GMC Acadia Forum banner
1 - 16 of 16 Posts

·
Registered
Joined
·
281 Posts
Discussion Starter · #1 ·
Hi everyone-

I have posted a couple of times and I thought through all of your helpful posts that I ordered the necessary parts to turn our "non-equipped" tow package Acadia into one that could tow. I just got the fuse block replaced under warranty and I have the hitch and brake controller on order. I even purchased the receptacle, which I thought after reading the posts, was all I need to connect to the wire harness under the rear bumper. Well, when I went to pick up the Acadia, the service guy gave me two part numbers that he said I needed to complete the wiring in the back. GM part# 25826858 for the harness and gm part#12191503 for the receptacle. Now I am super confused. I thought I just needed the receptacle. Would someone who has converted their "non-equipped" tow package Acadia into one that can tow tell me if I need to order this harness as well? Thanks in advance for any help.

Bill ???
 

·
Registered
Joined
·
1,703 Posts
I have not done mine yet, but have been taking notes. From what I have noted, you need the receptacle, harness, and insert. The receptacle is what the trailer plugs into. The harness connects the receptacle to the wiring on the car, and the insert(optional) is the black piece that covers over the hitch when not in use. It replaces the insert that came with the car and has a bump out to give room for the hitch.
 

·
Registered
Joined
·
428 Posts
Bill, you do need the harness to complete your wiring. It plugs into a plug by the passenger side rear wheel well. You will have to reach up into the space behind the wheel well and feel for the plug, it is held up by a plastic pin, you can pull the plug down so you can see it to plug the harness in and then plug it back into the hole when you are done. The 07 year models dont need the harness as they were equipped with them from the factory. The 08's were not equipped with the harness do you have to buy it. Hope this clears up the confusion for you. If you need help finding the plug behind the passenger side fenderwell your service department should help you find it.

Derrell
 

·
Registered
Joined
·
1,703 Posts
dfrank78 - According the Bill's signature, he has an '07 which based on your response might indicate that he does not need the harness.

I know that the plug for the 08' was above the wheel well and I thought the plug for the 07 was up above the bumper in the middle somewhere. I thought that they both required a harness and that they were just different. Based on what you indicate, both the 07 and the 08 have the plug above the wheel well, but only the 07's have the harness taking the wiring over to the bumper.

who1975 - Have you looked to see if you have the harness on the car. If you have an 07, my guess is that the harness is already there.
 

·
Registered
Joined
·
428 Posts
I didnt notice he had the 07, from what I have read on the 07's the harness is already under the car. The location is in a thread on here somewhere, if you search for it you should find it.
 

·
Registered
Joined
·
281 Posts
Discussion Starter · #6 ·
Thanks everyone for the replies. There is a harness underneath the rear bumper towards the driver's side. I was hoping that all I had to do was plug the receptacle into this harness. I guess, I will wait until my receptacle comes and then try it. I will report my findings to all of you once it comes in a day or so. Thanks again for the help. I am so close to being ready to tow our used-but-new camper that I can taste it.

Bill

PS> On a different note, the camper that we bought is about 3500lbs. fully loaded. It has a anti-sway bar on it already. I am getting a transmission cooler installed on Tuesday. Do you think I need a WDH or I am I good to go? Thanks again.
 

·
Registered
Joined
·
104 Posts
On my 07 Acadia i replaced the fuse box myself. I added the hitch myself. I also replaced the harness from the passenger side wheelwell because the original will only power the tail lights. I then ordered the receptacle with a 7way/4way that plugs into the harness. The only thing i haven't done yet is install a brake controller and do the mod under the dash to the BCM for the reverse light wire. I'm not sure i'll do that mod since i don't plan on towing anything with surge brakes. The connector for the brake controller is tied up to the harness next to the BCM.
With the new harness i have 12v power at the receptacle, right/left turn signal, brake lights, and tail lights.
 

·
Registered
Joined
·
381 Posts
For all interested future llamda owners reading the tow threads...

BUY THE TOW PACKAGE.....BUY THE TOW PACKAGE...BUY THE TOW PACKAGE...
 

