The 3rd brake lights used on 1989 to 1997 Thunderbirds are prone to overheating and thus causing perment damage to the light housing and bulb electrical socket. Pictured here are some of the results from overheating.

This is an example of what happens when the 921 bulbs stay on too long and overheats the lense.

The plastic on this socket has overheated to the point of melting. The connector shorted and blew the 921 bulb.

This is a typical overheated socket.

The bulb still worked but the damage is clear.

This is a typical set of overheated sockets to the third brake light.

Overheated third brake light housing top and bottom views. Unless you remove the plastic/carpeted third brake light cover you will not see the damage until you blow a bulb and by then it's too late.

To correct this problem you will have to purchase either a replacement wiring harness Ford part number E9SZ-15B465-A and or new third brake light housing E9WB-13A617-AA. After replacing the damaged part or parts you will need to replace the stock 921 bulbs with lower wattage bulbs 912 bulbs. The origional equipment 921 bulb is a 17.9 watt bulb that draws 1.4 amps and produces 21 candle power while the 912 bulb is a 12.8 watt bulb that draws 1 amp and produces 12 candle power. This bulb replacement will resolve the overheating of the third brake light connector and housing.