trailer turn signal not working from truck to trailer - troubleshooting the truck side of the issue

When I made my trailer rewiring video I found out that my truck wiring had an issue. No power to just one turn signal. This video is of me troubleshooting the truck to figure out why I didnt have power to just the left turn signal.

[@bugaclay]

Thanks Dude! I've had this f150 for 20 years. With a boat trailer and utility trailer the left turn signals just wouldn't work. All else worked fine. Many aggravating hours under truck tracing wires to no avail! Never knew that the trailer wiring harness had its own fuses until your video. Checked the fuse box and there, sure enough, was the blown fuse. Then looked in owners manual under "fuses" and the it was, #20 10A mini fuse is for "trailer left turn signal and brakes". And I call myself an electrician. Many thanks again!!!

[@bucksgarage1]

I'm glad I could help.

[@kathleenedwards9849]

Thank you. Hubby has been out there an hour working on the wiring. Showed him this video. He checked the fuses and 2 were blown. The other one went to passenger window that hasn’t worked in a while. He thought it was the motor! You saved us a ton of time and $. Thank you!

[@bucksgarage1]

Glad i could help.

[@shark70007000]

Who would have thought they had a fuse for each turn signal? Thank you. The one I was working on actually tested good, when checking continuity of the fuse. It did beep showing continuity. But under a load it didn't work. So at first, I thought the fuses were both good. Then I decided to check the voltage on the fuse, while the turn signal is flashing. That's when I found no voltage on one side of the fuse. These fuses were 7.5, but I didn't have those, so I put 10 amp fuses in. Thank you for this video. 👍🏻

[@ryol1610]

This saved me several more hours trying to trouble shoot an issue with a Chevy Tahoe no right blinker on trailer but the left blinker was fine. Tearing my hair-out !! Thank you !!!

[@chrisshore5340]

+1 people saved by this video! Wouldn't have thought that the truck would work and the trailer would be on a separate circuit... assumed it was a connection somewhere and could've spent a LONG time looking for that... thanks!

[@garonsgarage]

Was at a loss as to why the left turn signal worked on my toad, behind my motorhome, but not my right. Like in this video, I thought that a signal fuse would would both turn signals. Wrong. After listening this this video, I checked and found the right turn signal fuse was burnt out. Thanking you very much.

[@MelonClips368]

FML.. I was going nuts trying to troubleshoot this same identical problem I had on my 2004 Expedition.. Thank you.. ugh.. hours later.

[@RobertDNC]

Thank you ,thank you, thank you!!! After going through all the wiring harnesses on my trailer and truck, your video found the problems. Should have watched first, would have save me 2 days of tracing wires . . .

[@jasongoot]

Thanks for posting this! I went to my fuse box FIRST and found the two 10A culprits. 5 minute fix. (2011 Silverado LH TRLR turn flasher)

[@Timelyencounter]

Thank you for this video. No one online suggested checking fuses. It ended up my issue as well.

[@iceheart3012]

A lot of times you should do that first. Unless you have access to a light inspector

[@AaronFernandes__]

Man this was an awesome video thought I was going crazy I triple checked my wiring on the trailer and everything except left turn still worked didn't even think to check the fuses lol. Thanks man awesome video!

[@lillookc]

Sometimes I find video's that help me. This is one of thoses video's. They got 15 amp in mine. Its an 02 f150. Thanks

[@kathrynfassnacht7422]

Thank you! Had the exact same problem with my truck. So glad it was something so simple.

[@kemosabe208]

BINGO! Was wondering if there was two separate circuits for Brake/turn signal. Fixed. Thank you sir.

[@scottjones6608]

I'm going to check all my fuses just to make sure before I go order new wiring harnesses I'm having the same issues passenger side turn signal tail light brake light will not work but I have driver side thanks for your video

[@ptate98]

Exactly what the doctor ordered. Thanks bro

[@timberhills1778]

Thank You very much, 2015 gmc left trailer light,found blown fuse Thanks to Your video

[@curtisrobinson8083]

Thank you so much for this video this was a life saver.

[@johnwaggoner3773]

AWESOME video!! You saved me a lot of time! Excellent!!! Thank you.

[@macgregorwiggins1285]

Exactly the info I needed.Tthanks for the video!

[@kubersingh9563]

Mct

[@Sm0kingp0wer9]

You did a great job sir

[@snorugby]

Thanks I appreciated the real life experience. I never seem to have the right fuse size either.

[@saeeda3098]

you can use the battery corrosion Control Spray it's a red liquid you spray on battery terminals you can use it for tiny little connectors like the ones on you your harness

[@hphillips7425]

2016 f250 with the same problem. After seeing this helpful video I am going straight to that fuse. Any idea what caused the fuse to blow?

[@bucksgarage1]

No idea. I haven't had any issues since.

