Back to tackling that missing left turn signal...

[Bobbie Mayer]

Any ideas on how to proceed? It isn't the bulb. It isn't the TV. So it could be:

1) the 4 wire to round converter (7?)
2) the existing on the trailer round plug
3) the wire leading back to the left turn signal

I rewired the converter to make sure all the connections were good, as there was some corrosion, so I might try replacing that first. (That's the easiest fix.)

I don't have a clue which wire is which on the round plug so I don't know how to go about checking them individually.

Still too hot to work on it but next weekend we are supposed to be down into the 90s, and that means mornings are cool and I can do something with the trailer.

Bobbie

[DanPatWork]

Any ideas on how to proceed? It isn't the bulb. It isn't the TV. So it could be:

1) the 4 wire to round converter (7?)
2) the existing on the trailer round plug
3) the wire leading back to the left turn signal

I rewired the converter to make sure all the connections were good, as there was some corrosion, so I might try replacing that first. (That's the easiest fix.)

I don't have a clue which wire is which on the round plug so I don't know how to go about checking them individually.

Still too hot to work on it but next weekend we are supposed to be down into the 90s, and that means mornings are cool and I can do something with the trailer.

Bobbie

check out these links in the Document center for wiring help on the plug end.
trailer end


TV end

[Doug Mager]

Bobbie, I hear your hot spell is winding down but may lurk around there for another week or so...
I didn't check on the previous thread on this issue but here is one or two things you might try.

Can you isolate the offending light from the rest of the wiring harness and test the fixture (NOT only the bulb) for conductivity? IF it works when power is supplied directly to the light then try reconnecting the fixture (making sure its wired the way it was disconnected) and make note of the wires colors. You then should be able to trace these wires back to the trailer plug checking for broken/frayed wires as you look. First instinct for me is to always look for poor/bad grounds.

[Bobbie Mayer]

Bobbie, I hear your hot spell is winding down but may lurk around there for another week or so...
I didn't check on the previous thread on this issue but here is one or two things you might try.

Can you isolate the offending light from the rest of the wiring harness and test the fixture (NOT only the bulb) for conductivity? IF it works when power is supplied directly to the light then try reconnecting the fixture (making sure its wired the way it was disconnected) and make note of the wires colors. You then should be able to trace these wires back to the trailer plug checking for broken/frayed wires as you look. First instinct for me is to always look for poor/bad grounds.

Without removing the fixture I don't know which wire goes to the turn signal and which to the running lights. I'll take another look at it, though, and see if I can figure out where they are wired in. I've looked for loose connections and frayed wires and haven't seen any but need to go over that in more detail.

The temps over 105 are supposed to end after today. Then down into the mid 90s which is quite tolerable after a hot spell- if it cools overnight then the mornings are useful. The problem with this ultra-hot weather is that it is still too warm in the morning to do much, and the garage never cools off. Then on weekdays I'm at work during the cool part of the day.

Bobbie

[Doug Mager]

with our Trillium, we can access rear tail light assemblys by way of the under seat storage areas located either side at the raer (inside) of the trailer. Most trailers (like ours, Trilliums, Bolers etc.) have a rear table that makes down into a bed. The storage area I'm referring to would be located under these seats. MAYBE the layout of your trailer is different???

[John Perry]

Hi Bobbi,
What make is your tow vehicle? If it is a Toyota, Honda or other Asian vehicle you have a tail/ brake light convertor on your vehicle that may be bad.
Asian vehicles have their tail and brake lights on seperate circuits.
You have a convertor that combines the tail and brake lights into single circuits to operate the lights on your trailer.
Domestic vehicles have the left turn and brake light on a single circuit and the right turn and brake on another single circuit.
John

[Bobbie Mayer]

The converter wired into my car is a 4 wire one, and it has lights to show you that it is working (and it is.) But then I go to a 7 wire adapter; that is possibly bad. My first thing to do is to replace it and see if that solves the problem. I bought it new at NAPA, but when we took it apart a couple of months later it looked corroded and may not have been good to begin with.

Then the trailer has the 7 wire plug; that could also be bad. If I replace it I'm just going to wire in a 4-wire since I don't have a battery in the trailer, anyway. (But then I have to figure out which wires are important and their color coding is pretty much gone if it was ever right.)

Bobbie

[Brian B-P]

...Asian vehicles have their tail and brake lights on seperate circuits.
You have a convertor that combines the tail and brake lights into single circuits to operate the lights on your trailer.
Domestic vehicles have the left turn and brake light on a single circuit and the right turn and brake on another single circuit...

Although combined signals are traditional for domestic vehicles, lots of them have turn signals separate from the brake lights, too... but it sounds like Bobbie has already considered the converter, anyway. Converters are often required (as with my Sienna and Boler), as John explained, and I've heard of some going bad.

