tail light circuit
#1
tail light circuit
All of a sudden yesterday my tail lights won't work. Everything else seems to work fine. No tail lights or brake lights. where is the tail light circuit on a 68 fury? The tail lights are grounded to the body obviously, so what would the most likely cause of all 4 tail lights suddenly not working. The headlights come on. the tail lights were working fine. Could this possibly be a fuse that would only effect the tail lights and brake lights? I did check the fuse box and none of the fuses appear to be blown.
Last edited by schizm12487; 03-31-2013 at 08:34 AM.
#2
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schizm12487 (03-31-2013)
#3
on the drivers side is a plastic kick panel behind there is a 6 gang connector that goes to the tail lights. The wiring runs along the drivers side under a fold over metal panel along the edge where the carpet sits.
There is a bent over tang that holds the wiring along the rear wheelhouse under the rear seat. From there it goes into the trunk. Some models also had another 6 gang connector there.
It will run up along the drivers side quarter under the trunk edge OR down along the seam of the trunk extension if there is a groove and then to the tail lights. In the middle near the trunk latch there will be a rubber groment to the license plate light.
Usually if the tail lights dont work is due to the front connecter being rotten or wires broken there or along the door edge if someone got creative with screws for sill plates.
If the car had a trailer hitch wiring at one point put in sometimes the wires in the back totally rot out.
Best bet is to check for voltage at the tail lights themselves with a voltmeter then at the front behind the kick panel. Usually limits where the problem might be. Sometimes mice love to nest behind that kick panel so be warned that it could also be mice eating out the wires too.
There is a bent over tang that holds the wiring along the rear wheelhouse under the rear seat. From there it goes into the trunk. Some models also had another 6 gang connector there.
It will run up along the drivers side quarter under the trunk edge OR down along the seam of the trunk extension if there is a groove and then to the tail lights. In the middle near the trunk latch there will be a rubber groment to the license plate light.
Usually if the tail lights dont work is due to the front connecter being rotten or wires broken there or along the door edge if someone got creative with screws for sill plates.
If the car had a trailer hitch wiring at one point put in sometimes the wires in the back totally rot out.
Best bet is to check for voltage at the tail lights themselves with a voltmeter then at the front behind the kick panel. Usually limits where the problem might be. Sometimes mice love to nest behind that kick panel so be warned that it could also be mice eating out the wires too.
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schizm12487 (03-31-2013)
#5
You haven't really said what you have/ have not checked. Could be several things, and could be more than one problem.
Do the signals work but not brake lights, or just no lights at all?
All fuses should have power on BOTH ends of the fuse with the key in accessory, EXCEPT the end "instrument" fuse. This fuse is a trick
The instrument / dash lamp fuse works like so:
The dash dimmer control gets power from the tail fuse, so that has to be good FIRST. Power goes through the switch in park or head, to and through the dimmer control, THEN down to the instrument fuse (tan) and out to all the dimmer controlled lamps on orange wiring.
So you need:
1---good grounds at the sockets
2--good connections in the sockets
3--good bulbs in the sockets
4--good tail fuse, and power at both ends of the tail fuse.
5--If you have signals but no brake lights, that part of the problem is likely right in the column signal switch. Check power in/ out of the brake light switch, the cold side of which feeds up to the TS switch
6--no dash lights, could be a bad tail switch, bad dash dimmer control, or bad fuse/ bad connection at the instrument fuse. It IS POSSIBLE that every single dash bulb is either burned out or not making connection---it HAS happened.
Do the signals work but not brake lights, or just no lights at all?
All fuses should have power on BOTH ends of the fuse with the key in accessory, EXCEPT the end "instrument" fuse. This fuse is a trick
The instrument / dash lamp fuse works like so:
The dash dimmer control gets power from the tail fuse, so that has to be good FIRST. Power goes through the switch in park or head, to and through the dimmer control, THEN down to the instrument fuse (tan) and out to all the dimmer controlled lamps on orange wiring.
So you need:
1---good grounds at the sockets
2--good connections in the sockets
3--good bulbs in the sockets
4--good tail fuse, and power at both ends of the tail fuse.
5--If you have signals but no brake lights, that part of the problem is likely right in the column signal switch. Check power in/ out of the brake light switch, the cold side of which feeds up to the TS switch
6--no dash lights, could be a bad tail switch, bad dash dimmer control, or bad fuse/ bad connection at the instrument fuse. It IS POSSIBLE that every single dash bulb is either burned out or not making connection---it HAS happened.
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schizm12487 (04-03-2013)
#6
the fuse circuit appears to be fine. There is power on both sides of the fuse. the signal lights work, and the tail lights blink with the signals and flashers. The parking lights also blink with the signals and flashers. the parking lights do not work, but the headlights do.
