Ignition Switch Replacement

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Toyota Model: 4Runner
Petrol/Diesel: Petrol
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Intermittent starting problems can be frustrating. Over the years, electrical contacts, relays, and wiring can age and may cause occasional problems. Such was the case with our '91 4Runner. At approximately 110k miles, the starter began to operate less reliably. The starter always cranked quickly when it did work, so it seemed the battery was in good condition. A quick check of the cables also confirmed they were most likely not the problem.

Next on the suspect list was the starter itself. I thought the trouble might stem from the common problem of a worn solenoid contact, I pulled the starter and confirmed my suspicion. One of the high current contacts was badly eroded from years of starter use. Replacement of worn starter contacts is easily performed using the directions included in the link at the bottom of this page.

The starter contact replacement served us well and the 4Runner started reliably for several years. Then, at about 135k miles, it would occasionally experience starter system problems where it would not turn over. My wife swore I had it rigged to stop her from going shopping as it always seemed to happen only to her.

After doing a little more digging I found the dash key switch appeared to be acting intermittently and I could correlate the success rate of the engine cranking based on how I placed pressure on the key as I turned it.

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Replacement ignition switch. Key tumbler and cover.

There are two sections to the ignition switch assembly. The front portion is the key tumbler lock mechanism and the rear portion is the electrical switch part. I found the electrical switch is readily available through most auto parts stores, though it may need to be ordered from the warehouse. The ignition switch and small harness also include a small plunger switch that is used to sense when the key is in the tumbler. This drives the little warning buzzer when you open the door with the key left in the ignition. Replacing the switch is fairly straight forward. Here is how I did it.

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Removal of the lower dash panel. Removal of bolts securing column. Column dropped for access.

I first pulled off the small plastic cover over the key tumbler in the dash. I then removed the four phillips screws and one bolt securing the lower dash panel under the steering column. Next, I removed the two nuts and three bolts securing the steering column to the dash frame. This allowed me to drop the column down, providing access to the electrical ignition switch behind the key tumbler assembly. Be careful not to put undue strain on any wires running under the column.

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Removal of key sense switch. Removing switch assembly screw. Switch assembly installation. Installing key sense switch.

Two screws secure the key sense switch to the housing that holds the key tumbler and ignition switch. I removed these and the one screw in the back that secures the ignition switch body. Finally, I unplugged the 8-conductor connector at the wiring harness. Installation of the new ignition switch goes in reverse order of removal, as does the dash reassembly.

Source:http://www.4x4wire.com/toyota/maintenance/ignition_switch/