1966 no stop lights, all other lights work

T

Thunderboy101

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Dec 4, 2022
Thunderbird Year
1966
1966 Tbird No Stop Lights. All Other Lights Work, Driving Lights And Turn Signal Lights.
 
Check your brake light switch. Make sure one wire has constant power..
 
1966 Tbird No Stop Lights. All Other Lights Work, Driving Lights And Turn Signal Lights.
Have you checked 12VDC at the main pump cylinder switch? You must have volts at all times in one wire. Then check voltage at the bulbs sockets when pressing the pedal, one wire should be positive. Check always with your tester in DC, positive probe at the wire an negative at ground chassis.
 
1966 Tbird No Stop Lights. All Other Lights Work, Driving Lights And Turn Signal Lights.
Welcome to the forums and thanks for becoming a VIP member. When you post, please follow the posting promps and include the 4-digit model year and a short summary of what your post is about. When you post "1966" nobody is going to know what your post is about when they look at the forum overview or see the weekly email digest. I updated your subject.

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1966 Tbird No Stop Lights. All Other Lights Work, Driving Lights And Turn Signal Lights.
Look for an electrical plug in the trunk. On my 1965 convertible it was under the top mechanism. Mine had become loose. I plugged the two ends back together, secured it with electrical tape, and no more brake light problems.
 
1966 Tbird No Stop Lights. All Other Lights Work, Driving Lights And Turn Signal Lights.
This problem can be caused by several failure points and can be tested using a VOM or test light:
1. Bad stop light circuit breaker (in the fuse panel)
Verify power on both sides of the circuit breaker.
- Since no exact replacements are available, an aftermarket 15A circuit breaker may be used that mounts outside the fuse box.

2. Bad stop light switch (on the pedal) or connector
Verify power from the circuit breaker on the green/red wire to the switch.
- If there is no power, a connection to the circuit breaker has failed.
Verify power out of the switch (with pedal depressed) on the green wire.
- If there is no power, either the switch is bad or the plastic bushing is worn out/missing.

3. Bad stop light relay (in the trunk on the rubber sequencer pad)
Verify the ground for the stop light relay.
Verify input power on the 14 ga red wire.
- It should be 12V when ever the key is on.
Verify power from the switch (with pedal depressed) on the green/white wire.
- This signal controls the relay.
Verify output power from the relay on the 14 ga green wire.
- Power in on the red and green/white with no power out indicates a bad stop light relay.
 
When these cars were young the common failure was the relay in the trunk. At 4 years old (1969) my Moms 1965 Bird had that relay fail and then again in 1973.
 
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