7-pin connector help

[TJNE]

I pull a 5vr with my 07 Classic, I usually take relitivly short trips however recently I went on a 1200 mile round trip and realized that my battery in my 5vr was dead at the end of a travel day. I then checked the connector and found the pin that is supposed to charge the 5vr was dead. I looked in the owners manual for fuses/relays and with vauge guidence I could not find anything blown/burned out. I checked the block in the dash and under the hood and all seems well, does anyone have any idea where I should look next? The harness seems undamaged, what I can see of it. :confused:

[DmaxMaverick]

Was it charging before, and now it isn't? If it never was (sounds like it), or you don't know, you probably need to install the fuse in the underhood fusebox. They aren't installed at the factory, and very few dealers do it before delivery, and even pro brake installers don't. Not sure about 2007 models, but earlier models included a trailer brake harness and fuse (not installed) with the trailering package. If you didn't receive the harness kit, or didn't take delivery with the trailering package, you'll have to purchase one, or go back to your salesman and demand one. The fuse will be installed in the top row (inboard) in the fusebox. The position has changed a couple times over the year models, but it should be marked on the box lid diagram. If you have a slot with connectors visible, and no fuse, that's it.

[TJNE]

Thanks, I had the wire and controler from my last truck and it had a fuse was with it when I put it in my other truck but never noticed if it charged the other trailer (short trips). That is probably the issue. I don't know if I can find the fuse again, I think it was a large square green one. If I can't find it what size (amp) fuse do I need?

[DmaxMaverick]

50 amp, IIRC.

[TJNE]

I checked the fuse block under the hood and all the spots have fuses in them and they all look good. Any other ideas? Are there any fusable links or relays? Who has a good repair manual I could buy?

What is the little light blue wire at the back of the 7-pin connector that has a cap on it?

[DmaxMaverick]

No fusible links or relays.

The blue wire is normally for the trailer brake circuit, and shouldn't be "little". 12-10ga is normal size. What position is it? Looking at the truck socket from the end the trailer plug connects (cap lifted), the blue/brake should be at the 7 o'clock position (5 o'clock looking at the wire/back end). The 12V charge circuit should be a 10ga black wire at the 11 o'clock position (or 1 o'clock from the back). The 12V charge circuit should have battery voltage at all times. It is not switched or relayed, if wired OEM.

[DmaxMaverick]

........And, for the manual:

www.helminc.com for printed dealer-type service manuals. Expensive, and slow shipping.
www.alldatadiy.com for online manuals (recommended). Much less expensive, with instant access.

[TJNE]

I got it. Below is a info bulliton I found online. The owners manual states on page 605:

Stud #1 Auxillary Power (Single Battery and Diesels Only)/ Dual Battery (TP2) Do Not Install Fuse.

I called the Dealer and they said the didn't know. Thanks for nothing......
What you need to do is follow the directions in ORANGE at the bottom. You will need to look at the silver colored RPO sticker in the glove box for TP2. The way I read it is if you have TP2 and you leave the trailer hooked without the engine running it will drain the batteries. If you don't have TP2 then you won't. If anyone inturprets it different or has better info please correct me as this the best info I have found so far. Hope this helps.:D


Subject:Information on Auxiliary Power Wire at Trailer and Installation of Aftermarket Trailer Brake Controller - Towing, Tow #06-08-45-008A - (09/18/2007)





Models:2007-2008 Cadillac Escalade, Escalade ESV, Escalade EXT
2007-2008 Chevrolet Avalanche, Silverado, Suburban, Tahoe
2007-2008 GMC Sierra, Yukon, Yukon Denali, Yukon XL, Yukon Denali XL



This bulletin is being revised to provide detailed steps for installing an electric trailer brake controller. Please discard Corporate Bulletin Number 06-08-45-008 (Section 08 -- Body and Accessories).

Important: Installation of an electric brake controller and the wiring connections outlined in this bulletin are the responsibility of the dealership or customer. These repairs should never be charged to warranty. If you have any questions, please consult with your District Service Manager.

Some customers may have questions on how to connect an electric trailer brake controller or where the brake controller pigtail harness is located.

Starting with the new 2007 full-size utilities and pickups, there is no longer an electric trailer brake controller pigtail harness.

An aftermarket brake controller will need to be installed/connected to the blunt wires under the left side of the IP for vehicles built without JL1 - Integrated Brake Controller. The following steps should be used to complete the installation.

<LI type=1> Locate the trailer brake control circuits that are looped and taped to the main harness under the instrument panel.
<LI type=1>Pull the trailering wire harness down.

<LI type=1>Match the vehicle harness label circuit functions to the trailer brake controller jumper harness functions. Important: The color or wires to be joined together may not match.


• Dark Blue Wire: switched power from controller to trailer brakes
• Red with Black Stripe: fused vehicle power to electrical brake controller
• Light Blue with White Stripe: Brake switch input to power electric brake controller
• White: ground
• Orange: CHMSL (Center High Mounted Stop Lamp) -- not required with most systems
<LI type=1>After completing the under dash connections to the electric brake controller, open the hood and locate the red wire that is taped to the harness between the underhood electrical center and the driver side front fender. <LI type=1>Break the tape on the red/black wire and pull it toward the front of vehicle. <LI type=1>Remove the lid from the electrical center.
<LI type=1>Place the terminal on the larger of the two studs at the front of the electrical center and secure with an M8 nut. This is circuit #242 to stud #2, to power the aftermarket trailer brake controller. Important: The fuse is already present in the vehicle to power the electrical trailer brake controller system.

