tailights

The Era of The Square Body Racing Comets
smithhe
Posts: 148
Joined: Mon Jun 18, 2018 2:22 pm
Location: Southern Maryland

tailights

Post by smithhe »

Hi i have been having this problem for a while now and its starting to become a problem with the local authorities when I drive past sundown. The taillights on my 1964 Comet 404 work when I press the brakes but the running taillights do not work anymore. It has been like this for a couple months now and for a period of time they would turn on after about ten minutes of driving but now they wont turn on unless I press the brake, I checked the fuse and replaced it which did nothing, and all the wires in the trunk I checked and none seem to be unplugged or messed up. If anyone else has had this problem I would love to hear how you fixed it or if anyone knows how to fix it.
1964 Mercury Comet 404 with 347 stroker
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Lou's Comet
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Location: Jeannette, Pa.

Re: tailights

Post by Lou's Comet »

Little confused on your post.

Your tail lights come on when you press the brakes ?? Or do you mean your brake lights are coming on??
Do your rear turn signals work?
Do the front parking lights work?

Your rear tail light bulbs are dual filament, one filament is for the brake and turn signal (the brighter filament), the other filament is for the tail light/parking light (the dimmer one)

First thing to try is putting in new bulbs, when you do this check the condition of the inside of the bulb sockets for corrosion or damage.

Can help more after knowing the answers to the above questions .

Lou

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SASSY
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Re: tailights

Post by SASSY »

See if there is energy in the taillight leads in the trunk, check the sockets and bulbs. Ensure there is ground and the pigtails are clean.
Pull the switch out and check it for connectivity.
Thee problem is most likely simple, but to find it :x :x
I'd rather do it myself if it's done right or not,,,isn't that what hotrodding is all about

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smithhe
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Location: Southern Maryland

Re: tailights

Post by smithhe »

thank you guys ill pull the bulbs tomorrow and replace them and check the sockets and everything. and yes sorry about the confusion, the brake lights work, the running lights do not, but the rear and front turn signals work, the bulb filament idea does sound like it could be it so ill replace the bulbs tomorrow and let you guys know what happens
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Lou's Comet
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Re: tailights

Post by Lou's Comet »

smithhe wrote:thank you guys ill pull the bulbs tomorrow and replace them and check the sockets and everything. and yes sorry about the confusion, the brake lights work, the running lights do not, but the rear and front turn signals work, the bulb filament idea does sound like it could be it so ill replace the bulbs tomorrow and let you guys know what happens
As Fred said. The problem is most likely simple but finding it not always simple.

But you can narrow it down by what works.

Since your rear brake and turn signal lights work correctly I think it would be a safe assumption that the ground is good. The brake/ turn signals share the same ground as the tail lights, so if ground was bad the brake/turn signals wouldn't work right

Assuming your headlights work I would think you have power coming in to the light switch.

This narrows it down to :

1) the bulbs
2) the sockets
3) the feed wire from light switch to tail lights
4) the light switch

Changing the bulbs will show if they are bad

Inspect the inside of the sockets, there should be two contacts, one for brake/TS filament and one for the tail light filament. They are spring loaded to keep a good contact.

To test the feed wire and switch, take a test light and ground it good to the car body or tail light housing. Then take the probe end and test for power from the tail light feed wire,(from what I seen on a wire schematic I found on web the wire should be black?
You can test the wire at one of the connections or test it thru the tail light contact in the socket.

If you have no power it could be the wire or switch, next you would have to test for power at the tail light feed/tab on switch. If you have power at the switch but not at the rear of car then I would think the feed wire is bad. If no power at the switch connector then bad switch.

Couple random thoughts. Keep in mind that the ground is the socket touching the tail light metal housing. If you pull the socket from the housing and try a bulb it will not work without grounding the socket.

When testing for power at the rear what I would do is turn on the key, turn on lights, then turn the left rear turn signal.Then take the test light and test both wires going into a left rear socket. One should make the test light blink and the other wire will be the tail light feed, and should just light the light.
This does two things, first it shows the test light if grounded and working and second it will help you distinguish which wire is brake/TS and which is tail light.

Hope this helps

Lou

popscomet
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Re: tailights

Post by popscomet »

Even tho this is not your problem fixer,,,yrs ago my lights went hay wire to the high heavens,,,long story short ,I finaly located a tail light bulb that had one end of a filament burnert off and feel down on the other filament and welded itself to it,,that caused me more headache for awhile...wasn't on my comet,,,reading your post made me think of it...good luck pop
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smithhe
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Location: Southern Maryland

Re: tailights

Post by smithhe »

Thank you guys again for the replies, I swapped out the bulbs on her today and it still has the same problem. I checked all of the connections in the sockets and they are all very clean and nothing seems to be messed up, I’m going to get a voltage tester from my dad here soon since I don’t have one and check all the wires and connectors to narrow it down. I don’t know if this makes a difference but before this problem started happening I was blowing the fuse to the taillights about once a week for a month straight, I couldn’t find the problem and then after about the fifth fuse replacement it stopped blowing the fuse and then a month or so later this problem started happening, so I’m not sure if it could be a problem in the fuse box or what but I’m willing to bet it’s a problem in the switch, I’ll check it all once I get a tester and let you guys know what happens.
1964 Mercury Comet 404 with 347 stroker
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tomb22
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Re: tailights

