moparmat2000
Well-Known Member
First things first, pull the bulbs that are not lighting up, test them with an ohm meter to make sure they arent bad. You can hold them up and look for broken filaments in the bulbs but sometimes that's not ideal as the break could be in the housing itself. Testing all of them rules out bad bulbs. Replace whatevers bad. These bulbs are all common as dirt 1157 for the taillights and 1157A for the front turn signals. You will only need to buy one 2 pack of each type. That being the case I'd go ahead and just replace with new, test the old ones and keep the good ones as spares.
Next attach a second wire to the diecast gage cluster housing and run that to a body ground. The cluster wiring ground return for all the lighting was originally through the cluster mounting screws attaching it to the dash frame. This degrades over time. And at 50 years old that's father time for you. Adding a second dedicated wire ground gives you a good solid return path. Doing this may solve all the cluster lighting issues.
On newer cars if you have a bad turn signal or brake light bulb and you flip the signal lever they flash very quickly or panic flash. This let's you know you got a bulb out. On your dart it does not do this. If you have a signal bulb or brake light bulb out when you flip the signal lever the signals will blink on and off really extremely slow.
Remember that the body structure IS your ground return path for damn near everything. Your taillights and grille mounted signals have 2 wires going to them. These are for dim for running lights, and bright for signal flashing front and rear, and brake in rear. The taillights housings bolted to the body structure IS the ground return path. The fingers that clip the bulb socket into the light housing are part of the ground return path. At the front on the radiator support theres 2 ground wires attached to the radiator support. These are your return path for the grill mounted signal bulbs.
All this being said to help you get a bit smarter on electrical stuff.
1. Change out left rear exterior bulb thats not lighting, its cheap 1 pack of 1157 bulbs
2. Make sure your bulb sockets in the rear ground well to the housings
3. Make sure your ground wires at the front attaching to the upper rad support from the harness are clean. Unbolt and clean.
4. Attach a second ground wire to the back of the die cast instrument cluster housing, and run it to a good body sheetmetal ground.
5. Change out the signal flasher under the dash also cheap. Theres 2 flashers. One for signals, one for emergency flashers
Do these things and see what happens. Sometimes the problem ends up being a bad signal switch in the steering column. Pretty pricey for new at about $95, and partial column dissassembly. Try all the simple things first before looking into that.
The column switch sometimes can be a source of problems because your brakelight circuit runs through it as well. The reason for that is that when your brakelights are lit and signal is on. This allows the selected taillight to flash while the opposite taillight stays brightly lit.
Also because of this multifunction inside the switch and the taillight bulbs bright circuit doing flash or solid bright, If you ever decide to install a 3rd brakelight in order for it to operate correctly you will have to tap off the brakelight switch at the brake pedal itself and run it's own dedicated power feed wire to the 3rd brake light.
Next attach a second wire to the diecast gage cluster housing and run that to a body ground. The cluster wiring ground return for all the lighting was originally through the cluster mounting screws attaching it to the dash frame. This degrades over time. And at 50 years old that's father time for you. Adding a second dedicated wire ground gives you a good solid return path. Doing this may solve all the cluster lighting issues.
On newer cars if you have a bad turn signal or brake light bulb and you flip the signal lever they flash very quickly or panic flash. This let's you know you got a bulb out. On your dart it does not do this. If you have a signal bulb or brake light bulb out when you flip the signal lever the signals will blink on and off really extremely slow.
Remember that the body structure IS your ground return path for damn near everything. Your taillights and grille mounted signals have 2 wires going to them. These are for dim for running lights, and bright for signal flashing front and rear, and brake in rear. The taillights housings bolted to the body structure IS the ground return path. The fingers that clip the bulb socket into the light housing are part of the ground return path. At the front on the radiator support theres 2 ground wires attached to the radiator support. These are your return path for the grill mounted signal bulbs.
All this being said to help you get a bit smarter on electrical stuff.
1. Change out left rear exterior bulb thats not lighting, its cheap 1 pack of 1157 bulbs
2. Make sure your bulb sockets in the rear ground well to the housings
3. Make sure your ground wires at the front attaching to the upper rad support from the harness are clean. Unbolt and clean.
4. Attach a second ground wire to the back of the die cast instrument cluster housing, and run it to a good body sheetmetal ground.
5. Change out the signal flasher under the dash also cheap. Theres 2 flashers. One for signals, one for emergency flashers
Do these things and see what happens. Sometimes the problem ends up being a bad signal switch in the steering column. Pretty pricey for new at about $95, and partial column dissassembly. Try all the simple things first before looking into that.
The column switch sometimes can be a source of problems because your brakelight circuit runs through it as well. The reason for that is that when your brakelights are lit and signal is on. This allows the selected taillight to flash while the opposite taillight stays brightly lit.
Also because of this multifunction inside the switch and the taillight bulbs bright circuit doing flash or solid bright, If you ever decide to install a 3rd brakelight in order for it to operate correctly you will have to tap off the brakelight switch at the brake pedal itself and run it's own dedicated power feed wire to the 3rd brake light.
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