tail lights dont work

you will need a test light, like the judge says- poke it into the socket where the inop bulbs are- identify those wires and follow them back testing as you go- a lot of times, the sockets are corroded and just need to be scraped out and new bulbs replaced

still a no go any other ideas?

of course the fuse...which if blown should tally up the reason for failure...might have been something as simple as a hershey's kisses wrapper in the wrong spot "kissin" the fusebox~?

I just checked all my fuses, all were good. I checked the bulbs, all were good. I checked to see if I had power at the plug into the lamp, no power for the running lights. Hopped under the rear bumper and found where someone had done a crappy repair on the brown wire coming in on the main harness and it split off to two brown wires to each light and fixed the repair and lights work now.

Also each bulb has its own ground at the rear, and mine was fine.

im having the same exact issue with my 87 gmc sierra. did you figure out what your problem was?

I'm having a similar issue with my '96. My headlights, front running lights rear turn signals and brake lights all work. My rear running lights are the only lights not working. I've checked the fuses, replaced the circuit boards, replaced the bulbs, resurfaced the ground and tested the sockets. The rear running light plug is the only plug not getting power.

I had this same issue and come to find out under the hood there is a fuse for each side for the running lights that solved it for me.

On my 1994 GMC my instrument panel lights quit working and the tail lights also. I replaced the wheel dimmer switch for the instrument panel and then my tail lights also worked.

I have a 96 chevy truck hazard lights work but the turn signals stoped working any ideals fuses r good

Fuse under the hood fixed it!!! Thanks jr

I found the wires going to the tail light hang 1/2 inch below the bumper. Something hit the wires hard and cut them in two. There is a connector at the center of the back bumper.

2001 dually contractor bed front lights work properly rear light , stop lights hazard light signal lights , and parking lights doesn't work, they gone, relay and fuses, relay and bulbs are good, how to fix them?

I had the same exact problem trust me i bought all new boards lights i even followed the line what you wanna do is on the clip that has all of you wires look at the ground its the black wire go back about six inches on both sides of truck then cut and use a loose wire laying around stick it to the frame and wire you two ends to it ive fixed six different trucks with same problem and it has worked to all six so if you bought new lights and board take them back thats not the problem at gm they just throw it together trying to get done at work

Ive put in hours and hours of working on my own two now i dont have to worry some dodges does the same thing im not sure about ford

william257cash were is that clip located at

96 GMC taillights And tag light won't work. But flasher work. Check the fuses inside all good. Replaced bulbs.

Checked fuses inside and under hood all good. Come to find out the problem it was a white and black wire bolted to the frame above the trailer hitch had broken aloose . I ground them and everything started back working. Hope that fix ur problem.

Please help I have a 2005 GMC Sierra 1500 Crew Cab Vin Letter T my right side rear tail light has stopped working the stop light, the turn signal, have all stopped working and when you use the turn signal selector switch on the column when turning right it just flashes very fast indicating it isn't working, the brake light however to my knowledge is still working when you press the brake it lights up but the running light same socket, same bulb does not function I was told that the socket was burned out on one side and needed to be replaced so I went looking for a socket to fix it first not one junk yard had my model truck, and then the auto parts shops started giving me sockets to try, and none of them fit the socket design in other words they will not screw into the socket in the tail light assembly, so one store found the socket I needed none of the standard sockets will work apparently my truck was a special make something about being a transition year IDK, anyway the socket that this one guy says I need is over $60 for a socket all the other sockets I tried before were between $12 and $19, But I am not sure it is the socket this guy has been very wrong on other vehicles he has worked on for our family, in fact he ruined my nieces car they never did get it running again after he worked on it, it was running before hand, anyhoo do any of you have any clue what this might be I have checked every fuse, and replaced all the CB's in the fuse blocks and nothing

Found it was the interior headlight switch assembly. Seems with age it gets loose or, I suppose the contacts inside could be dirty. But if I move it, or wiggle it a bit, the taillights come on. Keep in mind, I can turn the knob and the headlights would come on, but not the taillights. For now I will deal with it, but I will look into either opening it up and cleaning it or replacing it altogether.

