67-73 Cougar Sequential Turn Signal Trouble Shooting Thread

Not a day goes by that someone does not call me with technical questions regarding Cougar / Shelby / Thunderbird sequential systems. Many are easy to figure out on the phone but often I deffer to Victor Yarberry in Albuquerque New Mexico. Vic is what I call a “Lifer” when it comes to Cougars. He has always had several, knows them inside out and is the guy who developed all the solid state turn signal parts we carry. He knows every inch of these systems and is the foremost leading authority on them in the world, no exaggeration… I would like this thread to be a “Sticky” and before long every known problem that can occur with these systems will have been covered here. I suggest if someone starts a new thread elsewhere we steer them here every time. So fire away with your questions! My first question (and I know the answer) why do my 1967 turn signal indication arrows on my dash only blink three times and then dimly “pulsate” after that? Is there a solid state fix coming down the pike soon?

What about some kind of a checklist for what to do before asking any turn signal questions - that covers all the basic stuff you need to have in place before any real trouble shooting can even begin. that should help reduce repetitive queries when you can say see post # 1 item 10…etc. Cool idea Don, and way overdue! maybe we could all work on organizing that and perfecting it - then stickey it?

I have tail lights turn lights,but no brake and hazard lights.new switch and all.have no power going to brake light switch,but all fuses are good,the only one that seems to have no power is the little 5amp one.dont know where to begin

A thread like this should have a direct link to -----> Victor Yarberry’s Sequential Turn Signal Troubleshooting Guides

Where is the solid state relay located and what needs to taken apart to swap it out on a 1969 Cougar. Mine work but I do have the solid state part bought from WCCC and would mind swapping it out.

Don Rush asked “Why do my 1967 turn signal indication arrows on my dash only blink three times and then dimly “pulsate” after that?”

Thanks for the introduction and the question Don.

The 1967 and 1968 Cougar dash indicator lights are controlled by a 3-pin relay under the dash. This current
sensitive relay is calibrated to trigger when four 1157 lamps (three in the back and one in the front) turn on.
The initial flash is caused by the lamp inrush current. After the bulbs are hot, they don’t draw sufficient
current to trigger the relay again.

With age, various problems can cause this relay to “almost” trigger:

  1. Low battery charge
  2. Insufficient alternator performance (i.e. the alternator can’t keep up with that 1000W stereo you installed!)
    The factory AC 42 amp alternator can barely keep up with simultaneous headlights, turn signals, and brake lights.
    Turn the AC on, and it’s overloaded!
  3. Failing turn signal switch (excessive resistance through the contacts reduces the current)
  4. Poor turn signal switch connector pin contacts (i.e. fried or oxidized wires at the crimp points)
  5. Installation of LED lamps - they do not draw enough current to trigger the relay.
  6. Indicator Relay out-of-calibration - the metal spring that holds the contacts together stiffens
    with use from metal fatigue and becomes more difficult for the electromagnet to pull down.
    The original factory calibration usually incorrect - NOS relays typically don’t work any better!

The last problem is the most common.It is possible to recalibrate the original relays by bending
the relay contact post until the electromagnet can pull it down. The calibration depends on all
five of the issues described above - so it is tricky!

I have been developing an electronic replacement for this relay that is adjustable.
Contact me off-line at cougars_unlimited@thuntek.net if you are interested in beta-testing this new part.

The sequential control unit for a 1969-70 Cougar is located in the driver’s side trunk well,
under the trunk mat. It is inside a black box hanging on a clip.


The sequential unit is in the trunk on the DS drop-off and the flasher can is in the lower dash near the radio toward the PS footwell. Emergency flasher is on the DS in about the same place.

Check the circuit breaker that feeds the brake light circuit. It controls the power for both
the brakes and hazard lights.

That was a HUGE amount of info in just one reply. Wow! Welcome Mr. Yarberry, and I hope you stick around here for a very long time!

hey I have a 1968 Cougar and I purchased the solid state turn signal system box thing from West Coast Classic Cougar and I installed it and have been using it for about 6 months but all of the sudden i dont have break lights? I checked my brake switch and it is working properly i checked all my fuses and relays and I have power all the way up to the little black box but once it gets to that box I lose all power for my break lights. Im on a time constraint here and I dont know what to do, all the problems seem to point to that little black box. can some one help me???

The sequential system is designed so that the brake lights should pass through to the rear
lights by default. However, if both the purple and white wires are energized (which occurs
when the emergency button is depressed), the turn signals will override the brakes. If both
wires are hot, make sure the emergency button is pulled out all the way. If it is, then the
turn signal switch may have failed.

Next, pull the red connector out slightly so you can measure the voltage on the large
diameter green/white wire while the sequential unit is still plugged in. This pin should
have 12V when the brake pedal is depressed. If there is a weak connection, caused
by a bad wire, brake light switch, or connector, the voltage may drop too
low to supply the 12 amps required by the six brake lights.

Everything works except dash indicators

I guess my luck has run out. I’ve never had problem with the sequentials in the three Cougars I’ve owned. Now I do. I have the reproduction solid-state electronics in the black box and the reproduction electronic flasher - in a 1969 XR7 with tilt. Everything works except the dash indicators. They don’t illuminate at all - with turn signal nor hazard flashers, not with engine revving nor at idle, nor with engine off.

I recently had my dash apart - all the bulbs are new. Everything else on instrument panel works (well, except seat belt warning light, but I’m pretty sure that’s the relay).

Where should I start? I’m hoping I’m missing something simple, as I’m not eager to take the dash apart having just got everything put back together.

Didn’t possibly forget to put bulbs in those, did you? (I ask, because, BTDT!!! Sucks pulling it all back out again!)

That sounds like something I would do… I figure it has to be either the bulbs of a loss of continuity in the printed circuit. Either way, I think I can live without the dash indicators until I have some other reason to dig into it. I’m more interested in driving right now than taking things apart again.

I’ve had problems like that sometime in the past. Think I found either the socket contacts to the bulb or the socket contacts to the PC were not making good contact. Cleaned the PC contacts and bent them a little to increase their “spring” and bent the socket contacts to the bulb a little closer together/tighter.

I can :beerchug: to that!

Hi there,

I’m new here and I have to introduce myself with a stupid and vague question:

I recently bought the solid state turn signal kit for my 68 Cougar from WCCC. The car is currently at the shop, but the electrician thinks a plug or some wire or something is missing. The previous owner had to change some stuff because he’s German and some European countries do not allow red turn signals, therefore they had to make some changes and currently the reverse lights are the turn signals (leaving me without reverse lights, hazards and the sequential signals). I know it’s hard to make a diagnosis without seeing it, but what could possibly be missing if, like I wrote, the turn signals work, but not in the original spot.
The main harness should be okay or else nothing would work, right?

You are correct, it is very difficult to identify what is missing without seeing it. :slight_smile:
The best approach is to obtain the “Sequential Turn Signal and Emergency Flasher System” guides. There
are two: 1967 and the 1968 supplement - you will need both because there are component identification pictures
in the 1967 guide that are not found in the 1968 supplement. Then, use the guide to identify what has
been modified and put it back to factory specifications. Hopefully, the previous owner did not do any major surgery
to the wiring.

Well, I just found out he did major surgery, all the cables have been exchanged and “europeanised”, so I pretty much have to start from scratch. But that should at least make it easier for you to tell me all the stuff I need to make the turn signal unit work apart from the original main harness. I hope most of the other parts are replaced with C8WY-13A366-AS ?!