[@hphillips7425]

@@bucksgarage1 mine was a problem with the bulb. I pulled the bulb and it tested okay. The filament was good I rotated the bulb and it showed bad. Replaced the bulb and it is good

[@nutgrower2957]

Thank you! I checked the wiring connections in the rear of my truck because the LH trailer turn signal was not working. I never would have guessed that there was a separate fuse for that one wire. Saw your video, replaced the burned out fuse and lights work great again. :-)

[@chrisjames-mh3ql]

Thank u bud saved me a whole day

[@spacecoastbonsai1421]

I bought a continuity tester and it doesn’t do anything. I can’t figure it out. My left trailer blinker and brakes are not working. Running lights are good though.

[@mitchgordon8199]

You saved my but, so I subbed. Thank you.

[@bucksgarage1]

Mitch Gordon thanks.

[@rudedude13]

Awesome. Couldnt fin the fuse in the book.. video showed me. Fuckin awesome thanks.

[@thomasfreeman9814]

Thanks for the info

[@kennethfannin8707]

i see this is old ,,, but my 2015 ford truck has the right light working but not the left ,,after reading seems like theres a fuse for each brake light /turn light ... ill check tomorrow and see if thats my problem ,, i hope thats all it is ...thanks for the video

[@bucksgarage1]

Hopefully it helps. Thanks for the comment

[@duaneh1973]

Thank you for this video!

[@joeydavis9117]

Dude you saved me.....

[@adog8]

Did your blinker light work on your truck ? And not on the trailer wiring ? I have a 2000 tacoma and that's what I'm having trouble is

[@bucksgarage1]

cody fraser yes. That was what was happening

[@bobjowers4444]

Big Thank You!

[@keithlefebre9401]

Thank you very helpful

[@kimpeter5927]

thanks for video..

[@permaguard3166]

Why do both directionals on trailer go on when I use only one in truck?

[@bucksgarage1]

Permaguard possibly a short between the turn signal wires. Try to see if the meter beeps when you put one meter lead on the yellow and one on the other turn signal slot on the trailer. It should not beep. I would bet that it would be a problem with the trailer wiring.

[@ngnmech]

The right turn signal bulb on my trailer would over rotate causing the bulb to short across both terminals. When I would turn on the right turn signal it would flash both turn signals on the trailer and all the turn signals on the truck.

[@tonymac2178]

I sure hope this is what’s wrong with mine.

[@seanclark3421]

have the same issue thx

[@707SonomaComa]

There is a separate fuse for each side of the turn signals for the trailer lights?

[@bucksgarage1]

707SonomaComa I didn't think so but that's what fixed the left turn signal for me. I'm guessing there is one for the right also.. just never had an issue with the right yet.

[@707SonomaComa]

I don't work on trailer lights all the time but someone came into the shop I work at and said another shop checked out his wiring and told him everything is perfectly fine on the truck. I used one of those little LED plug in testers and the right side lights were not working like he said has been happening for about a year now. We didn't check the fuses as the Customer said he already did and if a fuse was blown both sides stop working. Hmm...

[@bucksgarage1]

707SonomaComa the lights on my truck worked just fine. It was just the trailer that wouldn't work when that fuse was blown out, that could be his problem.

[@707SonomaComa]

Brett Buckley , only the right side trailer lights were not working. Everything else is fine.

[@bucksgarage1]

707SonomaComa I believe the fuse for the right is two back from the one that was burnt out for the left on my truck.? I could be wrong though.

[@Outdoor_Don]

I don't see a fuse box under my hood

[@mattdostal5249]

I just got my truck back from dealership. Blown fuse. $110 they charged. Who new they have left and right turn signal fuses on truck for trailer lights

[@bucksgarage1]

That's nuts. 110 for a 50 cent fuse.

[@beardedbastard_fjb614]

My yellow turn signal is bad before the flat plugin

[@nahknoffyofakinbeesness500]

I’ve made the same assumption that single fuse is responsible for both trailer signals. WRONG! Thanks for the vid. I was ready to tear the whole harness out.

[@mattharris7674]

Turns out I spent all that time basically rewiring my trailer just to realize I need to actually check things. Noted for next time. Thanks for the vid BTW, helped me out instantly.

[@gt9390]

Good job Brett

[@bachbeats2217]

Wow!!!!!!!! On Separate fuses!! This worked for me after so much headache! Thank you so much!!!

[@teenageflames]

Thanks...Awesome video,I had the same problem,but on the right side and sure enough it was the fuse.

[@lukejones7366]

Like a b o double s. Thank you so much! Check your fuses people!

[@debbielawson1447]

Thank you, man! I had the same problem and this helped me fix it.

[@roverporter2434]

I might be sending you a thank you

[@jakebody6031]

bumper stickerrrrr LOL

[@abrideforchrist4247]

That fuses you turn signal how to check my fuses for the cook my wiring harness out

[@markbardsley5880]

Dialectric grease