Speedo/ Odometer heal for larger tires

[jLB]

The Yellow Box plug-n-play harness connects to the output of the transfer case, and that IMO is a much easier option of removing the glovebox and splicing wires. This is upstream of the engine/tranny ECU, so it thinks nothing has changed. The RPM shift points would be the same, only the speed would be different.

I had the YB PnP on my 80 and it worked very well and was simple to install.

Thanks for the input.

I get the part about the P-N-P directly off of the transfer case, and that is "upstream" of everything.

From my perspective and/or background

"Method 2's splicing"

dropping the glovebox
cutting, soldering and shrink wrapping a few wires
reinstalling the glovebox
drop the yellow box in the glovebox.​

seems a whole lot easier (and more appealing) than

"Method 1's P-N-P"

climbing under the vehicle
finding the right plug
inserting the P-N-P harness
Identifying a suitable grommet to route it back to the interior (or waterproof it find a place to mount it under the truck)
routing and zip-tie the cable
peal back the interior to find the grommet on the inside
route the cable to a suitable spot in the interior that allows initial adjustment and tucks out of the way when done.
​

Digging through the forum, I see a number of write-ups of the "splice and dice method":

Installing Generic Marks4WD speed calibrator that uses pin 6 on IX1
Installed a superlift speed sensor calibrator that uses pin 7 on IX1​

I'm just trying to wrap my head around what is "upstream"/"downstream" of these points (what systems would receive the modified signal), and do I want to modify the signal on pin 6 or pin 7...

 

[cap80]

Does the signal modification have a significant affect on the systems in question? With 33's we are looking at a change of 8% correct? How much does this really matter? I'm wondering with so many successful installs with no "noticeable" alteration to vehicle function is this really that big of a consideration. I realize the ECU's all perform a number of calculations based on the information from the vehicle and any change will affect these, but it seems that even with the corrections the ECU's don't fall beyond "normal" range or there would be more problems reported.. The responses to both installs seem to be overwhelmingly positive short of issues with earlier versions that were corrected in later iterations.

 

[sdnative]

FWIW, the YB website only shows the v4 but the v5 is what's available. The link in post 11 of this thread has some good pictures of what the v5 looks like.

Since this is a set it and forget it kind of device, I really see no reason to hassle with splicing wires or trying to route it up into the cab. But, to each their own.

Find a way to waterproof it and mount it on the underbody somewhere or route it up into the engine compartment. There are a few good ideas of waterproofing floating around. I had mine zip-tied to the slider leg outside the driver door temporarily while dialing in the proper setting, then relocated it somewhere more appropriate. I basically made an adjustment, drove for a bit comparing speedo to gps, stopped and opened door to make a slight adjustment, then drove again. Only took 2-3 of these cycles to dial it in perfect

 

[jLB]

I'm really not asking "do they work?", "are they worth the money?", "has one ever been installed on a 100 series?", or "which one is best?". I've already ordered a "correction box" (YellowBox) for my kid's car.

I understand the concept for the box, it is pretty darned simple, the connections are +12VDC, ground, input frequency, output frequency. Its function is that it reads the input frequency and outputs a frequency adjusted by a programmable multiplier.

I understand that there are 2 schools of thought when installing these types of boxes in our vehicles:
1) install at the source of the signal (transfer case) and send a modified signal to the entire vehicle.
2) install at IX1 pin 6 or 7 (it appears pin 7 is appropriate for my son's 2000 according to the EWD) which appears to be just the signal to the "Combo Meter"

Looking at the 2 install processes, I have a mild preference for installing at IX1.

As I stated earlier, my primary interest is correcting the speedometer reading on my son's vehicle, as he doesn't seem to have an aptitude to do the math in his head. I don't think the "but officer some guy on mud said 8% wasn't really a big deal" is gonna work real well for him.

I understand that you might get a cruise control that thinks it's going 65, when it is really going 70.2, in fact if it avoids the surging issue mentioned earlier in this same thread, that might be a good thing. Who really cares the number that the cruise control sees as long as it works. There are other systems that fall into that same category.

My question is directed more at for those that opted for the install at IX1. Have you found any drawbacks to this installation method? Is there something that I am overlooking? Should I quit fighting it and deal with the output at the transfer case?

 

[jLB]

I installed my son's YellowBox in his 2000 TLC over the weekend, using the "behind the glovebox" method.

The install was a breeze.

Drop the glovebox.

Insert the YellowBox in the wire connected to IX1 pin 7 (this seems to vary based on year model, on a 2000 it was pin 7, other write-ups show pin 6). Input away from the connector, output toward the IX1 connector, a little solder and shrink tube and it's done.

Tap into power from the antenna relay connector A30 (pin 7) 12VDC and (pin 5) ground, with a pair of red scotchloks.

Reinstall glovebox.

This method seems to send a modified signal to the speedometer and the trip odometer (possibly the odometer, but haven't proven that yet) everything else in the vehicle seems to receive an unmodified signal.

This was so easy, I may have to install one in my LX too.

 

[Mike6158]

The Yellow Box plug-n-play harness connects to the output of the transfer case, and that IMO is a much easier option of removing the glovebox and splicing wires.

I just opened my "plug and play" package and it has a wire with a plug on one end and stripped wires on the other. So I went to their site and looked at the install instructions. It says to see their specific install instructions for my vehicle but there aren't any. Then I noticed that their instructions are for the V4 yellow box. I have a V5 yellow box.

Edit- Oops... There were two packages... Still no installation instructions but it is a plug and play harness so I don't anticipate any problems

 

[Thunder90]

I just installed mine today. It is also the V5 w pnp harness. Forget all the instructions and calculation crap that came with it. I installed mine in less than 10 minutes.

Plugs it in to the transaxle and route over to DS drain plug. Take out drain plug, push up through floor. Remove DS kick plate, pop up door sill trim and peel back carpet a bit to expose drain plug.
Replace drain plug over wire. It's tight but works. You will have about a foot of wire w the box in footwell.
Start up, and calibrate box.
For my 33s I punched in 7% on the GREEN button. That means press and hold for 7x flashes after putting in calibrate mode. Tuck back behind kick plate. Restart. Done.
No splice, no mount.

 

[Mike6158]

I just installed mine today. It is also the V5 w pnp harness. Forget all the instructions and calculation crap that came with it. I installed mine in less than 10 minutes.

Plugs it in to the transaxle and route over to DS drain plug. Take out drain plug, push up through floor. Remove DS kick plate, pop up door sill trim and peel back carpet a bit to expose drain plug.
Replace drain plug over wire. It's tight but works. You will have about a foot of wire w the box in footwell.
Start up, and calibrate box.
For my 33s I punched in 7% on the GREEN button. That means press and hold for 7x flashes after putting in calibrate mode. Tuck back behind kick plate. Restart. Done.
No splice, no mount.

Excellent. I just corrected my post. The harness was in a separate package that had slid behind some "stuff".

 

[jbuswim]

Just did the yellow box this weekend. Easy to plug in. After some driving and fine tuning the wiring felt a little soft from the heat. Still need a more permanent solution to secure it than what I have now. But it was a cake install and totally worth it for me.