Trailer Back-up Lights not working

I noticed the trailer back-up lights weren't working and I believe never have. This is a 2010 Taco with towing pkg from factory and no wiring modifications. Truck B/U lights work fine. I have continuity between the trailer connector pin and the first connection in the truck cab (white plastic junction box whatever those are called), just below the fuse box.

I checked and when the truck is in reverse, I do have power at the #8 fuse that protects the trailer b/u light circuit, so the circuit should be energized.

I seem to have a break in continuity between the fuse box and the connector described above. It's a short distance (less than a foot!) but after that connector box, the wires disappear into a huge bundle and I cannot imagine how I'll trace it. Plus, the back side of the fuse box is nearly impossible to see and I can't figure out how to remove it so I can try to figure out where the problem is.

I'm sure a shop would be happy to charge mega bucks to find the problem but I am hoping somebody here might be able to clue me in on how I might be able to do this myself.

Thank you!

 

Have you checked for voltage at your rear 7 way plug? Also, I have seen trailers where the backup lights are not wired to the same circuit as the truck, or even connected at all, so check the trailer by making some jumper wires to a 12 volt battery.

 

Yes, I have checked for voltage: There is no power getting to the center terminal in the 7-way plug (that's the one to the back-up lights), that's why I don't have lights. Like I said, there is a good line between the trailer connector and the cab and there is power to the fuse for the back-up light circuit. The trailer back-up lights are on a different circuit than the truck back-up lights. The problem is in the truck, not the trailer.

 

Check the harness where the trailer wiring plugs into the factory stock wiring at the back make sure there is not a pin pushed out of the connector.

 

Have you checked the fuses by the taillight?

 

Is there a faulty ground on your trailer which would kill your lights or make them work intermittently?

 

I appreciate the replies but maybe I wasn't clear. Trailer wiring is fine (I verified that). Truck is not producing power at the center terminal of the trailer connector (truck side), which is the terminal for the trailer back-up lights. I have traced that line all the way back to the first junction in hte cab and THERE IS CONTINUITY BETWEEN THE TRAILER CONNECTOR AND THE FIRST JUNCTION IN THE TRUCK CAB. That connector is about 6" from the fuse box but there is no continuity between that connector and the fuse box.

So, that's where the problem is.

I guess it comes down to: Does anybody have some tips for how to pull that small fuse box out so I can access the wires where they go into it on the back side?

 

That's interesting Tacosioux. I have a fuse box inside the cabin to the left of and below the steering wheel and I have a box with relays and fuses in the engine compartment. I am not aware of another one near the glove box and I don't see it.

The one in the engine compartment does seem to be missing a 50A relay that is listed as controlling "Multiport fuel injection system".

Do you think that could possibly be the problem? I cannot figure out how to pull those relays out or I would pull one of the other 50A relays out and put it in that slot to see if that helps. They don't seem to want to pull straight out and I don't want to force it. Any suggestions?

 

Update: Looking inside the cover for that fuse/relay box, it doesn't look like I should have a relay there anyway. I guess the manual is more generic.

 

I'm really not a mechanical person, I googled around and figured out my problem was specific to my year and model. That's all I have for advice.

 

Thank you. I found an old seemingly unrelated thread last night where several people said Toyota forgot to install a relay in many trucks with the tow package. They showed the location behind the glovebox and bingo, mine is missing that relay. I plan to hassle Toyota today but if I get no help from them, which is what I expect, I will buy the relay online. I'm almost positive based on other peoples' experience that this will work for me as well.

Thanks again.

 

Thanks semievolved! I just started messing with my 2010 and low and behold my relay is missing also. You saved me hours of work.

 

I hope it helps you too. I found a relay on EBay for $5.50 shipped, plugged it in, and voila I have trailer back-up lights.

Seriously, I'd love to know how many Tacoma owners are affected by this. I checked my inlaws 2011 with factory tow pkg and it was also lacking the relay and had no trailer b/u lights.

Was this intentional by Toyo to save $$? Either way, they should be offering unconditional evaluations and relay installations on any affected vehicles.

 

I saw the picture but not sure where to plug the relay in behind the glovebox. Any more specifics on the location?

Thanks
Jase

 

Hi Jase, not sure what pic you saw but if you look behind the glovebox (releae the clasps so,the glovebox can open fully exposing the wiring behind it) there will be a yellow relay socket. It's just to the right of the black housing of your cabin air filter and there are thick wire bundles to the right. The socket is about 1.5" tall and about 3/4" wide. It's got two vertical and two horizontal slots that the relay tabs should fit right into. Does that help?

 

Perfect...its not there that is why I can't find it. I do have the trailer package as confirmed by Toyota so maybe when the motor was changed it came unclipped. I will search for it.

Thanks oh and dismiss the PM you answered that for me!

Jase