Just purchased a used 2007 Sequoia that did not have a hitch or towing package. Got a hitch online from eTrailer and bolted that up no problem. The trailer wiring is another story. I purchased a wiring adapter online for $39.00 that was labeled for the 2007 and *looked* correct in that it had two connectors which is what's back there under the bumper. But it's a no-go and does not fit, it's got different pins/connectors even though it looked good.
I called my dealer and they want $185 for the adapter
The DrawTite hitch was only $179.
I'm not going to pay $185. Two questions:
1) Does anyone know of another source for this plug-in adapter?
2) Any tips for getting a wiring diagram for the SUV so I can just
splice in my 7-wire adapter? I don't want to buy the service
manual just for this diagram.
I will save you hours of searching and banging you head on a wall. The 2005-2007 sequoias that didn’t come with a Tow package are not prewired all the way. You will have the correct wiring from the battery and the correct fuses and places to put the relays. You can see this black box under your hood with places to put a “Battery Charge” and “Towing” relay. From there all the correct wires go into a wire bundle that goes through your firewall on the driver side and comes out behind the kick panel by your feet. Down there you will find the brake controller harness that you would plug your brake controller into. (Actually, there is another harness that goes in between this brake control harness and your brake controller that Toyota put in the glove box of vehicles with the tow backage. You can get this from the manufacture of your brake controller made for a Toyota so it’s a simple plug and play.) After the break controller harness and wires from the battery, fuses and relays all meet up and go into the back of a connector that is down by your feet. There is a vertical row of about 6 connectors all full of wires that all go into a bundle and run along the floor to the back of the vehicle. I discovered that the plug that connects to the plug where all the towing wires are going into doesn’t have any of them continuing on. I found only 2 wires coming from the plug…one was for the rear window defogger and the other was for the keyless entry system. So that is where the pre run wires stopped. Had you had the towing package, all those wires would come out of the plug and get run to the back where they went into a towing converter. From there, it would go through a rubber grommet by the back bumper and end in 2 different harnesses. Then your 7 pin trailer harness would plug into those 2 connectors and then into your trailer.
I talked to 10 different dealers and they all tried to sell me their 70 dollar 4 flat pig tail. I told them all 50 times that there is nothing to plug that pig tail into. No wires hanging by the bumper. I took apart my driver side back panel and traced the wires from start to finish. I have a wiring diagram and I know exactly what color wire goes to what connector and what pin its located at.
I found all my info from this website. www.techinfo.toyota.com
Its 10 dollars a day to have access to all the wiring diagrams you need for any toyota, lexus or scion. The interface requires some getting used to but once you do, its great.
That's some excellent info - especially the techinfo site. I signed up for a 1-day pass and did manage to track down some wiring info there.
I wanted to make sure I was clear in my post about the fact that there is a wiring bundle and two connectors that emerge from under the vehicle near the rear bumper. However, after readin your post, I'm not sure if those wires are actually connected to the lighting circuits. I'll be checking that out today. If I can't find a cheaper pigtail adapter back there that just plugs in I'll just cut the connectors off and splice directly to the 7-pin connector I purchased. Using the wiring diagrams from the techinfo site at least I know what color wires are for the turn signals, backup lights, etc.
Well that will be great news if those 2 plugs are for the towing harness. It sounds like they are because that is where they are supposed to be with the towing package. They must have changed it after the 2006 model year. I have not looked at a wiring diagram for the 2007 or seen one in person but it sounds like it is it. You can get a 7 pin harness from etrailer that will have the harness with the 7 colored pins coming from it. All you have to do is join your wires to those and mount the harness to your bumper and you are done.
I studied my wiring diagram for a while and have come up with a plan to wire mine where it ends back to the trailer harness. The only thing i need to purchase is the towing converter relay, some wire and the 7 pin harness.
That techinfo site is a awesome resource. It took me a while looking at the wiring diagram to get used to the symbols and numbering/lettering of pins on the connectors.
Sorry in advance for the long post but Toyota really makes this way harder than it should be. I spent most of my Saturday trying to figure out this wiring mess. After crawling under the vehicle and doing some testing with a voltmeter it was clear that either a fuse or relay was blown/missing or there was a connector not plugged in somewhere because the harness at the back was dead no matter what I tried with the brakes, blinker etc.
