2002 Type-R Steering wheel with OEM boss

[Kaz-kzukNA1]

Hi, all.
There are lots of nice write up on similar subject so I hope I’m not duplicating too much information. However, there were not much photos on OEM steering wheel and the boss that has 9 fixing holes so I hope this will provide you with some idea.

I bought the Type-R steering boss last year (seems like long time ago…) but until recently, I couldn’t decide on the steering wheel itself due to the design, leather feeling, price and so on. As I am going to use the Type-R boss which is the modified one from Momo, I have to use the wheels from Momo or the one with the same pcd. Some of the manufactures use different pcd so please be careful.

At the end, I decided to go for the OEM 2002 Type-R steering wheel. It is based on one of the Momo steering wheel (Tuner for 02R?? Corse for 93R??) and costs about 3 times more of the original aftermarket one from Momo.

Please note that removing the SRS system from your car may affect your car insurance condition and also against the local regulation in some of the countries.
Also, you will loose the function of cruise control if you don’t create a new switch circuit after removing the SRS steering wheel.

The photo of the steering boss can be found in the post #18 of the link below;
http://www.nsxcb.co.uk/showthread.ph...2981#post52981

The photo of the steering wheel can be found in the section no.13 in post #3 of the link below;
http://www.nsxcb.co.uk/showthread.ph...7245#post57245


1. Park the car so that the steering wheel is in the straight position.

2. Remove the cable from the battery terminals.

3. Removing the SRS module
There are three TRX Star screws to be removed. Two on the left and one on the right side under the cover. You may be able to see on the photo that red thread lock being used on these screws so be careful not to damage the screw head when removing them.
Take off the left side cover first and remove the RED connector from it.
Immediately, insert this Red connector to the SRS module connector as in the photo. This is to avoid accidental trigger of SRS by static current.

Now move to the right side cover behind the cruise control set/resume switch.
Just remove the middle screw which is the only TRX one on this side.
Now you can take out the SRS module like this.

[Kaz-kzukNA1]

4. Removing the steering wheel
Disconnect the horn connector (centre, black one) and cruise control switch connector (right, yellow).
Remove the SRS connector (left, yellow) from its holder.
Ask someone to hold the steering wheel or use the impact wrench to loosen the self-lock nut at the centre of the steering wheel.

Unlike other production cars, NSX is NOT using the tapered spline so the steering wheel will just slides off from the shaft.

During this process, please do not apply any side/forward/backward force to the steering column. There is a crushable structure that allows the entire column to move forward in case of big accident. This structure could be partially damaged if you are not careful and results in entire column moving side way (left – right) with little effort. This is a quite common issue among the owners who tend to grab on the steering wheel on getting in/out of their NSX.

5. Remove the 2 screws at the driver under cover above the driver’s knee. Be careful not to loose the two rubber caps attached to the front of this cover.

6. Remove the instrument lower cover, the tilt cover and steering lower cover. Remove the clip and disconnect the Yellow SRS cable attached to the tilt cover.
The workshop manual states to remove the steering upper cover as well. This is to access the screws holding the ‘cable reel’. If you are careful, you can access them without removing the upper cover.


7. Remove the cable reel by carefully removing the screws behind the face of upper cover.

8. Keep the turn signal canceller sleeve in this position. When you fit the Type-R steering boss, these 2 metal projections will slide into the slit at the back of the boss.

[Kaz-kzukNA1]

9. On SRS steering wheel, the horn switches on both sides and the cruise control set/resume switches were connected through the cable reel. As we removed the cable reel, we need to create the connection to the contact plate at the base of the steering boss for the horn circuit. I'll leave the cruise control for the time being.

First, prepare 2 kinds of cables like these. Short one is to disable the SRS warning light and the other one is for the horn circuit. These cables will be inserted into the yellow mating connector where the cable reel was originally connected.

The length will depend on the routing of the cable.
The yellow connector is from JAE so I was lucky enough to have the exact mating pins.
The other end of the longer cable will be connected to the hand made metal part described below so attached the ring terminal.
Please insert the cables as the photo below.

Please note the orientation of the connector by looking at the position of the connector lock.
If we count the pin no. from left to right on this photo, insert the long cable at #1 and short cable at pin #4 & 6.
Use self adhesive tape to keep these pins in place.


By the way, by placing a momentary switch between pin #3 and #1 (high level) will act as the ‘SET’ function for the Cruise Control and the same scheme between pin #2 and #1 to act as ‘RESUME’ function.
I will probably add just the SET switch later at the time when I replace the steering column cover to the Type-R spec.The original lower cover for SRS steering wheel has small half moon shaped hole for the cable reel adjustment window that no longer exists.

