A Faulty Ignition Switch in a 1979 Ford F-150

Trucks just seem to last longer than cars. Take the 1979 Ford F-150. In geographical locations where rust is not a problem, there are many of these trucks still on the road. That is not to say they are trouble-free. All things mechanical will eventually wear out and break. A malfunctioning ignition switch may be a quirk you are willing to endure for awhile, but eventually it may leave you stranded. Replacing the switch -- which as of 2012 is still readily available -- proactively will keep your truck going.

Ignition Switch Problems

Many 1979-vintage Ford half-ton trucks may still be in drivable condition with the original, factory-installed ignition switch. As reliable as they are, the ignition switch in these old trucks may start giving you trouble as time wears on. The switch may loosen up with age as the spring weakens, causing poor electrical contacts that may leave you unable to start the engine. Symptoms leading up to this problem may be that you have a jiggle the key to the get the switch to turn to the accessory, on or start positions. If not corrected, eventually you may not be able to turn the key at all. A worn lock cylinder in the switch may make it difficult for you to insert or remove the key from the switch.

Ignition Cylinder

The lock cylinder is the part of the ignition switch that is the most visible to you when sitting in the drivers seat of your truck. Complete replacement of the ignition switch may not be needed if the key is loose when inserted into the switch or hard to turn, but the switch works fine otherwise. Also, replacing the ignition cylinder is perhaps the easiest way for an owner to re-key the ignition switch of one of these trucks. Even if you decide to replace the entire switch, you will still need to remove the cylinder first. This is best done while the present key is still workable. Do not wait until the key will not turn at all or ends up getting broken off in the cylinder, or you will have to drill out the cylinder or have a locksmith replace it for you. The cylinder can be removed easily by inserting and turning the key to the accessory position. A straightened paper clip can then be inserted into the small hole just above the key slot. When the paper clip is pushed in until spring resistance is felt, the key and cylinder should slide right out of the switch.

Ignition Switch

The ignition switch is mostly hidden from view when sitting in the drivers seat. A metal trim bezel that has three slots in its face surrounds the lock cylinder. The bezel is threaded onto the front of the switch and attaches it to the dashboard. Removing the switch for replacement is not too difficult. Since the ignition switch is an part of the electrical system of your truck, the negative battery cable should be loosened and removed from the negative battery terminal under the hood. The wiring connector on the back of the switch can be removed by pulling out on the tabs, then pulling the connector straight out of the back of the switch. Your first instinct may be to place the blade of a flat-blade screwdriver into on of the slots of the bezel, then hitting the handle of the screwdriver to loosen and remove the bezel. While this may work, you will probable end up damaging the bezel. By pushing in on the back of the switch and twisting it approximately 1/8-turn counterclockwise, you are taking the pressure off the bezel and it can then be removed by hand with no damage. Once the bezel is removed, the switch can be removed from the backside of the dashboard.

No Key

You may have acquired an 1979 F-150 for parts or restoration that does not have an ignition key, or you may have lost the keys to your truck. You can call a mobile locksmith, who should be able to install a new ignition cylinder -- which comes with two new keys -- in just a few minutes. Since locksmiths do not come cheap, you may want to save money by drilling out the lock cylinder. This can be done using some titanium bits in your present electric drill. Starting with a smaller hole will make is easier to drill out a hole at least 3/8 in diameter in the face of the lock cylinder, which should be large enough to insert a hooked tool to fish out the small lock bar. Once this is done, the switch can be turned without a key to the accessory position and slid out of the switch. You make have to replace the entire switch if it was damaged during the drilling process.