So, I went to the local Toyota dealer and $72 later I had a towing relay for the fuse box up front. OK, so I took that home, plugged it in, and .... no joy. Only one of the pins is now hot and it's hot all the time - battery charging circuit I guess.
OK, scratch head, cuss, swear, call the dealership back, talk to parts guy that sold me the $72 relay and ask "OK, what else is needed to get this working?" Answer: "Not sure, but I think you need another relay next to the towing relay.". NFW I'm driving back to the dealer to plunk down another $72 for the battery charge relay. BTW - that relay must be worth $3.00. What a rip-off.
So, I rig up a jumper for the relay and plug that in. Now when I test the harness back there I get a backup 12v and running lights 12v... but no brakes or turn signals.
I look on the techinfo site and notice a trailer relay shown inside the back of the vehicle behind the gas fill door area. WTF? I proceed to take the drivers side interior rear plastic panel off to look for this relay or connector or whatever. Major PITA, lots of wires in there and connectors, some not plugged in, but no relay as per the diagram and nothing obviously not hooked up.
By now its been 5 hours since I started, I've got half the car torn up, spent $72 on a relay, and I'm really, really, getting pissed.
Next I took off the driver's side kick panel under the dash thinking something was not hooked up there. Well, again, nothing obvious and I can see some of the wires from the rear harness plugged in there.
So at this point I'm at a total loss not to mention I'm extremely annoyed. Please note also that I've rewired boats, cars, etc. and I know how trailer wiring works... at least from the 5 or 7-pin connector back. I'm pretty handy but this little project put a serious dent in my "can do" attitude. I've had 5 Toyotas but I swear my next car will be American if I plan to tow anything.
Bottom line is that NOBODY seems to be able to tell me exactly what parts are needed to get those trailer wiring connectors hanging back there live.
I was planning to take the boat out tomorrow but that's not gonna happen.
HELP!!!!
-pete
P.S. BTW, I did purchase a 7-pin connector for my vehicle from hitches4less.com - part no. HY-43385. It doesn't plug in to the connectors back there. It's for a 3 and 4 wire plug setup. What I actually have back there is a 2 and 5 wire plug setup.
Last edited by fly186; 02-28-2009 at 11:23 PM.
Reason: corrected wording
Pete,
Can you imagine if there was actually something wrong with your car and it was up to a Toyota tech to figure it out? There should be 2 needed relays up front. The towing converter relay is the one you are referring to behind your rear panel. This is the piece that I am missing so I can’t tell you what it looks like but from my diagram, it looks like it comes off the main wire bundle that runs along the floor of the driver side. I think it’s a connector that has wires going into one side and the other side is a relay. From the wiring diagram on the 06, the towing converter relay will be between the back tail light and gas tank access. It should also be grounded and I think there is a grounding block that is pretty much the first thing you come to once that wire bundle goes up and over the rear wheels. The 2 wire connector should be your hot lead and brake controller signal. The 5 wire connector will be the rest of the wires. It sounds like you have all the working functions that do not depend on the towing converter relay. It sounds like you are close.
And speaking of relays, 72 dollars is insane for a relay. I bought 3 used ones off ebay for 6 dollars a piece from a highly rated seller. New they run around 25 per relay on some online Toyota parts websites.
Hope this helps.
Wow, you have been down this road before. When I've tried to explain this to a friend he thought I was nuts and he didn't believe that hooking up the trailer wiring could be this difficult. I guess Toyota just wants to punish those who don't buy the towing package so they make it a real PITA and expensive to boot. Since this vehicle was used I didn't have the option to buy the towing package
Anyway, I think I'm close because behind the rear panel there were two open connectors - one white one which was right there near the fuel door and a smaller black connector further back right next to the tail light. I suspect the white connector is what takes a relay but which relay? I tried to pin that down on the techinfo site but couldn't see it and it doesn't seem like the same simple 4-blade relays that are used up front for the horn and tow relay.
Looks like I'll be calling the parts dept again tomorrow and trying to track down the relay that's missing in the rear of the vehicle.
BTW - I just went out on ebay and purchased a 12v relay for $6.90. I'll pull out the jumper I made for the battery charging circuit.