·
Registered
Joined
·
281 Posts
Discussion Starter · #9 ·
Hi everyone-

I have an update. I received my receptacle today in the mail and I plugged it into the harness that I found tucked underneath my rear bumper on the driver's side. Perfect fit. However, I am curious, when I looked at the narness under the bumper, it looks like there is only 4 wires going to it. I thought the receptacle was a 7-pin (7 wire harness) plug. Remember that I know almost nothing about trailer wiring since most vehicles I have towed with in the past all have come with the 7-pin plug already on it. Are there wires missing from this factory harness? Or is there only supposed to be 4 wires going back there? Also, I am getting ready to hook up the brake controller I bought and am worried that there might be additional wiring that needs to be done instead of the plug and play harness that I ordered from Tekonsha. Once again, thanks in advance for any replies.

Also, I have a 2007 Acadia with the "non-tow package" equipped vehicle.

Bill

PS. I agree with Jake_99: Buy the tow package and save yourself the hassle! Thankfully, my fuse block was replaced under warranty!
 

·
Registered
Joined
·
1,703 Posts
Jake_99 said:
For all interested future llamda owners reading the tow threads...

BUY THE TOW PACKAGE.....BUY THE TOW PACKAGE...BUY THE TOW PACKAGE...
I totally agree. When my 2008 Acadia came in, I looked at it and said "oops, you did not get me the tow package". The salesman showed me the spreadsheet I printed and gave him and sure enough, it was my mistake and I did not ask for the tow package. (although I intended to)

He gave me the option of putting mine into general stock and ordering me another, but I had read about the warranty coverage of the fuse block so I took the car figuring I would update it.

Now the 2008s are not covered for the fuse block and I wish I had gotten the tow package.

If you are getting an Acadia..BUY THE TOW PACKAGE.....BUY THE TOW PACKAGE...BUY THE TOW PACKAGE...BUY THE TOW PACKAGE.....BUY THE TOW PACKAGE...BUY THE TOW PACKAGE... :)
 

·
Registered
Joined
·
104 Posts
As i mentioned in my other post, the harness only has 4 wires in it. With that harness the only thing you'll have is tail lights. You need to replace the harness with one that has all the wires. The harness i ordered from gmpartsdirect is: 25845097. According to their site the cost is now $35 plus shipping/handling. With the new fuse box everything works except for backup lights.
 

·
Registered
Joined
·
281 Posts
Discussion Starter · #12 ·
JLF-

Was it difficult to replace the harness or a simple plug and play. Do you have recommendations as to how to do it? If I add my P3 brake controller, will I need to do any additional wiring for it to work? Thanks.

Bill
 

·
Registered
Joined
·
104 Posts
The harness is held in with plastic clips along the rear frame. I just used a flat blade screwdriver and pryed them out. I loosened some of the screws along the fenderwell for easier access to the connector. You'll have to remove the old one by pulling it toward the driver side and feed the new one back from the drivers side to the connector at the wheelwell and just pop the new clips back in the holes.
I haven't added a brake controller yet, but i know some will just plug right into the connector under the dash on the drivers side. If you want the reverse/backup lights to work, you'll have to have the mod done to the BCM. If you have a trailer with surge brakes the back up power needs to be there to prevent the trailer brakes from engaging when backing up.
Jerry
 

·
Registered
Joined
·
281 Posts
Discussion Starter · #14 ·
Jerry-

Thanks for the helpful tips. I have one more question for you. When I was looking under the Acadia today, I looked under each wheel well and found what I think might be the connector that you are talking about on the passenger side. Is this the one I am looking for. It was pretty high up and pretty tight up in there. I wasn't sure if it was a connector going to the passenger side tail light or to the tow harness. Could you give me some clarification as to what I should be looking for when I get the new harness to plug in? Thanks again.


Bill
 

·
Registered
Joined
·
104 Posts
That should be the one. It's up quite a ways and that's why i removed some of the screws along the wheelwell. It's still tight getting to it, but it can be done. If you're going to get the other harness, i would wait until you have it in hand before taking the old one out. I forgot to add, i also used needle nose pliers on some of the clips that were fairly easy to get to. Hope this helps.
Jerry
 

·
Registered
Joined
·
281 Posts
Discussion Starter · #16 ·
Jerry-

Thanks for the reply. I will order the new harness and then hopefully attach it to the one on the passenger side. Thanks again.

Bill
 
1 - 16 of 16 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top