Out of Ideas for fixing sequential turn signals. Any suggestions?

Cougar Community Classic Cougar Maintenance Restoration and Repair
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I have a '70 convertible. The sequential turn signals weren’t working, and so far I have replaced every exterior bulb and sanded/cleaned each socket. I replaced the brake light switch under the dash (the brake lights were also not working), replaced the sequential unit in the trunk, and replaced the sequential flasher can under the dash. Now I have the following: All 6 tail lights work as running lights. I now have brake lights, but only the center light on each side illuminates with the brake pedal depressed. Left and right side signals work, but only the outer light on each side illuminates. The wiring harness in the trunk looks decent, and I believe the car is completely original. I’m not sure what to do next. Any ideas? Is it possible I received a faulty sequential unit? Any suggestions would be appreciated.

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Here’s a link that might help: http://www.thuntek.net/cougars_unlimited/69seqts.htm .

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Another suggestion, clean the ground in the trunk (on the filler neck frame) and the two grounds on the core support (one behind each headlight assembly), I’ll assume your not mixing any LED lights with incandescent, your turn signals are in the side marker system and are all grounded thru the front turn signal bulb. When you turn on the left turn (no headlight or parking lights on) the inboard light and the side markers should be on, then when the second and third lights sequence then all lights go out and start over. With the parking lights on it’s the opposite, turn on, side markers go out and the inboard light in on and second and third light on when the three turn go out the side marker comes on and then the sequence starts over. If your center light is the only brake light coming on that could be a turn switch or sequence board, you say the turn signals work but only the outer light comes on, that seems a wiring problem. Unplug the sequential box and check for power (with the left turn on) on the green orange wire. If there is then plug the box back in and check for power on the same wire coming out this should be the inboard light. The turn switch feeds the box and inboard light at the same time. It is possible to have the bulbs in the wrong sockets, so check that if you haven’t yet. If you get power to the inboard bulb and the sequential box and still no correct sequence Then I would suspect the box. Remember you can not interchange LED stuff with the incandescent stuff. Just a note also if you go LED you have to change everything AND add four adapters to the side markers.

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I see you found the troubleshooting thread. Glad you are able to utilize this site to its fullest, welcome!

https://cccforum.discoursehosting.net/t/67-73-cougar-sequential-turn-signal-trouble-shooting-thread/2419/1

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Thanks very much. I’ll try this next. No LED bulbs. The inboard left turn light (in the dashboard) does not work. I assumed it was just the bulb, but does that indicate that possibly the turn switch is bad? All of the left (and right) exterior signals work, except that on the rear only the outside lights come on.

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Does your TS switch look original? If yes then it is quite older than it used to last and may very well be gone. If no, then is it connected through the connector or are the wires all connected individually? If all connections are good and in the right order I would think the TS switch is bad.

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At the sequencer are two plugs, the red plug is the input to the Sequential Circuit and the black plug is the output. Power provided to the input red plug comes from the turn signal switch and the brake light switch. Between the turn signal switch and the SEQ, are 2 plug connectors under the dash on the drivers side.

Circuit 442 powers the left inner turn signal light and also provides an input signal to the SEQ. This signal is used to internally select the left center 443 and left outer 444 taillights. Circuit 448 is also used during a left turn signal operation and it provides power for the sequencing circuits. Combined with 442, this enables the left lights to sequence.

For a right turn, Circuit 445 powers the right inner turn signal light and also provides an input signal to the SEQ. This signal is used to internally select the right center 446 and left outer 447 taillights. Circuit 449 is also used during a right turn signal operation and it provides power for the sequencing circuits.

Note 442 and 445 are solely interrupted by the flasher cans ( turn signal flasher for turn signals operations or the emergency flasher) under the dash, that is to say, the Sequencer does not output to the left inner nor right inner taillights.

You need to test the input to the sequential box to determine if your switch is bad. The red connector at the sequencer contains all of the input signals, 3 on one side and 2 on the other. The connector is as follows:

Left side of connector
448/448A Green white Left Timing Circuit
449/449A White Blue Right Timing Circuit
511 Green Brake switch input - Green

Right side of connector
Blank
445/445A Orange Blue Right switch selector
442/442A Green Orange Left switch selector


When the brakes are applied, power is applied to the following three circuits:
511
445
442

When you have the turn signal in left mode, power is applied to the following two circuits:
448
442

When you have the turn signal in right mode, power is applied to the following two circuits:
449
445

When the emergency lights are enabled, power is applied to the following four circuits:
448
442
449
445

Good Luck

Coach Jack

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Coach Jack to the rescue!! As always, good relevant info. In my circles we refer to you as the Sequential Sherpa.

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Thank you very much! Just to make sure I understand, if I turn the left signal on, I should have power to the Green/White (448) and Green/Orange (442) wires. If I turn the right signal on, I should have power in the White/Blue (449) and Orange/Blue (445) wires. Correct?

10

Farmerpete,

if I turn the left signal on, I should have power to the Green/White (448) and Green/Orange (442) wires. If I turn the right signal on, I should have power in the White/Blue (449) and Orange/Blue (445) wires. Correct?

That is correct.

Also, in your profile, you should update your location.

Good luck and et me know if you need any additional information.

Coach Jack

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Thanks very much

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Coach Jack - with the signals I’m getting power to the white wires on each side (green/white and blue/white) but no power on the orange wires on either side. Does that indicate a bad switch selector in the steering column?

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Either the switch or wiring/connection between switch & your check point. You are on the right tract, good luck.

14

FarmerPete,

Attached is a pdf file that explains how to test your turn signal switch.

Good luck and let me know if you need any additional information

Coach Jack
1970 turn signal switch wiring.pdf (185 KB)

15

Thanks again Coach. Am I correct that I have to pull the steering wheel in order to access the connection between the vehicle harness and the turn signal harness?

16

What tail lights come on when you use the 4-way flasher?