This could be a couple things. One problem stems from the “Multi-function switch” on your steering column. This is the lever that controls your high/low beams, windshield washer, wipers, and flashers. There are approximately 20 wires that run into this switch and it is not unusual for some of them to burn out over time thus causing your headlights to flicker on and off. You can either purchase a new replacement part from Ford or get one out of a similar year Taurus (probably other models too) at the local salvage yard.

Another common problem is for the actual headlight switch to go bad. This is the switch in the dashboard that you pull out to turn your headlights on. Since the foglight switch is wired in with the headlight switch this can place more load than necessary on the headlight switch. To solve this you should replace your headlight switch if it has gone bad. Additionally, you can rewire your foglights so that you can turn them on without the headlights being on. Look below for a "How-to” on rewiring the foglights:



By Jan (pronounced"Yon") zurLippe

PROBLEM:

The MN12s route all the current for the headlights and foglights through the headlight switch in the dash. There are no separate relays to take the majority of the current straight from the battery. This can cause on overload to the wiring, and especially to the headlight off/on switch in the dash. This switch gets overloaded and causes the headlights to flicker off and on. The other exterior lights and the interior lights will still stay illuminated though. If nothing is done about it, the wiring may start to melt at the connector to the switch. The wiring in the turn signal/high beam stalk on the steering column may also overload and cause the headlights to cut off for a second or two while switching from low to high beam or vice versa. In a few cases, the wiring in the stalk has even melted.
Replacing the headlight switch in the dash or the turn signal/high beam stalk on the steering column is only a temporary fix. The underlying problem, too much current running through small guage wire, still needs to be addressed.


SOLUTION:

To address this problem, the amount of current running through the headlight wiring needs to be reduced. The easiest way to accomplish this is through the use of relays for the headlights. The relays allow the majority of the current needed to illuminate the headlights to run directly from the battery, through the relays, to the headlights. Only a small amount of current, enough to activate the relays, is then run through the headlight wiring and headlight switch in the dash.
You can either make your own harness by purchasing the relays and wiring and then splicing into the existing wiring, or you can purchase an aftermarket wiring harness, such as the one offered by Competition Limited.
Competition Limited offers wiring harnesses for all year SCs. The harness plugs directly into the factory headlight connector(s). No splicing of the factory wiring is necessary. For 1989-1993 SCs, the harness comes with a diode box that allows the low beam lights to stay on when the high beams are selected. You can also use higher watt bulbs with no adverse effect on the factory wiring.
The installation is straight forward and takes less than an hour. I highly recommend the use of this harness to all MN12 owners, whether you've experienced any problems yet or not. For more information about the Competition Limited headlight wiring harness, see the link to their web site in the "Links" section of this web site.