I would apply power between the negative/ground/return pin and each of the trailer connector's other pins, one at a time. Apparently there's no connection to a battery, and presumably none to brakes or the auxiliary pin, and each of the other three should light up an appropriate set of lights. If the correct lights don't come on, it's on the trailer side; if they do, it's the converter (despite the correct looking indicators), or wiring between the converter and receptacle, or the tug and trailer are not wired to match each other. It continues to be a game of eliminating possibilities...

[Paul from NWOnt]

Work the problem backwards. Disconnect the on-board battery, and bring it to the rear of the trailer. Use a couple of jumper wires, and connect them to the socket at the various connection points (remove bulb first), then use a testlight at the front connector to find out if there is current coming through. If there isn't, then you know it's between the socket and the plug. If there is, then you'll know if the wiring matches.

p.s. this should be done without the tug anywhere near the trailer.

[Bobbie Mayer]

No on-board battery. What else can I use as power source?

Bobbie

[Pete Dumbleton]

".Asian vehicles have their tail and brake lights on seperate circuits"

I had a GM Saturn, produced in Tennessee in the last century, which had the yellow/red turn and brake lights on separate circuits -- That was when I discovered the need for a diode block between the car and trailer.

IIRC, my '80s Mercedes in Germany also had separate bulbs, but am not absolutely certain of that (I do recall there were a lot of bulbs in the light bar in the trunk, so I think each had only one filament).

[Paul from NWOnt]

No on-board battery. What else can I use as power source?

Bobbie

Any 12 volt power source will do. In this case, you could even use the battery in your tug as long as it's parked in behind your trailer. You just need to be able to get 12volt power to the lugs in the taillight assembly.

The procedure would be the same, only the battery would be mobile. The main reasons I suggested using the on-board trailer battery was to both give yourself a handy source of power, and to remove the battery from the loop to eliminate any possible influence it may have had on the results.

You will still need the test light/volt meter, and you adapters to check them out, but now your vehicle battery will be out of the way.

Man.... I hope I'm explaining this well enough... I feel like a twit when it comes to giving directions on a keyboard.

The premise is that you eliminate the lightbulb as a possible source of trouble, while searching for connectivity regardless of possible mis-wiring of the connector (you may find the connection is in the wrong place).

[Paul from NWOnt]

BTW, the brass shell of the bulb is the ground (-), while the lead terminals on the bottom are positive.

Use caution, if you accidentally touch the 2 jumpers together, you will get a pretty good spark. It's not lethal, but will startle you.

[Brian B-P]

No on-board battery. What else can I use as power source?

Wire from the tug's battery, either using clips on the battery terminals, or a lighter socket plug. A cheap 12V extension - with a lighter socket plug on one end and another socket on the other end - can be used by cutting off the socket (keep track of which wire is which), leaving bare wire ends.

Instead of the vehicle battery, you can also use one of those portable power packs (which have a 12V battery in them and a lighter-type socket on the outside), or any AC-to-DC power adapter which puts out 12VDC and is designed to run car-type stuff in the house (e.g. one came with each of my rechargeable car spotlights). It just depends on what you have around.

I would not suggest using a car/RV battery charger. The "smart" ones will not put out power if they do not detect current flow consistent with an attached battery, so they would be quite frustrating to use.

[Bobbie Mayer]

I started with replacing the 4-way to RV plug adapter; no change. (That goes back to the store.) Then I took off the RV adapter that was wired on to the trailer to look at it, and saw that only four wires (matching the colors on my TV plug) were wired into it. So I unwired it and followed those wires back to where they were spliced into the trailer wiring about a foot back. Voila! The yellow wire (left turn) was not connected to anything. I picked the unconnected blue wire on the trailer as my best choice, twisted it on, and I had a left turn signal. Wired it properly, then retaped everything and rechecked; all the lights now work. Since that kind of left me with a mess of wires and sticky tape, I took a piece of PVC pipe, stuffed them all in, and taped it up and taped it to the trailer (will clamp it later.) Checked lights again, they still work.

If I ever decide to go to a battery (which won't happen unless I get a 3-way fridge to replace the icebox) I'll have someone else wire it all in!

Bobbie

[Paul from NWOnt]

Glad to hear it all worked out fine for you.

That's one more system on your rig that you now know better than before.

[Bobbie Mayer]

Glad to hear it all worked out fine for you.

That's one more system on your rig that you now know better than before.

LOL, not really, the rest of the wires still disappear into the trailer in a mysterious, non-color-coded bunch. I know some of them are for 12V because there are 12V lights, but that's about all I could tell you.

Bobbie