I am having an issue with my turn signal operation of my all stock (6 volt) 1955 Thunderbird.
I've had the car for 22 years and the turn signals worked perfectly in the past. The deterioration I'm experiencing happened over the last 2 years. It was very gradual so I didn't notice it until it became cronic.
The issue is the turn signals burn so dim that, even at night, you can barely see them. It affects the front lights, the rear lights and the dash indicators. I have collected the data on it's current operation:
The battery voltage ias 5.97 volts (motor off, ignition switch on). At the rear socket, for reference, with no bulb installed, the parking lights are 5.6 volts (both sides same). When you hit the brake light, the voltage available in socket is 5.94 volts, yielding a normal brake light (agan, both sides same). Now to the turn signal. I measured the voltage on the wire feeding the flasher and there is 5.74 volts there. To make the bulbs stay on, I put a jumper wire across the flasher, sending the 5.74 volts to the turn signal switch. When selecting either side, both left and right measure 4.1 volts. Now we know why they are dim. The interesting thing when you put the rear bulb in it's socket and watch the front turn signal or the dash indicator, the brightness drops quite a bit, indicating the voltage must fall below 4 volts when the load of the bulb is added
Some times, the flasher does flash. Other times, it does not. Nothing consistent.
Question is: Any idea what would cause both sides to have only 4.1 volts at the socket in the rear? It's not like one side is higher or lower than the other...they are almost perfect at 4.1 volts each. Have you ever experienced or heard of anyone with this issue? Can you suggest any further voltage measurements that may be useful. I have all the manuals for the car (shop and electrical) and they offer no troubleshooting help beyond what I've done. For the record, both tail lamp bulbs are correct.
I have a feeling the problem is something relatively simple.
Thanks much for your help