Help with Trailer Lights - clicking surge brake solenoid

[seanik]

Have no lights on the trailer. When turning on hazards or turn signals the surge brake solenoid clicks as each pulse from the turn signals is sent down the wire. Only wire going into the solenoid is from the blue wire for the reverse (edited from brake, sorry for the typo) light.

All signals coming out of vehicle harness as expected when tested with test light.

How could bad solenoid stop all other lights from working?

Thanks for any help!

 

[GA_Boater]

I suspect bad gounding.

New problem?

 

[alldodge]

Have no lights on the trailer. When turning on hazards or turn signals the surge brake solenoid clicks as each pulse from the turn signals is sent down the wire. Only wire going into the solenoid is from the blue wire for the brake light.

All signals coming out of vehicle harness as expected when tested with test light.

How could bad solenoid stop all other lights from working?

Thanks for any help!

Do you happen to have disc brakes on the trailer, and if not what solenoid is on the trailer?

 

[bruceb58]

Have no lights on the trailer. When turning on hazards or turn signals the surge brake solenoid clicks as each pulse from the turn signals is sent down the wire. Only wire going into the solenoid is from the blue wire for the brake light.

All signals coming out of vehicle harness as expected when tested with test light.

How could bad solenoid stop all other lights from working?

Thanks for any help!

You have a bad ground. There is a sneak ground path occurring through your solenoid which is why it is clicking.

Take a jumper cable and connect it between your vehicle's frame and bare metal on your trailer and see what happens.

 

[seanik]

Thanks for the info so far...

Yes this does have disc brakes. Have not pulled solenoid yet as did not want to open hydraulics yet. Trailer is a 2001 Triton and does not get much use as I leave the boat on a lift year round on the lake.

Was doing some more prodding and thought I had a bad connector on the trailer as when probing the brake light (blue wire) on the vehicle side connector I was getting no light from test light (as expexted with only the hazards flashing) and ground side of test lamp was connected to same ground point on the trailer as the harness. Once I plug the trailer side into the vehicle i was getting a pulse from the blue wire.

Quickly spliced up a new trailer harness connector but still same issue. I also tried connecting just the ground and yellow but same result clicking solenoid no tail light/turn signal.

I also disconnected the solenoid wire from the butt splice in the harness but still no lights or clicking.

I guess this means I start going through all of the ground connections with a wire brush and see if that fixes. I'll try the jumper cable as suggested to start. Since all lights are not working I suspect this points to the main ground on from the harness to the trailer frame.

thanks again. Hopefully I can trace it down in the morning.

 

[smokeonthewater]

it's not the various ground connections... it's the main ground on the vehicle frame or the main ground on the trailer frame.... also while doing trailer light diagnostics always disconnect the trailer hitch from the ball.... all electric functions must work correctly with the trailer not touching the tow vehicle.

 

[CatTwentyTwo]

Only wire going into the solenoid is from the blue wire for the brake light.

I would start here and make sure your wire colors are correct, are you sure this is a blue wire or more likely a faded purple?

The brake lights should be green for right and yellow for left.
Normally a purple wire from the backup lights goes to the solenoid so that the brakes are disabled in reverse.

The blue wire is for electric brakes and you would not use it unless you have an electric over hydraulic system.

As others have mentioned, make sure you have a good ground connection. That should be thru the white wire.

Good luck.

Oh and one other thing, you didn't mention what your tow vehicle is. I've never had to use one but I believe some vehicles need a wiring adapter to work properly with trailer lights.

 

[thumpar]

What vehicle and is it factory tow package?

 

[seanik]

Still scratching my head on this one...

Drilled new ground post into trailer frame with stainless screw connected a new ground wire from new trailer harness to new ground screw, eliminating any potential bad spot in existing ground. Still same issue.

Vehicle is a Honda Pilot with factory towing package. All functions on vehicle side work properly when probed with test light.

 

[smokeonthewater]

Check ground on vehicle.

Bolted together trailer or welded?

Can have ground issues at points where trailer is assembled.

 

[thumpar]

Use a piece of wire as an extension to your meter and measure the resistance from the connection ground to the lights ground.

 

[GA_Boater]

Were the lights working and this is a new problem? Is this a new tow vehicle and it worked on the prior TV?

What connector, round or flat, and how many pins is on the Pilot and what year is it because the wiring changed over the years?

Blue wire is for electric brakes and you have hydraulic surge brakes, right? The blue wire shouldn't be connected to the solenoid. You need to find the wire with 12 volts when the TV is in reverse, usually it's connected to the back up lights in the TV.

 

[NYBo]

The blue wire for the brake lockout solenoid connects to the backup light circuit, not the brake lights. That's why the solenoid is clicking in time with the turn signals. The converter in the tow vehicle combines the brake and turn signal power.

 

[thumpar]

The blue wire for the brake lockout solenoid connects to the backup light circuit, not the brake lights. That's why the solenoid is clicking in time with the turn signals. The converter in the tow vehicle combines the brake and turn signal power.

Just for my knowledge I have to ask why the backup lights are connected to the brake and signal power? Is that something within the converter?

 

[Maclin]

If so equipped, a surge brake unit with reverse lockout will lock out the braking action when the tow vehicle is in reverse. thus needs a signal from the tow vehicle's backup lights.

 

[Maclin]

BTW, I think NYBo nailed this one.

 

[thumpar]

If so equipped, a surge brake unit with reverse lockout will lock out the braking action when the tow vehicle is in reverse. thus needs a signal from the tow vehicle's backup lights.

I understand that. So maybe the wiring is not right? I think the correct connector would be a 5 wire flat for the lockout to be added.

 

[StarTed]

Did you check the crimp connector on the trailer ground. There could be corrosion between the lug and the wire crimped in it. probe a known good ground directly to the wire, not the connector.

Once you find a bad ground connection clean and tighten it good then protect it with liquid tape.

 

[Maclin]

I understand that. So maybe the wiring is not right? I think the correct connector would be a 5 wire flat for the lockout to be added.

Sorry thumpar, I misread your post the first time.

Could be the actual converter on the Pilot is not correct for Surge brakes with reverse lockout equipped trailer..

 

[smokeonthewater]

The connection of the brake circuit will not cause light troubles whether it is right or wrong....

The color of the wire is an indicator of what signal it MIGHT be carrying...

It absolutely COULD be hooked up to function correctly with ANY color of wire....

As I see it you have one problem and one possible problem...

You can very easily test the connections on the vehicle with a test light.

I have yet to see where you answered the questions as to what has changed... Did it use to work? Did the tow vehicle work with a other trailer? Did the trailer work with another tow vehicle? Did you just get them or never use either before?

When a problem appears the first thing to do is look to see what changed to cause the problem... Next, systematically troubleshoot...

You are all over the map here just guessing and trying things....

Early on you were told to try making a ground with jumper cables..

If you would like to absolutely simplify that task, get a piece of wire that is plenty long to reach from the front of the tow vehicle to the back of the trailer...even a household extension cord will do.... Conect one end to the negative post of the battery and with all of your lights turned on use a test light and check between that wire and EVERYTHING....
From the ground in the plug on the vehicle to tongue to rear of the trailer frame to each light's ground screw.... The test light should never light up.... When and if it does light up you have found a problem area... Keep testing until you find the point that you go from good ground to no ground.. It sounds tough but this whole process would take me about 5 minutes.... I actually have a test light with a 50' lead just for this type of work.