This article is one in a series that have been released in conjunction with Wayne's book, 101 Projects for Your Porsche 911. The book contains 240 pages of full color projects detailing everything from performance mods to changing your brake pads. With more than 650+ full-color glossy photos accompanying extensive step-by-step procedures, this book is required reading in any Porsche 911 owner's collection. See The Official Book Website for more details.
With many older 911s, there is a tendency for the steering column switches to become worn out. The replacement procedure for these switches is relatively easy. The hardest part in some cases, may be finding a replacement switch if you have an older car. The older turn signal and wiper switches have become increasingly difficult to find in either new or used condition.
The first step in replacing your switch is to remove your steering wheel. If the wheel has never been off of the car, then this might be the most difficult part of the job. The wheel is mounted on a spline, and fastened with a 27mm nut. To remove this nut you need a 27mm deep socket and an impact wrench.
The horn pad covers the steering wheel. On late-model cars, the horn pad simply snaps onto the wheel, and can be removed by pulling on it. On the earlier cars, the horn pad must be rotated counter clockwise in order to remove it. Hold the steering wheel in one hand and rotate the center horn pad with the other. When the horn pad is free, reach around to the back and carefully disconnect the wire that connects to the horn. Disconnect the battery before attempting this, otherwise your horn might sound repeatedly during the process.
If you don't happen to own an impact wrench, there is another neat trick that I developed for removing the steering wheel. First, take one of those obnoxiously large, red steering wheel locks and clamp it onto the steering wheel. The long handle on the lock will allow you to gain a significant amount of leverage on the wheel. Then insert the deep socket onto the nut. Compressing together the steering wheel lock handle and the long handle attached to the socket will enable you to loosen up the steering wheel nut. Under no circumstances should you ever turn the steering wheel all the way to the end of the rack and use the end stop to hold the wheel while you remove the nut. The steering wheel has a lot of leverage, and you can easily damage your rack and pinion if you apply a large amount of torque to the wheel.
Once you have the nut off of the wheel, simply pull the wheel off of the steering column. If the wheel is stuck on the splines and doesn't want to come off, then take a rubber mallet and gently tap the rear of the wheel until it begins to move.
Now, remove the black enclosures that surround the steering column. There are eight screws that need to be removed in order to gain access to the switches. Start by removing the two screws that hold on the horn contact piece. Then remove the four screws contained in the recess of the black enclosures. Finally, don't forget the two screws on either side of the enclosure. These screws can only be seen from the sides of the steering column. Once you have all eight of these screws removed, the upper and lower black surround should be able to be removed.
Once the enclosure is removed, then you should have easy access to the switches. They each can be removed by unscrewing them from the steering column. If you trace back the wires from the switches, you will easily see where they are plugged in underneath the dash. If you unplug them, the wires can be fed through the steering column.
Installation of the new switch simply involves threading the new wires through the steering column, fastening the new switch, and plugging it in underneath the dashboard. The switch comes with 2 cables, one is a simple round plug in, similar to other plug in cables under the dash. There is another round plug in just above and to the right of the headlight switch, by unplugging that round plug you get easier access to the headlight switch. There are 4 wires in the other cable , one is red and white, RT/WS, fits into socket # 75, grey and black, GR/SW, fits into socket #58L, grey and red, GR/RT hooks into a separate plug off the switch, white and black, WS/SW fits into socket # 56. I suggest testing it all before you put the steering wheel back on. When reinstalling the steering wheel, make sure that you tighten up the 27mm nut firmly, but don't use too much force. The steering wheel is not going to fall off by itself.
Sometimes, depending upon what is broken inside the switch, the individual switches can be repaired using parts from another broken one. Carefully inspect the switch for broken parts, and compare it to a new one if necessary. The switch itself can be taken apart, but make sure that you take a few photos of how it is put together before you attempt a disassembly.
While you have the steering wheel partially disassembled, you might want to replace the steering wheel bearings. This however, requires that the entire steering column assembly be removed and disassembled: not an easy job to accomplish in an afternoon.
An excellent method for removing the steering wheel involves the use of a steering wheel locking device. These locks are excellent for being able to grab onto the wheel, and they give you a tremendous amount of leverage when removing the center nut. In this configuration, simply squeeze the two levers together, and the nut should easily loosen up. Make sure that you don't turn the steering wheel until it stops and then try to remove the nut. This can most certainly damage your steering rack.
The black plastic housing underneath the steering wheel has eight screws holding it on. The two yellow arrows indicate the horn contact piece that needs to be removed. The white arrows point to the four small screws that hold the housing to the steering column (the fourth one is hidden underneath the horn contact strip). There are two more screws on each side of the plastic housing that also need to be unscrewed before the upper and lower black plastic housings can be removed.
Removing the black plastic housing shows the switches underneath. Removal of the switches is easy: they are simply bolted onto the steering column. The wires that connect them to the chassis wiring harness are threaded down into the steering column. Replacement is an easy task from here.