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Horn Issue
I wanted to share this with everyone in case some one has a similar problem.
My horn on my 2003 Sienna became intermittent after 171K miles. It seemed to be positional and would work on a turn, but not if the wheel was straight. I thought it was the clock spring (spiral cable) because of the positional nature of the problem, but it turns out that it was a dirty caged bearing in the steering column. In retrospect, I should have known it was not the clock spring because a check engine code was not being thrown relating to the airbag and the cruise control worked. If your horn doesn't work and the other gizmos attached to the steering wheel do work, you might have a dirty bearing too. These procedures apply to the 2003 and probably 2002 too. I believe the 2001 and earlier models have a different configuration of clock springs and switches, so I don't know that these procedures will help you out.
The repair is fairly simple, but you need some torx drivers and a steering wheel/gear puller. Park the van and point the steering wheel straight ahead. Disconnect both battery terminals. Then wait a few minutes. This is so the airbag doesn't deploy when you're trying to remove it so this step is a critical safety step. Next remove the small round cover forward of the cruise control lever. Remove the cover on the radio controls. There is a small torx screw holding the control in. Remove it and unclip the wires going to the radio controls. You wills see two torx bolts you have to loosen under these areas that you have just opened up. Neither comes out all the way, but you have to back them out of the bracket to which the airbag is fastened. Once you get them loosened all the way, the airbag module pulls off. This can be a little tricky, so take your time and make sure the torx bolts are loosened all the way. Do not yank on the airbag once you get it loose. There is a wire on it that needs to be disconnected. There are some youtube videos on this process, but there is a spring clip that pulls back and the connector comes out. Set the airbag aside. They say to set it with the deployment side facing up. Best to put it somewhere it wont hurt someone if it goes off.
Now you should be facing the innards of the steering wheel. There is a 19mm bolt holding the steering wheel on. There is a white clip at 12 o'clock (assuming you pointed your wheels straight ahead). You need to disconnect the white clip. I did this by putting a small screwdriver on the locking tab and pushing gently up. It took almost no pressure to get this to come loose, so take it easy. Once you get the clip off, remove the 19mm nut. Mark the relative position of the steering wheel to the shaft with a paint pen or similar so that you can put the steering wheel back on in the correct position. Now you need the puller. I used a HF puller which had the right sized bolts for the two threaded holes in the steering wheel for this purpose. Once the wheel breaks free of the spline shaft, remove it carefully and be careful to not damage any of the wires that run through the steering wheel.
With the steering wheel off, you are looking at two phillips head screws holding on the cowling around the tilt mechanism. They have to come out as does the one on the bottom of the cowling. The cowling comes apart in two pieces. It needs to be removed.
With the cowling off. you are looking at the clock spring. It is held on by 4 phillips head screws. Before you remove them, tape the moving part of the clock spring to the part that does not move so that you can reinstall it without having to recenter the clock spring. If you don't do this right, you run the risk of breaking the clock spring (which is really a cable) which controls your airbag, horn, cruise control and radio controls. When you put it back in, you have to get it right, so take the time to tape it so that it does not move. There are two additional connectors at the base of the clock spring. You can remove them now if you can get to the connectors off or you can remove them once you unscrew the clock spring. The yellow one is for the airbag and it has a fancy spring clip again. By squeezing it and pushing downward the clip released. The black clip was just a regular connector.
With the clockspring taped and off, you are looking at the turn signal and wiper switch assembly. Three phillips head screws hold this in. Two are at about 11 and 1 o'clock. There is one down around 5 or 6 o'clock as well. You just have to remove these three screws and the electrical connectors to this switch assembly.
With all that removed, you are looking at the caged bearing that caused me my problem. I can't explain it, but I'm assuming that dirt and crud gets into the grease and kills its continuity to the ground so that when you press down on the horn, you're not completing the ground circuit and causing the horn to sound. I cleaned as much grease from the bearing as I could using a sharpened small dowel and a paper towel. Then I sprayed the bearing with Deoxit, temporarily put the steering wheel back on the shaft and rocked the wheel about 1/2" in each direction. I removed the wheel and repeated the process a few times. I also cleaned the spline shaft for the steering wheel, but with that big nut making contact between the shaft and the wheel, I can't imagine that it was the problem.
Assembly is basically the reverse. So long as you don't move the rotation of the clock spring and you did not turn your tires, it should go back together pretty straight forwardly. There is a torque requirement for every bolt and nut, but I don't know what they are off the top of my head. You will have to look these up. When you're done, if your horn, cruise and radio controls work AND you do not now have the check engine light on you should be good. If your check engine light comes on, you probably damaged that circuit and need professional help. If the CEL is on, you likely don't have an airbag. There is danger involved with this repair, so don't undertake it lightly without knowing the consequence of doing it wrong.
If you are fairly mechanically inclined, this isn't a bad job if you take your time and have the right tools. Any repair dealing with the airbag is dangerous and you obviously shouldn't try it if you don't know what you're doing. Doing it wrong could result in damage to your car and the airbag not deploying in a crash. If you are not mechanically inclined, don't have the tools or whatever, and you have a horn problem and your cruise control and radio controls are working (and the CEL is not on due to a air bag code), at least you know that you probably don't need the $200 clock spring the dealer might try to sell you and probably need only to have the bearing cleaned to restore your horn.
Last edited by ashcoal2000; 10-12-2011 at 04:53 PM.
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