1964-1966 Fender-Mounted Turn Signal Indicator Operation

 One of the cool features of the 1964-1966 series Thunderbirds is the fender-mounted turn signal indicators.  Several owners over the years have described a common problem with the operation of these lights: slow or hesitant operation usually characterized by the light coming on and not flashing, or coming on and only slightly dimming. Often, the turn indicators flash normally until you load the electrical system with headlights on, foot on the brakes, blower motor running, or any combination of these.

 To begin, the fender-mounted turn indicators will only operate with all the bulbs in the rear and lower front turn signal/parking lamp working. If they all work and the fender-mounted turn indicator does not light, there is another problem, such as the bulb in the indicator, or a relay problem in the rear. If one or both flash but no audible click is heard, check the lower front parking/turn signal bulbs. For the purpose of this article we will focus on the turn signal indicator relay located under the driver side dash.

A completely defective turn signal indicator relay is not likely since the interior location of the relay prevents corrosion from ruining the relay as often happens with the trunk and underhood relays. But the indicator relay can weaken in time, and possibly other anomalies of an older electrical system contribute to this problem as well. For one of my 66's I had purchased a new turn signal indicator relay, and replaced it. It had the same or similar problem as the original relay. I sent it back as a defective relay, and was sent another relay in exchange. It too had the same problem. I returned it for another exchange, and was instead sent a refund and no relay.

 Here's where necessity becomes the mother of invention. I had to repair my original relay to work, and here's how you can do it: Remove the far left half underdash (below the headlamp switch). The turn indicator relay is mounted with 2 hex head screws to a black metal bracket to the left of the steering column. The relay looks like most of the other metal case relays throughout the car. You will need to remove the relay from the bracket with a 3/8" box wrench due to tight clearance. Once the relay is removed and disconnected, use needle nose piers and a flat blade screwdriver to pry off the metal case from the base.

 With the metal case removed you will see a copper coil with a heavy gauge metal fixed 'arm' over the coil. You should also see a very small thin metal contact tab above the 'arm'.  Plug the relay back in, letting it hang from the dash, and now operate the turn signals to watch the movement of the thin metal contact tab. Then operate it turning on all the electrical consumers. The repair is to increase or decrease the distance between the moving contact tab and the fixed 'arm' over the copper coil.  Use a flat blade screwdriver to bend the thin contact tab up slightly. Note: this is a trial and error process and you must watch the results with each bend. Too much distance can result in a 'stutter' of the indicator lights. You must then bend the contact back down slightly. Also, make certain that the copper coil is wound tightly by twisting it with your fingers. You should be able to achieve perfect operation of the fender-mounted turn signal indicators with all the electrical consumers on, engine off. Reinstall the metal case and pinch the tuck's back with needle nose pliers, then reinstall all the items in reverse. Once the relay is back onto its bracket, try the system again before reinstalling the underdash to make certain that nothing 'changed'.

 For additional help on the turn signal system visit this website: www.thuntek.net/cougars_unlimited/tbseqts.htm

Or contact Mark Kesner at flight1966@aol.com