Turn signal problem...

...and the tow vehicle is a 2011 Toyota Sienna...

It's either a ground, fuse or wiring problem. In that order.

Thanks, all.
To clarify, my left running light, turn signal and brake light work fine, my right running light works fine, it's only the right brake light and turn signal that don't work.
Gary

enblethen wrote:
Check the tow vehicle for a blown fuse. many rigs have fuses that protect the trailer connector circuits. I cannot tell by your profile as to what TV is.
If no fuse is blown, use a jumper from the pop-up trailer connector battery pin to the bad side turn signal. This should tell whether issue is in TV or pop-up.

+1 on this. Drove myself nuts for the better portion of an hour fiddling with bulbs and connections trying to get the lights on my utility trailer working before hitting up Google for a solution. I could see the truck signals flashing but couldn't get the trailer to work, so I assumed there was a problem with the trailer wiring. I quickly learned that my TV has separate fuses for the trailer output and was back in business shortly thereafter.

Check the tow vehicle for a blown fuse. many rigs have fuses that protect the trailer connector circuits. I cannot tell by your profile as to what TV is.
If no fuse is blown, use a jumper from the pop-up trailer connector battery pin to the bad side turn signal. This should tell whether issue is in TV or pop-up.

AS you know this can be in either location being the truck or the trailer. I always have one of these 7-way adapters (AMAZON-ETRAILER) in my tool to plug-in the truck side and make sure those signals are working correctly. Then I know where to start looking for the problems...


7-way BLADE TESTER


Wire colors may be different depending on the manufaturer...

Etrailer.com is a great source for wiring info for the RV trailers...

My F150 Truck side 7-way connector has a pin-out decal on the side of the blade connections which helps big time when using a multimeter to check the blade readings...

I usually squirt WD-40 into the 7-way connector before plugging in the trailer. This keeps the blade connections clean for me... Some folks like to use a compound from the auto parts places that probably does a better job then WD-40 for electrical connections. WD-40 works OK for me as I always carry a PLAN B fresh can of it in my door side pocket. I just do a couple of squirts of it and move the the plug around a few times and never have a dirty connection problem it seems... There is also a roll of duct tape in my side pocket as well haha...


Might be hank of bailing wire there as well...

Roy Ken

In addition to a bad ground, it could be a broken wire or a bad connection for the brake/signal line. You could test this with a volt meter on the connections. Since it is both the brake and the signal for only one side, I'd think the issue will be found right at the light itself.

look at the brass part of the bulb the two prongs are at different levels ,they will only fit one way push down turn a bit , for your lights not working lets start simple .go to the tongue of the trailer remove the white wire bolted to the frame .clean the steel to bare metal new screw and install. now try them. MOST all trailer light problems are cussed by a bad ground. some where in the system.

If you look at the base of the bulb I think you will notice that one of the pins on side of the base is lower than the other pin. That is so it only fits in the socket one way.

I would check your grounds. If the light on the other side of the RV works then probably the ground at the light that doesn't work has the bad ground. Could be the ground or the socket itself. If neither brake light works I would suspect the plug or socket in your tow vehicle.

Sometimes I have noticed the plug itself get corrodeded contacts. I have a utility trailer that I seldom use. My running lights will work but brake and turn signals don't work. I plug and unplug the socket into my PU several times and it usually corrects the problem. They have some contact cleaner in a spray can. Auto parts stores carry it. If all else fails I spray that on the contacts and plug and unplug the plug into my PU several times.