#7
Question? Is it a single light switch that twists from side to side for headlight dimmer control or 2 seperate switches. One a wheel on the dash for dimmer and the other a three position toggle switch. 69 had a similar switch but was more of a v type one. Contrary to the belief of others most Chrysler products up to the late 80s didn't have a fuse for lights(70s and 80s did have a place in box but wasnt used for some reason). The fuse is the switch itself but power was supplied via the battery fuse in the box. The box also had a fuse for gauges marked instrument that had no effect on lights. An easy way to tell if the main battery fuse is blown is to check if there is power to the cigarette lighter. Believe it or not a piece of metal in the lighter has knocked out power to the lights on a few cars leaving people scratching heads.
The internal fuse in the switch only blows if there is a direct short in the wiring. If your switch is no good there is usually a really good reason for it. The dimmer switch is finicky as it ages. Play with the switch with just your park lights on. If they light up its not the switch.
This is all providing nobody has played with the factory wiring in the box. In case your wondering the headlights run in a completely seperate circuit with a circuit breaker instead of a fuse.
The parking lights flashing with the rest usually means a shorted bulb, wrong bulb in socket, or a really bad ground somewhere. The hazard lights/turn signal/brake lights are not normally connected to the park light/dash/interior light. Use an aligator clip to a good ground such as the truck latch where it is worn and the outside of a bulb housing. If brake light/hazard lights blink normally and park lights work look for the bad ground. Chances are that the brake lights are using the light circuit as ground.
The internal fuse in the switch only blows if there is a direct short in the wiring. If your switch is no good there is usually a really good reason for it. The dimmer switch is finicky as it ages. Play with the switch with just your park lights on. If they light up its not the switch.
This is all providing nobody has played with the factory wiring in the box. In case your wondering the headlights run in a completely seperate circuit with a circuit breaker instead of a fuse.
the fuse circuit appears to be fine. There is power on both sides of the fuse. the signal lights work, and the tail lights blink with the signals and flashers. The parking lights also blink with the signals and flashers. the parking lights do not work, but the headlights do.
Last edited by jacilynn_s; 04-01-2013 at 12:04 PM.
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schizm12487 (04-03-2013)
#9
Found it!
Well, I found the problem. Up under the dashboard, to the left of the light switch is a single red wire with a plug. Not sure where it goes to, but apparently that wire and/or plug has a loose connection. When I moved that wire around the circuit worked again.
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schizm12487 (04-03-2013)
#11
Yes, and I am unsure if this is that same wire. It doesn't connect to the light switch though. It sits to the left of the switch and a little higher. It seems to come out of the wiring harness, but not sure where it goes to up on the left. It is a single wire with a connector. I am just glad I found the cause and resolved it without having to dismantle the whole car.
#12
If all you did is wiggle something, you haven't really fixed anything
The headlight switch has TWO power feeds
The power that runs ONLY the headlights comes directly from the under dash splice in the black ammeter wire. This is a large gauge wire and is NOT fused until it gets to the light switch, which has a breaker built in, again, only for headlights
Tail/ park and dash lights are fed from the fuse panel tail fuse.
There is only so much in these circuits, and easy to check them all. Basically the power path for tail is
fuse panel--tail fuse---headlight switch---kick panel connector--back to rear--to tail lights.
There is only so many switches, connectors, and sockets in that path. As old as these girls are, it's common for the fuse panel fuse clips to be loose/ damaged/ corroded, or the headlight switch connector to be damaged/ corroded, or of course the switch itself. You simply have to go through this step by step.
The headlight switch has TWO power feeds
The power that runs ONLY the headlights comes directly from the under dash splice in the black ammeter wire. This is a large gauge wire and is NOT fused until it gets to the light switch, which has a breaker built in, again, only for headlights
Tail/ park and dash lights are fed from the fuse panel tail fuse.
There is only so much in these circuits, and easy to check them all. Basically the power path for tail is
fuse panel--tail fuse---headlight switch---kick panel connector--back to rear--to tail lights.
There is only so many switches, connectors, and sockets in that path. As old as these girls are, it's common for the fuse panel fuse clips to be loose/ damaged/ corroded, or the headlight switch connector to be damaged/ corroded, or of course the switch itself. You simply have to go through this step by step.
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schizm12487 (04-11-2013)
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schizm12487 (04-11-2013)
#14
This problem seems to go back to the headlight switch. When I jiggle the toggle switch, it seems to make the connection and the dash lights and tail/brake lights work. I have another switch on order, awaiting delivery. Not sure why in the off position nothing works though. I can seem to make it connect in an odd position between park and headlights. Can't seem to get it to connect in any other spot.
#15
Sounds like you are on the right track, but don't just assume it's the switch. Could easily be the harness connector itself. I don't know where you are located, but to a certain extent, the terminals in the connectors are replaceable.
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schizm12487 (04-10-2013)
#16
the terminals seem to be connecting OK. the problem seems to be with the switch. jiggling it into that odd position will turn things on. I will know for sure when the new switch arrives and I install it.