I just bought a 2012 Yukon denali and im having problems wiyh the taillights not working, licence plate light also don't work. I checked fuses and they seem good? whats next? any ideas?

brake light work also

It's usually the socket for the light itself the 3157 bulbs run hot. My resolution was switching to LED tail lights and replacing the connectors.

Check the connection at your trailer light harness

Make sure if you have a trailer light harness, to check the connection there as well. I unplugged mine and and went back to factory and everything is fixed now.

wear is the fuse u said that u replace under the hood to get the tail lights working having a hard time finding it

1998 gmc seirra brake lights turn signals and reverse light all work. Marker lights do not work. Brake light only with with head ligh switch off. I've cleaned and replaced all grounds changed the whole rear harness replaced bulbs boards does anyone have any ideas? Also when the head light switch is on the turn signals blink faster.

I plugged up my trailer and as soon as I turn on my head lights my running lights went out but the brake and signal still work.. Any ideas???

98 Chevy cheyanne, having the same issue as roger, my headlights, front marker, brake and turn signals work but rear tail lights do not work, I've trace no power up to the front connector under the brake boost. Someone has been in by the headlight switch I seen some bare wires that have been burnt off and splices installed not sure what to do next. I really need to get this thing fixed asap

Ok here is the answer to most of the taillight problems... The tab that the spade from the Headlight control switch is not making contact with the female connector on the wiring harness. If you pull the headlight switch out and visually inspect the plug itself you will probably find that the withe wire and the brown wire are discolored. (Due to its intermittent connection they heats up) The female connector on both of those wires have lost one side of the clip that slides on to the headlight switch. Inspect the wiring harness end and you should find that the harness side connector can be stretched out a bit to better meet the copper spade from the headlight switch. Only chased that for a couple of years, although this is only a winter vehicle, but still I am going to love not pounding on the switch or the dash to make my lights work!

RichKing91....think it means the trailer has a power to ground, no ground, or a bad ground.

I have a 2004 GMC Sierra my tail lights break and and running lights do not work but the blinkers do I replace the board so now I did something else I connected an wire from the trailer hitch and the break lights work with the 12v but when I connect the led tail light the break light does not work what is my problem

1990 GMC Sierra 1500 4x4 No brake lights when headlight switch is activated. Also I have no reverse lights or tail lights. I’ve checked the wire harness at the tail end of the truck and I’ve got 12 v when headlights are off but when I turn them on it goes to 0. Any ideas??

Here is a pic of truck

Ok everyone. I found my issue!!! It was the ground on the back of the truck for both tail lights. Make sure your ground connection is good and make sure all rust and paint are gone giving you a good connnevtion when you clean it.

2006 GMC Sierra SLE tallight not working but brake backup, turn signal do. Check fuses under hood. There are fuses for the rear tallight both sides that where I found my problem.

I have a 2012 3500hd with a utility box and my running lights don't turn on. brakes work turn signals work back up light works ?

2003 GMC 1500 extcab 4x4, 5.3 reg gas - Lifted the bed to replace evap regulator, notince left side lights out. Not sure when that happened, well fuses in left side of dash had short and fuses under hood had shorts, replaced the fuses all lights working great. I have LED tail lights so I know they work!! ;-)

I'm having same issue. I had my fuel pump go out. Took the wiring harness all way out two weeks ago an laid in bed. With my job I didn't get to fix it till yesterday. Got it back together an no taillights. I've cleaned out the sockets an clicked them back ten times. Still nothing. Only thing different is I didn't put bumper back on because I ordered a roll pan. So wondering if it's because u don't have the tag lights

My left tail light assy is a crazy mofo. With nothing on, brake lights will work, but turn signal is dim, fast (like when a bulb is out), and blinks tail light and turn Sig. With lights on- no turn signal, no brake light left side. With brake depressed- the turn signal makes the brake filament flash but not the turn signal filament left side. With lights on and brake depressed- backup light comes on. I've replaced both tail light assys and all bulbs. Next I'll be removing the dozens of trailer harness wires previous owner installed. Only thing that works correctly is both brake lights when no other lights are on.