Post by tomb22 »

Sounds like you had a short in the wire going to the tail lights and by replacing the fuse the wire finely burnt to the point that it's not a solid wire anymore. I would look over the wire really good. I would get one of those 12 volt testers with the sharp needle and lamp; then start at the switch and test the wire coming out of the switch and head back to the rear testing the wire as you go. You push the needle into the wire and make sure you have a good ground on the clip end.
Tom
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Jims65cyclone
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Re: tailights

Post by Jims65cyclone »

You can also use the meter in resistance mode and test for continuity/high resistance in the wire between the switch and the tail light contact. Also check between each of those points and ground to see if you have a short in the wire to ground. If the wire is good, you should get no resistance on the first test, and infinite resistance on the second. Use/make some jumper wires to connect to the tester leads to give you the length you need to reach from one end to the other. Actually, I'd do the short to ground test at each end first, then rig up the jumper wires and do the end-to-end test IF the short to ground test passes. That will tell you if the problem is in the wire before you go to the trouble of tearing stuff apart.
Jim
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Lou's Comet
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Re: tailights

Post by Lou's Comet »

smithhe wrote:Thank you guys again for the replies, I swapped out the bulbs on her today and it still has the same problem. I checked all of the connections in the sockets and they are all very clean and nothing seems to be messed up, I’m going to get a voltage tester from my dad here soon since I don’t have one and check all the wires and connectors to narrow it down. I don’t know if this makes a difference but before this problem started happening I was blowing the fuse to the taillights about once a week for a month straight, I couldn’t find the problem and then after about the fifth fuse replacement it stopped blowing the fuse and then a month or so later this problem started happening, so I’m not sure if it could be a problem in the fuse box or what but I’m willing to bet it’s a problem in the switch, I’ll check it all once I get a tester and let you guys know what happens.
I am assuming you have the factory wiring with the fuse box attached to the headlight switch connector?

With that assumption:
Ok so your bulbs and sockets are ok. This narrows it down to the feed wire going back to tail lights or the switch

Quick easy way to narrow down if it is the wire or switch, here is picture of fuse box/ headlight switch connector

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Disconnect fuse box/connector from light switch.

Run a jumper wire from the right side of fuse (make sure good fuse is in box) to the tail light(black) feed wire, the red line I drew.

If your tail lights work, then you have a bad switch
If the fuse blows then the feed wire going back to tail lights is shorted somewhere and bad
If nothing happens, no tail lights, and fuse don't blow then the tail light feed wire is prob broken, thus bad

Lou

thrnelson
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Re: tailights

Post by thrnelson »

Does the 64 have the rubber boot that goes over the taillight housing plug like the 65's? On my 65 I have one light that if you push and wiggle the connector onto the plastic taillight housing it will work but as soon as you let go it stops. I still have not found a good solution. Similar to your problem the brake lights and turn signals work but the parking light will not. I tell you this in case all the wiring works, the bulbs are good and you still cannot find a solution.
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poboyjo65
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Re: tailights

Post by poboyjo65 »

thrnelson wrote:Does the 64 have the rubber boot that goes over the taillight housing plug like the 65's? On my 65 I have one light that if you push and wiggle the connector onto the plastic taillight housing it will work but as soon as you let go it stops. I still have not found a good solution. Similar to your problem the brake lights and turn signals work but the parking light will not. I tell you this in case all the wiring works, the bulbs are good and you still cannot find a solution.
Mine was like that, I just bought a new pigtail & wired it in & fixed it. I got it from one of the venders,maybe it was macs but I cant remember for sure.
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thrnelson
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Re: tailights

Post by thrnelson »

poboyjo65 wrote:
thrnelson wrote:Does the 64 have the rubber boot that goes over the taillight housing plug like the 65's? On my 65 I have one light that if you push and wiggle the connector onto the plastic taillight housing it will work but as soon as you let go it stops. I still have not found a good solution. Similar to your problem the brake lights and turn signals work but the parking light will not. I tell you this in case all the wiring works, the bulbs are good and you still cannot find a solution.
Mine was like that, I just bought a new pigtail & wired it in & fixed it. I got it from one of the venders,maybe it was macs but I cant remember for sure.
My problem is with new pigtails. This side did not have any wires going to it when I bought the car. I don't want to hi-jack the thread I just wanted to warn "Smithhe" that even after verifying all the wiring and the fuse that there could still be other issues. Thank you for the idea though. This is on the winter list which apparently winter starts this week based on the chance of flurries.

I really appreciate Comet Central and everybody that helps others out. I am hoping to go the meet up next year and put some faces with the names.
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smithhe
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Location: Southern Maryland

Re: tailights

Post by smithhe »

So update for everyone on this thread, I switched out the headlight switch today and I thought that would fix it but the problem with the running lights still not working on the tailights is still a problem. The brake lights still work and replaced the bulbs as well, I’m not sure what the problem could be now. If anyone has any more suggestions please let me know.
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popscomet
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Re: tailights

Post by popscomet »

have you tried using a test light with a sharp point,,to find out just how far along in the wire to the tail lights has current ??
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