Help! Towing Plug Wiring Reverse Lights

So I bought some LED lights at walmart for like $20, they're small and low profile but pretty bright. Anyways, they came pre-wired and all that. So I mounted them on my tow hitch bar, and the plan was to just tap into the towing plug wire harness thing, and get the power there for the reverse so the LED lights come on when I go into reverse...so without doing much research(seemed pretty straight forward) I went ahead and attempted it yesterday. I took off the plug harness, and lowered it and opened it all up, and on the cover it says Backup Lamp is the center pin, and looking at the back all opened up, the one that went into the center was a yellow and silver striped wire, so i cut it, and soldered the wires to the leds and yellow all together, than electrical taped the shit out of it, sealed basically all of it backup, but decided to try it before I got it all perfectly sealed for good...so I turn the ignition on, put it in reverse(w/ emergency brake on) and the lights dont work, but my stock reverse's are on...so I try it again starting the truck(e brake still on, i was in garage) and they still didnt work...so i took some wire and connected it to all the pins in the towing plug and the only one that lit it up when truck was in reverse was the battery positive one..obviously...so idk what to do...did I do something wrong?? can I not tie into the tow plug or what? Any help is appreciated..I can get pics too I guess

EDIT: Could it somehow not work cuz the e-brake is engaged? I know my DRL's don't come on until you disengage the e-brake..idk that's just a thought.

Oh and I also have the Fog anytime mod where you add a wire to tow tail relay(so atleast park lights have to be on for fogs to come on)...could that be interfering somehow?

 

The yellow wire is the right wire. The center of the trailer socket is the right terminal for it. It's normal for nothing but the battery terminal to be powered on the trailer socket under the conditions that you described. If the stock BU lights are on, then the trailer socket yellow wire should be, too. The e-brake and fog light mod shouldn't affect the BU lights.

Check the BKUP LP fuse in the interior fusebox.

If that doesn't fix it, check the backup lamp relay. If you pull the glovebox out, it's to the left of the two ECUs. It has one each of green, red, yellow, and white/black wires connected to its socket.

If that doesn't work, you can always connect to the red wire going into the tail light.

 

Okay, I may check the fuses here soon, what should I check them for? pop them out or what? And I'm just stumped as to why the LEDs didnt work...the stock BU lights DID light up, so the leds should have! I did all the wiring correctly, and grounded them out correctly..I'm just confused...and I know the lights work, I tested the on the battery real quick right after I got them, and they both lit up when I tried touching them to the battery terminal socket in the tow plug...

 

Pop out the fuse.

If you have an ohmmeter, test the fuse. Shorted (a fews ohms or less) is good, anything higher is bad.

If you don't have an ohmmeter, look very closely at the fuse and see if the metal link inside is broken. If it's broken, the fuse is bad, If it's not, the fuse is good.

Based on what you described, your new lights are good and you didn't do anything wrong. The trailer backup light circuit has its own fuse and relay separate from the OEM backup light circuit. Most likely, the fuse or relay is bad or missing.

 

Alright thanks man, I'll try that...if that doesn't work..I guess I'll just try to tie into the stock reverse :/

 

This is from a thread I started some time ago and the fix is stated in the quote above. Hope this resolves the issue for you.

 

Nick54,

Can you provide any details on relay behind glovebox? I have exact same situation. Reverse lights not working on 7 pin factory towing connector. Everything else works fine. Have checked all fuses.

 

Just want to close this out for future use. Apparently, many trucks were manufactured without including the back up light relay when factory towing package was orderd. Relay is right behind the glove box. Toyota relay part # is 90080-87026. This relay is about $70 at the dealer or $15 at Autozone (Duralast # 41-5465). This is same relay as fog light relay.

 

I did this a few weeks back. A quick way to check if it's your wiring or the fuse is to check the voltage on your trailer plug it self. If you don't get ~12v between the center and ground of the trailer plug, then I would move on to checking the fuse and relay.

Also I don't know where you tapped into the backup lights, but when I did it, underneath the truck you can unplug the entire trailer plug system, which is where I tapped in. Initially I had unplugged this to work on it, I had also forgotten to plug that back in so when I turned the truck on, my new LED's didn't work. Took a while to figure out that I didn't plug it back in.

 

Any pictures of where this relay is plugged in?

 

Also don't forget to check the ground wire on your lights.

 

Ok, it works....order the relay, and this is where you plug it in.

 

I want to thank the posters here who provided parts numbers and a great photo of where the relay should be. My2010 Taco with factory tow package was also missing the relay as well as my wife's parents' 2011 TRD OffRoad.

I wonder how many thousands of trucks were bought without this relay and how many hundreds of thousands or millions of $$ Toyota saved by not installing them in the original vehicles. I wonder if it was intentional. FOr those of us who are out of warranty, they will do nothing.

This seems very wrong to me. I'd like to find some way of collecting a list of people who are in this position and consider action against Toyota. I bet that many many people who buy these trucks never realize the relay is missing.

 

Much thanks to all the posters in this thread. Mine was AWOL as well. After two hours of voltage testing and pulling what hair I have left out, I searched and found trusty tacomaworld to come through. Again. Surge brakes need the trailer backup lamp to actuate the solenoid on the brake reservoir, freeing up the brakes to backup. Very helpful guys. Thanks a million.

 

Thx for this info. After having this taco for almost 3 years and having a heck of an issue trying to back a boat up with elec surge brakes and having to wire a lead to the back up lights...urrrr. Went and got the relay and now there is power at the center post.

Now the frikking 7 pin loses power intermittently to several post so I don't have brake lights or running lights or whatever at any time. What a joke!