couple of plugs replaced from corrosion on the inside of the plug, so I now take the harness off the back of the trailer plug and put the dielectric grease to it once a year.
For those who are not familar it's available at any truck parts store, and NAPA


Bill

If you live in the salt belt, you can pretty well do away with the corrosion if you coat the plug with dielectric grease. I make sure mine is well greased during the winter months. Also I had a couple of plugs replaced from corrosion on the inside of the plug, so I now take the harness off the back of the trailer plug and put the dielectric grease to it once a year.
For those who are not familar it's available at any truck parts store, and NAPA


Bill
Having run dielectric grease from napa (clear) and now using Trucklite dielectric grease (brownish), I can tell you that either will prolong the duration before failure, BUT they'll stll rot out within 2 years, in my fleet.

Moved to electrical.

I did not care for the constant 12 volt, and always having to disconnect the 7 way plug.
I solved the problem by installing a H.D. 30 amp relay on the fender well next to the fuse box ,connected the 12 volt trailer charge power to to the relay for assessories and used the constant 12 volt term for the 12 volt power and the switch on in the relay only on when the ignition is on.
No more draining batt or disconnecting 7 way plug.
The relays you buy at Autozone or Checker has the wiring diagram on the package.
ground,constant 12 volt power,12 volt to switch (that you can use a smaller wire) from ign power,then the assessories you want to power there is usually 2 term for this one.
This one you only use one unless you have something else you want to power with ign on.
Mine I used both terminals one for the trailer charge line the other my airbags controller in the cab.

Very good idea! I wondered why my trailer batter was dead and I didn't have any lights in there while it was connected to the truck. My past GM trucks would always power it. I think I'm going to go this route. Thanks for the tip!

i put a breaker inbetween instead of a puting a fuse, and have to take off the breaker box cover. im not good with electrical and didn't wan't to short anything out. check out pics in my garage.

Is this for like a power take-off sort of thing like to power up an electrical plug in your trailer from the truck battery? I thought when you hook up the trailer plug into the truck it will charge the battery in the trailer automatically, because until I left the lights on, the battery has always been fully charged so it obviously wouldn't have lasted that long without it being charged somehow?

Some trailers have battery wire tied into park lights to power trailer lights, acc, etc.

Since someone already posted the directions, I'd like to help you see things like the General does.

The presence of 12v all the time at the trailer plug results in a higher number of warranty claims and failures. Continuous 12v there WILL encourage premature corrosion of the terminals once exposed to moisture (the real world), and can also result in draining of the truck battery. So, the end result is corroded harness(es) and plug socket(s) under warranty ($$$) and/ or roadside assistance calls to jumpstart the truck.

It is amazing how many people don't realize that using their camper 12v all night long WILL drain the truck battery. And, having a fleet of trucks with 7 pin plugs, it is amazing how short the plug and harness life can be in the "salt belt". I don't even use the charge circuit and I still get "rot out" of the electric brake wire and terminal as 12v is always present there.

I'm not saying you shouldn't be disappointed, but rather that you should appreciate the fact the a simple hand tool and fuse are all that's required, and that you do NOT have to string a 12v charging wire all the way to the back of the truck.

Nice to see a different opinion.

So how much current can you pull from this battery charge circuit? I believe it is pin 4 on the connector. I am trying to run a small 12 V water pump that can draw up to 10 Amps. I believe the fuse you get when you connect GM harness is a 30 Amp. I can see 13. 9 Volts on the pin but I don't seem to get any current to run the pump. Any ideas?

You may have a bad ground. Use a test light and test the connections.:)