AUXILIARY POWER: Circuit #742 for Auxiliary Power at the 7-way trailer connector is no longer connected by the GM Assembly Plant. If the customer desires auxiliary power at the trailer connector location (i.e. refrigeration, battery charger or interior light in the trailer), complete steps 8.1 thru 8.4 to connect circuit #742:
8.1. Locate the red/black wire, looped and taped to the chassis harness, below the brake master cylinder.
8.2. Break the tape and route the wire to the front of the underhood electrical center.
8.3. Place the terminal on the smaller of the two studs on the electrical center and secure with an M6 fastener. This is circuit #742 to stud #1 for auxiliary power to the 7-way trailer connector.
8.4. ONLY for vehicles without RPO TP2 - Auxiliary Battery, install a 40 amp fuse to power the circuit.


Important: For vehicles equipped with RPO TP2 -- Devices powered by this fuse will drain the vehicle battery if left connected with the vehicle not running.

[bashfour]

all dmax,s have a dual battery setup which is different than an auxillary battery, if you connect the wires taped under the master cyl to the terminals at the end of the electrical box you will have power, 1/trailer brakes 1/12v to trailer harness they do not have nuts on them so you will get these.

[MacDR50]

Been away so read this late. For those who like to watch, Etrailer.com provides some video installation instructions for the install that shows the connection mentioned above. Wish GM had included the M6 and M8 nuts ( If I remember correctly) as they are hard to find on a Sunday afternoon. I actually drilled out a NC nut and tapped it 8mm to finish the job.

http://www.etrailer.com/tv-Brake-controller-2009-Chevy-SilveradoF.aspx

[Mark Rinker]

A timely post to have at the top today - I have our boat behind the 3500 SRW and have once again encountered a very frustrating safely interlock that will not allow the boat trailer to back up, unless the truck's backup light function is wired correctly from tow vehicle to trailer. Most aren't...

In the past, each time a new MRE truck shows up on the scene, I run into this problem at the boat ramp in the spring or fall. Very frustrating, sometimes just a fuse is blown or missing, other times the truck's female connector was never wired for the backup lamp function in the first place.

The trailer has a small clear light on the port side, behind the axles that illuminates when in reverse and the safety backup interlock is released.

I guess the idea is to keep the trailer from rolling backwards, unless its hooked to a vehicle that is intentionally in reverse...

[DmaxMaverick]

A timely post to have at the top today - I have our boat behind the 3500 SRW and have once again encountered a very frustrating safely interlock that will not allow the boat trailer to back up, unless the truck's backup light function is wired correctly from tow vehicle to trailer. Most aren't...

In the past, each time a new MRE truck shows up on the scene, I run into this problem at the boat ramp in the spring or fall. Very frustrating, sometimes just a fuse is blown or missing, other times the truck's female connector was never wired for the backup lamp function in the first place.

The trailer has a small clear light on the port side, behind the axles that illuminates when in reverse and the safety backup interlock is released.

I guess the idea is to keep the trailer from rolling backwards, unless its hooked to a vehicle that is intentionally in reverse...

This is unique to large(r) and later boat trailers. Most smaller boats/trailers (family size recreational, bass, and ski) don't have trailer axle brakes. The purpose of the system is to aid in boat launch/recovery, and help prevent launching the tow vehicle with the boat. Imagine jumping out of your truck, having to race after it as it heads down the ramp without you (or runs over you/others). I've seen it many times, and it makes for great "funniest video moments", unless it's you (wasn't me, knock wood). If a truck has a manual tranny, the E-brake is relied upon for holding at the ramp. Most E-brakes aren't as effective for holding reverse compared to forward (such as on a boat ramp), and they don't improve when wet (many times, become nearly completely ineffective). Ideally, the engine should be shut off with the tranny in gear. Unfortunately, many vehicles won't restart if the tailpipe is submerged, which is the case most of the time when boat launching.

[Mark Rinker]

Some great recreation at the boatramps, for sure!

Our trailer has dual axles with hydraulic surge brakes, discs on all four wheels. The boat and trailer weigh about 9000# total. My commercial transport trailer has three Dexter 7K axles with conventional e-brakes, but no such safety interlock - thank goodness. I can see the reason for the 'feature', but mostly its just a PITA. :D

Most marinas now have a 7-pin female adapter wired to a motorcycle battery or to a single jumper 12V+ on the skidsteer or forklift they use to jockey customer boats/trailers. Everyone cusses the 'feature', since they'be been immobilized by it in the past - usually at the most inopertune moments.

[MacDR50]

We just took delivery of a new 24ft response boat with a new trailer with this feature. When we tried to back the boat into the shop with our forklift we found out all about it fast. Now we have a 7 pin connector with a small AGM battery (for safety) rigged up just to push this trailer back. Who said PITA?

[BigBlockTank]

I just installed a brake controller on my 08 6.6 2500HD. I had to find the power wire wrapped up right by the underhood fuse center. I also read in the owner's manual that to charge the towed vehicle's batteries, you must push tow/haul to accomplish this. Any one elses like this?
I just bought an 39' 06 GearBox. It really was only used 6-8 times. It had 20.9 hours on the genset when I got it. Man, I gotta get some air bags on the rear to haul it.

[TJNE]

Put a test light to the connector contact to see when its hot (tow/haul on or tow/haul off). My 07 classic is hot all the time.

[MacDR50]

I installed a 7 pin bed receptacle this weekend and used a 7 pin connector tester. My 12V was hot all the time even with the truck turned off. Same at bumber connector. I checked this with a few forums and it seems this is the standard. You can install a relay into this line that is energized by an ignition controlled(switched) circuit or just unplug when stopped for the night. I gather the Fords have the relay controlled circuit as standard in their trucks.

[a5150nut]

On my old 74 c2500 the trailer battery would energise the heater and cause it to run while trailer was plugged in. Used several blocking diodes (?) to stop the back feed. A relay would have been a lot better. Would stop the trailer from draining the truck battery too.