Here is the link to the 'SET' switch installation;
http://www.nsxcb.co.uk/entry.php?141...trol-switch-01

http://www.nsxcb.co.uk/entry.php?141...trol-switch-02

[Kaz-kzukNA1]

10. Now we need to create something to establish the connection to the contact plate at the base of boss.
For this, I used the cardboard from the cereal box to use it as a template.
(I think our member Sudesh used great idea to create this circuit and he posted it on Prime in the past.)
Based on the cardboard template, I cut out the aluminium sheet and placed it like this. I used the two fixing screws originally designed to hold the cable reel.
Make sure that this hand made part doesn’t touch any of the metal part other than the contact plate at the boss. Otherwise, your horn will be continuously triggered when you re-connect the battery.
Route the long cable that was placed at pin #1 of the yellow connector above and connect the ring terminal to the hand made metal sheet with the screw as in the photo.


11. Apply good quality grease at the contact plate of the boss. This is very important as after several years, it will start to make some noise every time when you turn the steering wheel if the grease got dried out. For this reason, I didn’t use the ordinary conductive copper grease. Instead, I used race spec bearing grease. It’s not conductive so don’t apply too much.

12. Regarding the tension of arch shaped metal sheet, you just need to play with it. Not too soft but not too hard against the contact plate. It will look like this when the boss was placed in place.


13. Tighten the boss using the self-lock nut with torque wrench.

14. Put the silver ring (for horn button contact plate) on top of the boss and then the steering wheel.

15. Use three of the nine fixing holes to secure the steering wheel and push in the horn button. This button is very expensive so don’t damage it.


16. Place the black ring over the horn button and use the remaining six fixing holes to tightly secure the steering wheel to the boss.

17. Re-connect the battery cable and check the horn circuit.

18. Once you are happy with it, put back several covers that you removed during the installation.

19. As you removed the battery, you wiped out the study coefficient value of ECU. Go out for a drive and let the ECU to learn the state of engine again. Check for the centre of steering wheel and try the horn circuit again.

20. Job done.


See you all at Japfest.

Regards,
Kaz

[eclipse1501]

Great write up Kaz. My experience with the NSXR wheel is all positive and the improved feedback through the wheel reminded me just a little of my time in single seaters. Feels strangely thin at first and encourages good wheel etiquette (quarter to three) reminding you to search for those thumb "cut-outs" when cornering.

[Kaz-kzukNA1]

Just for the record.

The SRS steering wheel and cable reel weighed just over 5Kg. What a heavy wheel...


Regards,
Kaz

[mutley]

Hi Kaz,

That is perfect timing bringing up this thread, as I was wondering about how to wire in different buttons for the cruise control, and that looks so simple, by just connecting to #3 +#1 for 1 button and #2 +#1 for the other.

I have opted for a Momo wheel to go onto the NSX-R hub with the horn button on the middle and Sparco Steering wheel buttont for the cruise control.

I noticed that inside the hub there is a wire with a conector on it, I thought that may be for the horn?

Cheers

Jim

[Kaz-kzukNA1]

Hi, Jim. Good to have you back in the country.



This is the Type-R/NSX-R steering boss and the single wire is going to be connected at the back of the horn switch/button.




That wire is connected to the base of the boss that is the contact plate where the DIY spring metal piece will slide against it while the steering wheel is turned.
The spring metal is connected to the DIY long single wire from the SRS yellow connector under the steering column so it's at the high level.



Depending on the type of horn switch (single/double terminal), you will need to decide how to complete the GND circuit to activate the horn relay.




For the OEM R horn switch, it's a single terminal type so it needs another method to establish connection to the GND level when the switch is pressed.

[Kaz-kzukNA1]

For this purpose, the OEM switch is placed inside this silver ring and the outer spring of the horn switch will create continuity to the silver ring.





You can't see it in this photo but the silver ring itself is mounted directly to the boss body that is at the GND level so when the horn switch is pressed, the GND circuit is completed and it will activate the horn relay.



Cruise control is much simple.
All you need is the high signal level at the Set or Resume terminals at the Cruise Control Unit for the non-DBW model and at the ECU for the DBW one so there are many options on how and where to place the switch.
Some of the owners in Japan utilised F-matic lever to act as the Set and Resume switches.

Personally, I don't need Resume/Accel switch and only the Set one is useful so I'm thinking of installing just a black momentary switch near the half moon cut out at the left side of lower steering column cover.


Here is the link to the 'SET' switch installation;
http://www.nsxcb.co.uk/entry.php?141...trol-switch-01

http://www.nsxcb.co.uk/entry.php?141...trol-switch-02



Kaz

[mutley]

Thanks Kaz,

Excellent info as always.

Cheers

Jim