Car or Truck Brake Lights Not Working? How to Diagnose Tail Lights

What should you do when you find out one or more of your brake lights is out? Could be a bulb, could be a fuse, could be wiring, or maybe something else! Watch this video to find out how to trace down the problem with your brake lights, and fix the problem yourself!

Do you have other problems that need diagnosing? Check out our entire playlist of diagnostics that you can do yourself!

⚠ DISCLAIMER:
While 1A Auto strives to make the information provided in this video as accurate as possible, it makes no claims, promises, or guarantees about the accuracy, completeness or applicability of the content. No information contained in this video shall create any expressed or implied warranty or guarantee of any particular result. All do-it-yourself projects entail some risk. It is the sole responsibility of the viewer to assume this risk. 1A Auto is not responsible or liable for any loss damage (including, but not limited to, actual, consequential, or punitive), liability, claim, or any other injury or cause related to or resulting from any information posted in this video.

[AAuto]

√ *Watch the Video*
√ *Do it Yourself*
√ *Save Money*

[kikiwilson]

What if your two lower brake lights are out but the third is working?

[notSusNugget]

1:15 test light / probe testing fuses on both sides. Key on so all fuses hve power
3:38 test light testing bulb socket. Put on battery-positive to test the ground
4:20 Test light on 3rd brake light socket using the probe and a pick

4:52 if one side works and the other doesnt, then check wires to where they connect together before they get to brake pedal
5:20 IF ALL LIGHTS aren't working, most common cause is brake-light switch. Use Jumper harness...???? 5:30
If the lights work using jumper harness, the Switch is bad.

[hanssolo]

Start with the bulbs. Then go to the rear connector. Then go to the wiring harness that feeds the rear connector. If you have power at the end of the harness the problem has to be either in the taillight harness or the bulb. This assumes that you have power to the 3rd brake light and your cruise works.

[arcvidelos]

Really appreciate the knowledge here, yet I'm still without working brake lights on a 2005 Camry after going thru these steps. Bulbs, fuses and grounding wires are good, replaced brake switch as well. Got a Haynes repair manual for a 2001 camry- If I'm interpreting the wiring data sheets correctly, it looks like a " light failure sensor " connects between the brake stop switch and the tail and stoplight bulbs- tail lights are working though . My question is where is this sensor located and could part of it be defective for the brake lights and yet still allow the tail lights to function?

[krichards]

All Pro, thanks for your help, mine was a second fuse box under the dash I didn't know I had. you saved the rest of my day and maybe another to the repair shop.

[timothymercer]

Thanks for speaking English and explaining things simply

[venomninja]

My 99 ranger is giving trouble with the brake lights…. I’ll follow the vid and report back ! Great info !

[elevateyourcreativeness]

Good man you just saved me from going into hyper mode with anger. I just bought 2 led brake lights and neither of them worked initially.

I was fixing to tear my backseat apart to check fuses, then it hit me, flip the lights around. And just like magic they both worked. Thank you, thank you and thank you for the tips!

[AGarcia]

Thanks the yellow and orange wire was right on the money!!

[manuelbustos]

Yes, I have a 2003 Tahoe, 4.8 2wd. Brake light trouble began when aftermarket taillights (LEDs) that came with vehicle went out; no turn, brake, or running lights. Changed back to OEM brake light assembly, changed out bulbs and removed the adapter that enabled the LEDs to work with OE light socket. After that turn signals and reverse light (white light) began to work, and the running/marker lamps work; still no brake lights though. Changed all possible fuses in dash block as well as fuse box in under hood. Still no brake lights. Found your video about brake light pedal switch, just changed that out, was difficult because I had an extra bracket in the way. Plugged in switch, retaining clip reinstalled, checked brake lights, still not I'm at my wits end... Any further advice you can offer. Btw: the pedal is now very firm, vehicle does stop, and also the shift lever is now difficult to shift fro and back into Park... Please advise.... Thanks for your time...

[marlenalinne]

I backed into a post and busted my left rear taillight lens out. I thought I could replace just the bottom lens but that wasn't the case. The whole assembly comes in one piece and, thanks to this webpage, I found out how simple it would be to replace it. I ordered the new assembly and when it arrived, it took all of 20 minutes to change. The part that took the longest was getting the wiring harness plugged in to the new one. It just didn't want to co-operate, but I was finally able to get it done and I saved a bunch of money doing it myself. Thanks for your help. This is a very cool webpage.

[dmdltz]

Ha! I am currently having an issue with all of my lights on the back of my truck being out after installing a set of aftermarket taillights. I messed up and got the polarity wrong at first, once I figured that out I had no brake lights on the back of my truck. But you have pointed out fuses I have not checked and here I thought I checked all of them, I even replaced the brake light switch 🤦🏾‍♂️ going to the truck in the morning to check all fuses you pointed out in this video....BTW my truck is an 04 Suburban. Perfect YT timing with the video recommendation!!!👍🏾

[MrJwyne]

Good content. Always learning something new. Keep up the great content guys.

[mikbronev]

Thanks for video. First time writing on here. I own an old Toyota Matrix 2004, basic model. There's an issue with the rear brake light on the right. Left side is fine. Tried to change the bulb. it's not that. Pushing break pedal only lights the left side. I also noticed that when the engine is off, and I turn the headlights to high beams, the lights in the back also light up - and both sides. - all the lamps! I know, this sounds like a mistery. Any advice would be aprreciated. Thx.

[german]

So to test a bad ground wire I have to have a positive somewhere hooked up and touch the ground wire? Love your vids

[darrellatkins]

I have a 1961 Pontiac star chief. It has 6 tail lights.( 3 on each Side) only 1 works on the right hand side.it works on brake and turn Signal.any advice? Thanks

[arodriguez]

Would love to see this for a 2016 Accord

[CrowdPleeza]

I've tried 3 bulbs for my passenger side brake light. Neither bulb worked. I tested the bulb socket with a multimeter. Having someone pressing the brakes I got needle movement with the OHM setting. No needle movement with the other settings. So there seems to be a current reaching the bulb socket.

Is there something else I can try? The bulbs I tried are the ones given to me at the auto parts store for my car (08 Sentra).

[teeb]

You guys are lifesavers. Thanks again.