Brake and turn signals not working

Simmons

I have a T@B 320- CSS 2016 model.  When I got it out of storage I discovered that turn signals, running lights and brake lights are all non operational.  The electric brakes work.  I have eliminated the TV as the source of the problem. using various testing tools and trouble shooting the problem seems to be downstream of the 7-pin plug. It seems to me that the next step is to dig into the light assemblies (i.e.) pull the tail lights and turn signals) and make sure there is continuity from the front to the back and that all the grounds are good.  I'm considering ordering all new taillight assemblies after poking at the removal of one taillight and realizing that the caulking may be so intense that I will damage the lights as I remove them.

I am hoping to depart on the first trip of the season in 2 weeks.

SLJ

If they are all not working and you have power and ground from the TV then check ground. It's the one thing they all have in common.

NorthIsUp

You may have some oxidation on the electrical connectors on the trailer or TV. Use a flathead screwdriver to scrape each slot of the 7-pin connectors to hopefully allow contact. Remember to do this to both the trailer and TV.  Are you certain that your battery disconnect switch is in the "on" position? You did say that the electric brakes work, but how did you test them? 

Simmons

Thanks for your responses.  I have a diode circuit tester that will indicate ground and power.  I tested this using the trailer battery as the power source and connected to each of the trailer connections in the 7-pin.  I got ground readings on the brakes and ground but no ground readings on the various lights I've mentioned.  I also tested the power directly with each light at the 7-pin and got nada.  So I think I need to pull the light assemblies and check ground from that end.  It seems strange that  the lights are all out and I'm wondering about a break in the line but I have to go to the other end and work back I think.

What do you think of that approach.  I'm not an auto mechanic but I know if I take this to an RV shop It's unlikely I'll see this in time for my trip.

Bayliss

@Simmons, I would suggest first cleaning both the tow vehicle 7-way outlet and trailer plug brass electrical connectors with some electrical contact cleaner (e.g., CRC electrical contact cleaner.)  You can get a can at any auto parts store.  Spray all the metal contacts (with the tow vehicle power "OFF") and then insert and remove the 7-way plug into the tow vehicle outlet several times to rub all the contacts together to assist with removing any corrosion/rust.

Allow the cleaner to dry (about 10-15 minutes, but review instructions on can.)  Insert the plug into the tow vehicle outlet, turn on the tow vehicle and test your brakes and turn signals.  If that resolves the issue, apply some dielectric grease to the same brass connectors (tow vehicle and trailer) to help prevent corrosion.

Another potential problem area that you will want to check before dismantling the rear lights is the exterior electrical connections in the Junction Box (J-Box), which is likely located on the trailer A-frame at the front of the trailer body on the frame.

jbajor

+1 for j-box…. If cover is loose it will pick up road spray (salt) as well as rain water

Homebodyatheart

I just had this problem. Took my TV to a shop where they tested the 7 pin connector as fine. I had used dielectric grease on both ends, made sure both ends were clean, still no lights. Then I had a friend plug the trailer into his rig and all my lights and turn signals worked perfectly! It turns out that at the TV end behind the connection plate there is a plug from the TV wiring harness, so it’s a plug and play connection. I thought it was hard wired in. It was loose so we pushed it in tightly and everything now works perfectly! My wallet is grateful! 

tabiphile

Dialectric grease should never be applied to any terminals or electrical contacts.
It is not a conductor. It should be used to keep water away from contacts, but not on them.
Keep it out of the plugs!
Electrical contacts are designed to scrape across each other as they are joined.
That scraping is what insures a good contact. If there is a concern about the continuity, then clean the contacts/terminals with a contact cleaner. 

Bayliss

@tabiphile, the proper way to use dielectric grease on electrical connectors is controversial.  Plenty of discussion about it on YouTube, etc.

It is true that dielectric grease alone is not conductive (i.e., will not conduct electricity.)  However, it also will not inhibit the flow of electricity when the metal connectors in the seven-way plug rub/scrape against the metal connectors inside the tow vehicle receptacle (i.e., make an electrical contact.)  If the metal connectors are not making proper contact, then you need to adjust (or replace) them to resolve the problem, but it is not dielectric grease that is preventing them from contacting each other.

When you insert a trailer's seven-way plug into the tow vehicle outlet, the dielectric grease is pushed away and a proper metal-to-metal connection is made.  The value of the dielectric grease in that situation is that it lightly coats (insulates) the surrounding areas to help prevent air, water and other elements from interfering with the proper connection and conductivity between the metal contacts.  Although some will say you can be very liberal with how much grease you apply, you really don't need (and probably don't want) much.

I have used dielectric grease for my seven-way plug/outlet connection without any issues.  I also applied some to the terminals in my Junction Box at the front exterior of the trailer (attached to the A-frame.)  However, I applied it after the metal connections to the terminals was already made.  In other words, after tightening down the connectors on the terminal, I put a very light coat of dielectric grease over the terminal posts and electrical connectors to help prevent the elements (air, water, etc.) from causing corrosion. 

tabiphile

Bayliss said:

It is true that dielectric grease alone is not conductive (i.e., will not conduct electricity.) 

I put a very light coat of dielectric grease over the terminal posts and electrical connectors to help prevent the elements (air, water, etc.) from causing corrosion. 

This is a good example of how to use it.

Putting it in the actual terminal is not.

Connecter terminals by design have a scraping action as they are assembled, male/female. Believe it or not, the material selection and coating on a connector terminal is very specify and is a very carefully engineered interface. A non-conductive material is not intended to be applied to it, ever. It is possible that a well designed connector terminal may push present dielectric grease out of the way when a connection is made. That does not improve the quality of the connection, more likely diminishes it.
Further, the presence of a grease inside the connector becomes a collector of dust/dirt etc. that will find its way in. A better alternative is to use a good quality terminal cleaner to clean the contacts. 
There is really nothing controversial about this. Dielectric grease is simply not intended to be used at an electrical connection point. No one involved in connector design, manufacturing or applications would never consider compromising the terminal design with it.
Consider, a (knowledgeable) mechanic will smear dielectric grease on a spark plug or coil pack boot, but not use it on the top of the spark plus or in the spark plug connector. It's pretty much the same thing. Use it to keep water off the plug connection, but not on the actual connection.
Of course, we all may do as we choose.