Again, if anyone knows what other parts are needed or has some tips on where to find step-by-step instructions for hooking up the trailer wiring I would appreciate it.
I try and explain this to the Toyota people and they look at me the same way! Your lucky yours was for the most part pre wired. Mine stops up front and its up to me to get it wired from there.
I just got off the phone with my parts guy and he gave me part number 81985-0c040 for the tow converter relay. His list price was 50 dollars. Yours should plug into the white T-10 connector. It has pins 1-3 on top and pins 4-9 on the bottom. The part you need isn’t just a typical looking relay, it has a plastic box around the relay that has internal wiring and a place to receive the T-10 connector. Scroll down on this page to see a pic on the relay Help - really confused about trailer hitch wiring - Toyota FJ Cruiser Forum
That should be all you need to finish your project. After that relay is in place, you should have turns and brake lights along with the other functions you already have. Then splice your 2 harness in the back into your trailer harness and you are done.
Thanks again. I just ordered the tow converter relay from my dealer (part number 81985-0c040) and it was $52. Unfortunately I still don't know what it looks like or exactly where it goes. When it arrives at the dealer tomorrow night I'll go pick it up and maybe all the puzzle pieces will fall into place.
Note that I called my local Toyota dealer this morning before I read your post about that part and specifically asked again if there was anything I was missing to complete this wiring. I got the cold shoulder and the service manager told me I needed to bring the car in so that a tech could look at it. The implication was that either I was an idiot and couldn't hook up the wiring properly or that I had somehow caused the problem in the first place.
That other post on FJCruisersForum was informative - especially the Toyota tech instructions for installing the kit. Unfortunately those instructions are for the FJ Cruiser and they don't show anything about that rear relay connection. What I really need is that same thing for the '07 Sequoia and that's what I'll ask for when I'm there to pick up that tow converter relay.
Good luck. Let me know how it goes.
The link to the FJCruiser page shows a picture of what the tow converter relay looks like when it has the white plug attached to it. It’s down a bit on the page.
Yeah, I see the picture now that I checked the link again. I guess I missed it the first time. I suppose the relay I get will be similar and have two places to connect two of the plugs that are flopping around back there near the fuel fill area.
I'll post an update here later in the week.... hopefully a happy one
Thanks again SequoiaMan, the trailer wiring for my 2007 Sequoia is finally working. It wasn't fun because Toyota doesn't want to make it easy for those who didn't purchase the towing package with their vehicle. Mine was used so I didn't have that option.
Hopefully I can save someone else from this nightmare with this summary on the parts required:
- 2 small relays for the fuse box up front under the hood (plus 3 fuses too)
one relay is the battery charging relay and one is the towing relay. These are
about $70 each from Toyota or less than $10 on ebay. They are the
little blue (or black) boxes - same as the horn relay, etc.
- 1 tow converter relay - part number 81985-0c040) $52. This
plugs in behind the interior panel near the fuel access door. This
is a little tan box supposedly with a computer chip in it.
- 1 wiring harness to 7-pin trailer socket. Toyota price $185. I modified
a harness from eTrailer.com instead that was $39. This harness
plugs in under the vehicle near the spare tire.
If you have a 2007 Sequoia with the 5-pin gray and 2-pin black wiring harness connectors located under the vehicle near the rear bumper but can't get power and turn signals, etc. at those two connectors, then you need to install the 3 relays mentioned above. The same thing probably applies for '05 and '06.
Pete,
Good for you. I was wondering how you were making out with your install.
I worked on my Sequoia most of the weekend and got it all finished.
I have a 06 and it is not pre wired as your 07 was. Under the hood I had all the wiring I needed with the empty relay box. Oddly enough, I had the 3 30amp fuses already there. From the relay box the wires ran into the firewall and then down to the kick panel. There they met the brake controller harness and ran into a junction box. All the wires needed for the trailer harness were there on the back side but they didn’t come through the junction box. I had to jumper the wires from there and go towards the back. I also bought a tail light converter relay which you mention in your post. From there they went into the 7 pin harness I got online. I had a wiring diagram and had to purchase all the connectors that were missing. I have lots of detailed info and suggestions on how to get this done on the 06.
Trailer Wiring Harness Connector - 2007
Linear Mode
