xviper

I've been getting some PM's of late regarding the wiring of the Yellow Box. Some people are still having problems, so I've put together this information that will hopefully outline in more detail as to how to do it and make it work.
The following is my way of doing it and is not the only way. I tap directly into the speed sensor wire at the transmission. Others have tapped into it near the ECU under the left side kick panel in the foot well. Unfortunately, this has NOT worked for some and has generated a CEL resulting in the car running like crap. The problem lies in the possible variations from one model year to another and from the final country destination.
If you look at the wiring diagram, you will see that the speed sensor wires is infiltrated or shared (either "upstream" or "downstream", I'm not sure) with other electrical systems. One of these is our Daytime Running Lights. Cutting in at the ECU may or may not work for you, HOWEVER, doing it this way is universally compatable.

First off, go here to see what the Yellow Box looks like and what it does:
http://www.blackrobotics.com/yb_home.htm

Decide where you want to the YB to live. Mine is just resting on top of the ECU just behind the kick panel where I can pull it out for making adjustments.
Now, you must jack up the car and find the Vehicle Speed Sensor (VSS) on the left side of the tranny:

It's that black thing with the wires coming out of it.
Unclip the wiring harness from the sensor. Unwrap as much of the electrical tape as you possibly can so you have a decent length of wire to work with. There are 3 wires coming out of that harness. You want to isolate the BLU/WHT one. Cut it so you have enough on each side to work with. Get a double insulated wire that has one wire striped (so you know which is which). You can use quite thin "bell type" wire as there is little current flowing through this thing. Here's what it looks like:

Connect one of the double wires to the cut wire hanging out of the VSS harness. Connect the other double wire to the cut wire going into the wire wrap that disappears out of sight. Here's a crude diagram I drew:

Once you have made secure connections, use new electrical tape to completely and securely wrap all the wires back up.
Run the double wire up and into the left side engine bay. Make a small pin hole in the rubber grommet of the large wire bundle that goes through the firewall near the top of the clutch pedal. Push the double wire through the pinhole and into the footwell inside the car.
Here, you can cut the double wire to length and make your connections with the YB. You can take power from one of the three power taps on the fuse panel using a female spade connector. Use the one that is HOT with IGNITION for best results. Here's a pic to show where those taps are. Use a voltmeter to determine which one is the desired HOT one:

Of the 3 taps, one is HOT with dash lights, one is HOT all the time, one is HOT with IGN.
Now just follow the directions with the YB to set the dipswitches for the desired correction factor. I'm running +9% with my 4.44's.

If anyone has successfully wired it at the ECU, feel free to post your instructions in this thread so people can have a choice.

honda9krpm

Could someone please post the other method as well?
I like to see if I can tap the VAFC harness for this mod as well.
I know the other way is more risky but I like to make the most of my ecu harness

Sorry xviper, no offense I hope

Prolene

The bottom most tap is hot when the ignition is on. Engine doesn't have to be running. This is what I used. Thanks, xviper for the info. Really helped.

xviper

Not in the least. In fact, I was going to invite someone to post the alternate method in this thread but forgot.
Here's a thread describing the other way:
https://www.s2ki.com/forums/showthread.php?...?threadid=74688
Check out Jenner's post about 1/2 way down the 1st page. There is also interesting info on the 2nd page too. Unfortunately, the pics are no longer available. I PM'd Jenner many times during that initial install. He was very cooperative but alas, it just didn't work for me - kept getting CEL.
"Macgyver" or "Modifry" are two other fellas you can contact.
The funny thing is, it's the same color coded wire under the dash that is at the tranny. Somehow, on some cars, by the time that wire gets to the ECU, it's not the right one. You may be luckier.

Stratocaster

You have tap the wire before it gets to the harness. It is modified beofre it gets there. Also it is not on the same harness as the VAFC would be so you still need to tap (cut) the OEM wires.

I found this out (Thanks Modifry) when I was looking at doing the same thing.

Pinky

The trick is to get the correct harness. It is the lower blue harness. I tried and tried on the ECU harness. Though it failed to work.

What DID work was getting the lower blue harness and finding the same color code wire there. Worked like a charm!!!! Modifry took a picture that explained which harness it was but I can not find it right now.

swtazn97

X: I installed the yellow box according to these instructions. NO CEL, so I think everything went well. The only problem I ran into was I thought I wasn't going to have enough slack to run the wires from underneath the steering colum to the VSS sensor underneth the chassis. Everything turned out fine though with barely enough slack.

So far i have the switches set to 0000 0000 and I haven't took the car out for a test drive (just washed my car and it started to rain).

Is this normal operation for the yellow box

Ign on/ engine start:

Yellow box blinks rapidly for a short period. Then blinks constant with sets of 8 blinks.

ie: 8 blinks, a pause, then 8 blinks... etc.

This means it's okay right, and I could drive the car like this without effecting it's default speedo calibration? I didn't install the 4.57 gears yet cuz my spring break is coming to an end, I just wanted to get the yellow box out of the way since I had time.

Thanks,

Philip D.

xviper

I had to go look it up. (You didn't really think I walk around with this sort of information in my head, did you? )
Yes, with all the switches set to "0", you have NO compensation. The description of the light blinks as you describe is correct. Once the car starts moving the flashes will stop. As long as you remain stationary, they will continue to flash in that sequence repeatedly.

swtazn97

[QUOTE]Originally posted by xviper
I had to go look it up.

GaryRudolph

Just to know I wired up my Yellow Box under the dash instead of down by the transmission. You just have to be careful enough to cut into the VSS before it T's off to the ECU and Dash.

Here's my diagram:


Again, it's very important to cut after C101, but before the T to the ECU/Dash. The T is just two wires soldered together in the wiring harness. Here's where I made my cut:


I undid the electrical tape and made the cut between those two circles.

Also, for posterity here are the Helms diagrams I used.