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Submitted By: blue85prspctr
Date: February 10, 2009, 09:42:21 AM
Views: 5319
Turn Signal Fix - Doug P (blue85prspctr)
To get at the mechanism that operates the turn signals you need to remove the steering wheel and the locking plate (the thing which locks the steering wheel when the ignition key is removed). Steering wheel removal is pretty straightforward, although I did have to destructively modify the rubber innards behind the horn switch to get the steering wheel puller in position.
Removing the locking plate is more interesting. You'll need a small screwdriver and strong fingers (or the special tool). The plate is held onto the steering shaft with a wire spring acting as a lock ring which rests in a groove cut around the shaft.
Push down on the perimeter of the lock plate straight out from the opening in the spring lock. With the other hand, or a helper's hand, work the screwdriver under one end of the spring. By working around the shaft this way the spring can be removed. Keep one hand on the lock plate at all times! In fact, it would be a good idea to wear goggles. The spring behind the lock plate is VERY strong and parts may go flying if you're not careful.
With the steering wheel and locking plate removed the turn signal mechanism is exposed.
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Referring to Fig. 1, the switch assembly pivot point (red) is the axis of rotation for the white nylon switch assembly. When you engage the left turn signal this whole piece rotates counter clockwise which in turn moves the left canceling arm into the path of the canceling cams (yellow). The assembly is held in this position by a detent at the bottom, unseen in this picture.
As the wheel is turned (left) the canceling cams, which are on the underside of the retaining plate, pass by the canceling arm but do not cancel the signal, the arm is merely pushed out of the way as the cam goes by. When the wheel is returned to center, the cam comes at the arm from the opposite direction and pushing against it, forces the detent and a spring returns the arm assembly to its neutral position.
The conclusion I came to was that the canceling arm had lost its springiness and did not project far enough into the path of the canceling cam.
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I cured this with a screw as shown in Fig. 2. The white arc is the actual edge of the switch assembly in my truck. I used a half inch #6 self-tapping flat-pointed sheet metal screw (blue) so it would cut some threads into the plastic of the switch assembly and so hold itself in position against vibration. With a slightly undersized drill bit I put a hole straight through the rim of the assembly, aligning it so the screw would push on the canceling arm. I removed the switch assembly from the vehicle for this operation, although with a good eye and a steady hand it might not be necessary.
To allow adjustment after the switch assembly and locking plate are reinstalled, I drilled an access hole (gray) in the shell surrounding the turn signal innards.
Turn the adjustment screw in 'til it just touches the canceling arm. Reinstall the switch assembly, retaining plate, and locking plate.
Put the steering wheel onto the splines enough to turn the front wheels. Set the turn signal and turn the steering wheel one half turn in the direction required for the canceller you're trying to correct, then turn it back. If the signal doesn't cancel, turn the adjustment screw in one quarter to one half turn and repeat. It only took two or three tries with mine to get the signal to cancel.
Once the signal reliably cancels, the steering wheel can be reinstalled.
Date: February 10, 2009, 09:42:21 AM
Views: 5319
Turn Signal Fix - Doug P (blue85prspctr)
To get at the mechanism that operates the turn signals you need to remove the steering wheel and the locking plate (the thing which locks the steering wheel when the ignition key is removed). Steering wheel removal is pretty straightforward, although I did have to destructively modify the rubber innards behind the horn switch to get the steering wheel puller in position.
Removing the locking plate is more interesting. You'll need a small screwdriver and strong fingers (or the special tool). The plate is held onto the steering shaft with a wire spring acting as a lock ring which rests in a groove cut around the shaft.
Push down on the perimeter of the lock plate straight out from the opening in the spring lock. With the other hand, or a helper's hand, work the screwdriver under one end of the spring. By working around the shaft this way the spring can be removed. Keep one hand on the lock plate at all times! In fact, it would be a good idea to wear goggles. The spring behind the lock plate is VERY strong and parts may go flying if you're not careful.
With the steering wheel and locking plate removed the turn signal mechanism is exposed.
Referring to Fig. 1, the switch assembly pivot point (red) is the axis of rotation for the white nylon switch assembly. When you engage the left turn signal this whole piece rotates counter clockwise which in turn moves the left canceling arm into the path of the canceling cams (yellow). The assembly is held in this position by a detent at the bottom, unseen in this picture.
As the wheel is turned (left) the canceling cams, which are on the underside of the retaining plate, pass by the canceling arm but do not cancel the signal, the arm is merely pushed out of the way as the cam goes by. When the wheel is returned to center, the cam comes at the arm from the opposite direction and pushing against it, forces the detent and a spring returns the arm assembly to its neutral position.
The conclusion I came to was that the canceling arm had lost its springiness and did not project far enough into the path of the canceling cam.
I cured this with a screw as shown in Fig. 2. The white arc is the actual edge of the switch assembly in my truck. I used a half inch #6 self-tapping flat-pointed sheet metal screw (blue) so it would cut some threads into the plastic of the switch assembly and so hold itself in position against vibration. With a slightly undersized drill bit I put a hole straight through the rim of the assembly, aligning it so the screw would push on the canceling arm. I removed the switch assembly from the vehicle for this operation, although with a good eye and a steady hand it might not be necessary.
To allow adjustment after the switch assembly and locking plate are reinstalled, I drilled an access hole (gray) in the shell surrounding the turn signal innards.
Turn the adjustment screw in 'til it just touches the canceling arm. Reinstall the switch assembly, retaining plate, and locking plate.
Put the steering wheel onto the splines enough to turn the front wheels. Set the turn signal and turn the steering wheel one half turn in the direction required for the canceller you're trying to correct, then turn it back. If the signal doesn't cancel, turn the adjustment screw in one quarter to one half turn and repeat. It only took two or three tries with mine to get the signal to cancel.
Once the signal reliably cancels, the steering wheel can be reinstalled.
