tail lights not working

[mark_fitzy]

Hey guys
Cheked all my lights as a regular check and have found the following

Brake lights working
Indicator lights workings
Number Plate Light working
TAIL LIGHTS(both of them) not working

Strange this is that the tail lights run off the same wire as number plate(licence plate)light.

Im guessing the bulbs must be blown on both, may be shorted out?
Can I replace the bulbs or do I change the whole unit on both sides.

How do I do either of them, looks to me they are sealed all around and cant see how to get them apart

 

[wellsc1]

Re: tail lights not working

your tail lights appear to LED units (not the type with replaceable bulbs). It's hard to think both are broke. Try checking wiring to each. The may be reversed in polarity. LEDs only hook up one way.

Come to think of it, disconnect each one entirely from the trailer wiring and try hooking up 12v battery directly to each at a time. If they work, it's your trailer wiring. Again, make sure polarity is right before rendering them broke still.

 

[nimmor]

Re: tail lights not working

Check your ground. I recently had only my brake lights not working and it turned out to be a bad ground. Why all the other lights were working I don't know. Grounds can be tricky little devils.

 

[mark_fitzy]

Re: tail lights not working

your tail lights appear to LED units (not the type with replaceable bulbs). It's hard to think both are broke. Try checking wiring to each. The may be reversed in polarity. LEDs only hook up one way.

Come to think of it, disconnect each one entirely from the trailer wiring and try hooking up 12v battery directly to each at a time. If they work, it's your trailer wiring. Again, make sure polarity is right before rendering them broke still.

Well picked up! I didnt even see that until you pointed out they were LED, and then I looked at the photos my self.

Looks like its going to be fun finding this gremlin.

 

[mark_fitzy]

Re: tail lights not working

Check your ground. I recently had only my brake lights not working and it turned out to be a bad ground. Why all the other lights were working I don't know. Grounds can be tricky little devils.

Hmm ground you say! I will take a look at, thanks

 

[thumbdoctor]

Re: tail lights not working

If your hauling the trailer with a late model Chevy / GMC truck, there are separate trailer circuit fuses in the under-hood fuse / accessory center. The truck brake & signal work independently of these.

 

[mark_fitzy]

Re: tail lights not working

If your hauling the trailer with a late model Chevy / GMC truck, there are separate trailer circuit fuses in the under-hood fuse / accessory center. The truck brake & signal work independently of these.

Thanks for the tip, but no I am driving a Honda CRV

 

[lckstckn2smknbrls]

Re: tail lights not working

My guess is the plug is messed up as thats the point where the running light wiring comes together.

 

[boat1010]

Re: tail lights not working

Probably 90% of trailer problems are ground problems. Check and clean all the grounds. Lots of the trailers just use the trailer for the ground so each light has a ground connection there. So it is like your car. the frame is the return for the path for the electricity. Each light hast to have a path back to the battery. All you need is a 12 volt tester and start at the plug to see if you have power there and work your way back to each light.

 

[mark_fitzy]

Re: tail lights not working

Well, I spent the afternoon trying to figure out what the hell is wrong. I must be doing something wrong I guess.

I started from the trailer plug on the car and tested all wires with test light, tick all good

Then I plugged the connection from the trailer to the car and tested the Trailer plugs wires with test light, Tick all good.

I then went to the back of the trailer where the lights are and sliced the Tail light wire(Brown wire) to show bare wire and connected test light to that, put test light ground clip to trailer and point of test light to bare tail light wire, No power.

so for a test I connected a wire from the licence plate light to the tail light bare wire , Still nothing

So for a test I thought I would slice a bit of (Red wire)Brake light wire and try the test light on that while at the same time I had somebody press the brake pedal, and the brake light came on but the test light didnt???


I also noticed when the licence plate light was on and working I put the turning signal lights on at the same time and I notice that a slight blink on the licence plate light.


For another test I connected a wire from the licence plate light to the brake light and it wouldnt come on and I noticed when I did that the licence plate light went off ???



Oh an I cant find the ground anywhere but at the trailer plug
Im so confused

 

[kenmyfam]

Re: tail lights not working

I've said this a lot but here we go again.
The 3 top reasons for trailer light issues.

#1. Bad ground
#2. Bad ground
#3. Bad ground

A bad ground gives some pretty strange results in trailer lights and a wide variety of different symptoms. If this is a bolt together trailer then reef on all the bolts.

 

[SSScout]

Re: tail lights not working

Switch to LEDs tail lights - they bolt into the same postions as your existing lights and last forever - you're wiring may need to be replaced as well - the harness is cheap.

In the long run, its a lot cheaper to be safe - and avoid tickets for no tail-lights!

 

[JimS123]

Re: tail lights not working

Switch to LEDs tail lights - they bolt into the same postions as your existing lights and last forever - you're wiring may need to be replaced as well - the harness is cheap.

Int he long run, its a lot cheaper to be safe - and avoid tickets for no tail-lights!

The fact that he already has LEDs was established in the second post.

You have a bad ground plain and simple. The trailer looks corroded, so the wires are probably corroded as well.

Follow all the wires and locate the ground connections. Then remove the wires, polish the metal parts and reinstall with new bolts/screws. That includes the lights themselves, as they also need that ground connection.

When you go back to test them, install the trailer on the towcar. If that final positive ground is not established your lights may appear dim.

 

[kilroy1984]

Re: tail lights not working

I had the same type of problem with my truck a 1999 f-150 found 2 damaged wires fixed them and still had no right side lights looked at all the wire under the truck nada finally looked at fuses sure enuf it was blowen works great now check those fuses and rule them out the bare wire could have blowen it

 

[mark_fitzy]

Re: tail lights not working

Thanks Guys for your input.
I have already followed the wires all along the trailer and I cannot find a ground anywhere. I will keep searching

 

[Kevinmcm]

Re: tail lights not working

Hateto ask this, but is the trailer hooked to the ball? if so run trailer around the block and start testing again, sounds like a definate ground issue. As a last resort, try hooking jumper cable from trailer to frame of car to establish a ground you know to be good

 

[mark_fitzy]

Re: tail lights not working

Hateto ask this, but is the trailer hooked to the ball? if so run trailer around the block and start testing again, sounds like a definate ground issue. As a last resort, try hooking jumper cable from trailer to frame of car to establish a ground you know to be good

Great Idea, I will give that ago

 

[JimS123]

Re: tail lights not working

Thanks Guys for your input.
I have already followed the wires all along the trailer and I cannot find a ground anywhere. I will keep searching

The trailer side of the plug has a white wire. That's the ground. It goes to the ground conection and its usually there in less than 3 feet.

 

[Mi duckdown]

Re: tail lights not working

The ball to coupler should never be used as a ground.
Remove the trailer from the Veh. Hook up harness and check from there. The white wire on the trailer pig should grounded/ bolted to the trailer.
As said before grounds are funny.

 

[Kevinmcm]

Re: tail lights not working

I understand grounding thru the ball is less than ideal, however, it does work. Thats why I suggested a jumper, if the previous owner didnt hook up the ground on the pigtail, or the ground on Veh. isnt thru the pigtail, then thats the only way left to test. I use a 7way with my boat< and run a seperate 12ga. wire for ground alone.