I have a 1992 GMC Sierra ....I have the same problem as most of the other post.... my headlights work and so so my signal lights until I turn on my night time running lights. Then the signal lights stop working. Sometimes the rear running lights work. The brake lights don't work anytime the running lights are on . I used a circuit tester to check the sockets for each of the 3 pods located inside the rear tail light assembly .I checked the running lights, the signal lights,and the brake lights. I got various problems readings once the head lights were on, however I did find that at some point there was power on each of the terminals . My problems began when I changed out my trailer pigtail, but since then, I have removed the adapter, and made several attempts to restore the correct electrical connection . Reading everyone's comments above, I think I may have the wrong wire grounded, or the problem may be the fuses under the hood.

ShaleSurf - you have a bad ground

1999 Chevrolet 2500. Every light except the brake lights were working, bought new brake switch, light circuits, walked the wires, cleaned EVERY ground and replaced a relay. Now I have brake lights but tail lights aren't working now... Any ideas??

Hey guys I have 1981 Chevy k5 blazer and my tail lights don’t come on with head lights and my instrument panel lights stopped working when the tail lights stopped I do have turn signal tho, I tried finding the ground couldn’t any ideas?

2011 suburban LTZ 1500 left tail lights don’t work. All other lights work. Checked fuses and replaced bulbs and cleaned nearest connector to rear light. Any help appreciated.

1989 GMC Sierra....Problem: very dim brake lights, no tailights, very dim turn signals and battery gauge was "bouncing" wildly up and down when turn signal was on, or brakes applied. Problem found was at the driver's side taillight frame ground wire lug...was very loose and rusted. Cleaned and sanded frame to bare metal...cleaned tailight ground lug, installed new lug on trailer's gnd harness (was broke off) and attached both wires with new bolt to frame....and just for satisfaction in case the frame's threads are loose and corroded...I installed nut on the bolt...on other side of frame.

have a 2003 chevy 1500.. Tail lights not working.. Flash fast when they do... If I apply the brakes.. Lights (both turn signal) on the dash come on but don't flash... Apply the brakes, everything goes out... Checked all grounds.. even put in extra grounds... changed turn signal switch, flasher... I'm stumped... HELP...

forest 7073 did u figure it out im haveing same problem on my 01 gmc

Information from the expert: 90% or rear taillight issues on 1988 to 1996 GMC-Chevy trucks are systemic of only two issues: 1. Check rear ground wire (for taillights) on frame and your trailer hitch wiring and grounds. Trailer wiring should be isolated with good clean frame grounds. Many times people remove the bed frame to replace the fuel pump and stress wiring grounds or remove grounds. If you ground frame screw is stripped out as many are...drill and put a bolt with lock nut on it...get rid of the screw ground. 2. You can try to clean the taillight contacts and bend them into shape, you can ohm things out in the taillight contact paths itself. While it all looks relatively simple and flawless on those plastic taillight connectors and bi-pins...it's not! They warp in winter and summer and connections fail. Been my experience if you replace both taillight electrical housings...you can keep your taillight reflectors if you wish..they're separate. ....that's it...do these two things and make sure you have flashes and turn signals in front of truck...and you're fine. You normally won't find the issue in the front of the truck , fusing or inside the cabs. Everything is at the taillights or in the grounds at the back of the truck.

I just changed an rear passenger side wiring harness because of no break lights and now all the lights work by themselves but when the running lights are on I have no break lights and my turn signal flicks fast.