#17
Just an FYI, in 1968 the front parking lights do not come on with the headlights. For some reason known only to Chryslers electrical engineers they are only on when the headlight switch is in the parking light position; turn on the headlights and the parking lights go out. Both of my '68 Chargers were that way and a friend of mines '68 Road Runner is the same way too. The side markers are on in either position. Might save you some unnecessary troubleshooting.
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schizm12487 (04-11-2013)
#18
I know the parking lights and headlights do not come on at the same time. Problem is definitely the headlight switch. I disassembled it yesterday while I am awaiting my replacement in the mail. the copper kajiggy things (brushes or contacts or whatever they are called inside the switch) are worn down and weren't making good contact. That kinda accounts for why my giggling wires in the dashboard seemed to temporarily get things working again. It must have moved the inside of the switch just enough to continue making contact temporarily.
#19
Here is the disassembled switch in case anyone is curious what they look like on the inside. I am going to try to rebuild this if I can find the copper contact jiggydoodle things. Oh, and the ball bearing that I lost.
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schizm12487 (04-11-2013)
#21
I haven't found luck with the 3 position toggle headlight switch for the C bodies. Napa and the other stores list a headlight switch for 68 plymouth fury, but it is not the correct one. The one they list has the dimmer built into it with a pull ****. I need the separate toggle switch from the wheel dimmer switch. I found one online and ordered.
#22
Hey, sorry to hijack this old Thread but i have exactly the same problem. Also a 68 Fury III. I have tried a new Headlight switch but it didnt do it, still have to wiggle it between park and headlights.
I also have no Dash/Tail/Park and indicator lights. basically the switch dosent work in the middle position.
On the Tail Fuse i have 12 Volts when I switch the switch to Park and headlights, the dimmer switch also works. When i switch to Headlights literally only the headlights come on.
I already checked all fuses and they are all good.
I measured some stuff at the Switches and Fusebox:
The dimmer switch works but when I unplug it and measure Voltage on the 3 Connectors they all have 0 Volts, regardless of Light switch Position. My 2 Light switches are fine, i measured the contacts and they all switch how they should!
Interior Lights work.
- Regardless of Ignition switch Position
Light switch in Park or Headlight Position: Tail Light Fuse has 12Volts across.
Light switch off: Tail Light Fuse has 0.4 Volts across.
however, the Instrument Fuse with the Orange/Tan wire has 0 Volts.
-Ignition switch in Accessorie Position and Lightswitch Off
All Fuses have 0 Volts across except Tail and Dome Fuse, they have 0.2 Volts
-Light switch in Park
Yellow and Pink wires on the connector have 0 Volts (That would be the Park and Dashlights circuit i guess)
When i fiddle the switch between the Park and Headlight position, i can get 12Volt to the Yellow wire on the connector.
I already took apart the connectors to the Tail light behind the Kick panel and cleaned everything, thats all good, no corrosion. But somwhere it must lose the connection to the Park/Tail/Dash Light Power!
I checked both of my lightswitches, they both switch and work fine outside the circuit so its not the switch itselfe!
I also have no Dash/Tail/Park and indicator lights. basically the switch dosent work in the middle position.
On the Tail Fuse i have 12 Volts when I switch the switch to Park and headlights, the dimmer switch also works. When i switch to Headlights literally only the headlights come on.
I already checked all fuses and they are all good.
I measured some stuff at the Switches and Fusebox:
The dimmer switch works but when I unplug it and measure Voltage on the 3 Connectors they all have 0 Volts, regardless of Light switch Position. My 2 Light switches are fine, i measured the contacts and they all switch how they should!
Interior Lights work.
- Regardless of Ignition switch Position
Light switch in Park or Headlight Position: Tail Light Fuse has 12Volts across.
Light switch off: Tail Light Fuse has 0.4 Volts across.
however, the Instrument Fuse with the Orange/Tan wire has 0 Volts.
-Ignition switch in Accessorie Position and Lightswitch Off
All Fuses have 0 Volts across except Tail and Dome Fuse, they have 0.2 Volts
-Light switch in Park
Yellow and Pink wires on the connector have 0 Volts (That would be the Park and Dashlights circuit i guess)
When i fiddle the switch between the Park and Headlight position, i can get 12Volt to the Yellow wire on the connector.
I already took apart the connectors to the Tail light behind the Kick panel and cleaned everything, thats all good, no corrosion. But somwhere it must lose the connection to the Park/Tail/Dash Light Power!
I checked both of my lightswitches, they both switch and work fine outside the circuit so its not the switch itselfe!
#23
No head lights or dash lights
hi i need help ...im rebuilding my 67 fury 3 coupe and have just installed my under bonett wireing i have no headlights or dash lights i have no power coming back into the engine bay for the lights the blinkers have power and i have the glovebox light ...do i need to have the tail light wireing hooked up to achive this ??
#24
Parts including bearing I purchased
This is where the missing bearing goes
Back together
Last edited by zmann800; 09-24-2019 at 02:46 PM.
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