View Full Version : RTH - Connector Help

03-25-2012, 02:43 PM
I'm troubleshooting an issue I have with the passenger's side taillight on the T, specifically it does not illuminate when the pedal is pressed, but the bulb works when the headlights are turned on. I'd like to try to eliminate an aftermarket trailer wiring harness as being one of the possible causes. The connector being used on the harness closely resembles one of these:


For the life of me, I can't figure out how to get the thing apart. Can anybody lend some insight? This is the connector being used for the passenger side taillight on my '97 T100.


EDIT: Here's a crappy pic of the actual connector

EDIT X2: Looking at the electrical wiring diagram, this connector appears to be labeled R6 R7 Gray

03-25-2012, 05:43 PM
gotta be a way to push from each side while pulling the thing apart. Sometimes you need 3 or 4 hands.

03-25-2012, 09:45 PM
My manual describes using an SST to move some kind of retainer inside of this type of waterproof connector... I believe this is the waterproof connector. It even has illustrations and everything, I just can't wrap my head around the pictures or procedure it describes :confused:

I'm going to pay a visit to Groove this week because I'm going to end up replacing that bit of wiring harness for the taillight assembly. Hopefully I can get some of their advice about this particular connector when I pick it up.

03-25-2012, 11:51 PM
Looks like you could shove a flat blade screwdriver at that little lever.. push it in, then twist the screwdriver to pry it apart. Aim the screwdriver right at that dark rectangular spot on your picture.

03-26-2012, 12:15 PM
Just to ask the obvious, but are you sure the bulb is good?

You said the brake light is out but the running light works...As I recall they are separate filaments.

As for the connector...I would assume you press down on the ridged part while pulling apart but I know fighting with these connectors can be a real PITA. I know the NSS on the later model 80s can be a bi$%& to get off and this has a similar look. On the NSS connector, I got it off by pressing in on the ridged tab with a screwdriver while using a flat head to pry up on the sides. Of course on the 80 the end that the NSS connects to is attached to the tranny vs. having two loose connectors.

03-27-2012, 08:29 PM
Bulb appears to be fine. I went ahead and stopped by Groove this afternoon, they were able to order the part I need so I should have it by Thursday. When it comes in I'll ask around to see if someone in parts, possibly even service, can explain to me how the connectors work...

I have to admit, having a bus pass is nice. I'm not under much pressure to half-ass repairs to get the truck back on the road, and I'm feeling good about doing it the right way. Will keep this thread updated...

Air Randy
03-28-2012, 09:23 AM
'course if you had bought an F150 you wouldn't be having these issues, dang Toyota's :D

03-28-2012, 12:08 PM
Bulb appears to be fine...

Don't they all? :hill:

Did you try swapping bulbs with the other side that is working. That should quickly rule out the bulb and only take a few minutes :thumb:

03-28-2012, 12:20 PM
T harness are infamous for going bad.

They are also model year specific. Your best bet is to get a new connector set and splice in. Also make sure you the truck doesn't have a factory trailer harness. It piggy backs on the harness and can be corroded through.


03-28-2012, 12:57 PM
This connector was bad on mine when I got it, but was due to the first owner's trailer harness. The splice was the epitome of 'ham fisted' and, like John mentions, was just as green and covered with scale as you'd expect would be copper exposed to road grime.

Not sure if it was factory or UHaul harness, but it was installed with those 3M snap-on quick splices. Pretty sure right after sketching up 'IFS' on a napkin, satan himself thought those things up. Oh sure, they're fast and work well for a year. But they end up cutting half the wires and in the process of cutting the insulation they leave the whole termination exposed to just corrode away.


I ended up cutting, soldering and weatherproof shrinking a new section in back there. That's going on 12 years old now. This was the section under the rear of the bed, right behind the vertical section of apron. Talk about a pain in the back, can't quite lay down, can quite sit up.

03-28-2012, 04:17 PM
I agree Dave those things are the devil, I don't like 'em. Maybe for something in the dash, ok, but definitely not out under a truck bed.

03-28-2012, 05:17 PM
Don't they all? :hill:

Did you try swapping bulbs with the other side that is working. That should quickly rule out the bulb and only take a few minutes :thumb:

Kinda late for that, I already have the PO's rats nest taken apart but I have a good idea about what is going on. It has the stock trailer harness, but the functionality of that unit appears to be fine. I tested the trailer connector before digging into everything and it was sending the electrical signal to all the lights just fine... except for the passenger side brake light.

It was set up with those pesky plastic splicers, my plan for the repair is to do some good soldering to mitigate having to deal with this issue again down the road. I have a part on order from toyota that should allow for a quality repair.

Lucky for me, the engineers had their thinking caps on when they designed the rear combination light/wiring setup on these trucks. From the fuse box, the wires run along the under side of the bed to the back of the bed. From the bed to the housing, there is a separate bit or wiring harness that connects using that plastic connector I couldn't figure out.

I'm replacing the old, hacked up bit of wiring harness that the truck has with a shiny new one, and this time when the splices are made to hook up trailer lights, they're going to be done much better :D

03-28-2012, 05:27 PM
I'm replacing the old, hacked up bit of wiring harness that the truck has with a shiny new one, and this time when the splices are made to hook up trailer lights, they're going to be done much better :D

Interesting...So you think the stock harness used those crappy splices?

I chased an issue with my trucks trailer wiring for a long time. Everything would work on my popup except the aux lighting so I couldn't tow at night. In the end I replaced the crappy Draw-Tite dealyo (supposed powered unit to bump up the juice to the rear but it stopped working :rolleyes:) and crappy splices the PO made with a Hoppy plug-n-play unit. No splices needed :thumb: - it is all connectorized...unplug the OEM connector, plug in the Hoppy connector, plus the OEM connector back in on the backside of the Hoppy and voila.

Just a suggestion but you might want to spend a little more $$ now and change out the hitch/trailer wiring with something that doesn't have splicing involved.

[EDIT] Looks like Hoppy Part #43355 (http://www.hopkinstowingsolutions.com/products/vehicle_wiring_kits/wiring_kits/toyota_t-100_94-98_tacoma_05-08.html) is what you need

Under $50 on Amazon - LINK (http://www.amazon.com/Hopkins-43355-Plug-In-1994-1998-2005-2009/dp/B000C3HBX4/ref=sr_1_1?ie=UTF8&qid=1332973892&sr=8-1)

04-03-2012, 09:05 AM
Back in business :)

The connector ended up being relatively straightforward, there was a clip that needed to be depressed that resides under the cover on my second picture. It ended up being lodged with Moab-style grit (which makes sense, the truck is originally from Utah). Getting the two sides apart required a bit of muscle and resulted in a scraped knuckle or two, but ultimately I got the taillight working again. Still have not replaced the trailer harness, that will be a project for another day.

As a brief aside, I filled up the truck last night and discovered that with about 70% highway, 30% city driving, I was able to achieve 19.8 mpg. Albeit, was on the premium fuel that I used to pass my emissions test. Even still, this is right in line with what I was getting on my last truck. Its a good feeling knowing I have a truck capable of 20 mpg+.