4th Gen Navigation Install

bensanders

bensanders

New member
For those who have installed an aftermarket Navigation HU in your runner, how did you splice into the VSS wire? I have searched the internet high and low for the location of the VSS wire and I have yet to find a consistent answer. Anybody?
 
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LargeOrangeFont said:
I did not even bother hooking it up to VSS. My JVC unit can get speed via the GPS antenna and/or VSS.
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I'm installing a JVC unit as well. From what I understand the Nav is choppy/inconsistent without the speed signal from the VSS to use in conjunction with the signal from the GPS. It can operate without the VSS connected, it's just not nearly as effective.

Have you noticed any of these issues?
 
Perchance a firmware update on that? That is obviously a software bug for the unit, considering most GPS units do not have or require access to a speed sensor. GPS signal is highly accurate to within the given error built into any car's speedometer.

Anyway. That was off topic. I would hate being told I HAD to splice into a car component for the GPS to work. That sounds like lazy programming. The GPS in my phone is highly accurate and it isn't even a exemplar design like you would see in a high quality garmin or other.

In other words... blah to forced wire mutilation!
 
DC runner said:
Perchance a firmware update on that? That is obviously a software bug for the unit, considering most GPS units do not have or require access to a speed sensor. GPS signal is highly accurate to within the given error built into any car's speedometer.
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It's not a software bug for the unit.

I'm pretty sure all OEM Navigation systems, regardless of the type of vehicle, are spliced into the VSS. Any "high-end" aftermarket Nav unit also utilizes the VSS to accurately determine positioning as you go in and out of satellite reception (driving near tall buildings, through a tunnel, deadspot, etc). It's kind of a way to help keep the satellites on track with your vehicle as they lose positioning of you throughout a trip. When you come back into reception, the satellites (or nav unit) corroborate the speed of the vehicle via VSS with the assumed speed/location of the vehicle via GPS.

Long story short, the GPS functions more smoothly and accurately when spliced into the VSS.

I could definitely forgo this step...it isn't required. However, the GPS will not function as it should and when I'm spending $700 on a new nav unit, I want it fully functional :)


Anyways...I think I've narrowed it down to the Purple/Red wire located behind the HVAC controls, but I'm still not 100% certain as to exactly which wire to use. There are apparently multiple Purple/Red wires found behind the dash and glove box. I'm pretty sure they are all VSS, but I want to make sure I'm doing the right thing before I start cutting up wires in my Runner. The search continues...
 
I can't help you as to the location... However, I CAN comment on the advantage and sometimes "necessity" of using the VSS wire for the GPS. I did a writeup on how-to add Factory Nav to my non-JBL 2010 Tundra, and the factory unit would not work properly (location) without having the VSS wire hooked up. Once I found it, it worked very smoothly. I think it was a purple wire in my Tundra as well. (DIY Just added OEM Navigation to my Non-JBL truck)

Before I did this, I was using a Pioneer Nav unit (F700bt) which didn't require tapping into the VSS wire, and it worked just fine. So, short answer is, like already stated, you probably don't need to connect it to the AFTERMARKET unit. :bigok:
 
After doing some research on the unit (JVC KW-NT30HD) and simply going by the manufacturer's recommendation I'm definitely tapping into the VSS for this install. You're pretty much reaffirming my feelings on this, thanks.
 
bensanders said:
I'm installing a JVC unit as well. From what I understand the Nav is choppy/inconsistent without the speed signal from the VSS to use in conjunction with the signal from the GPS. It can operate without the VSS connected, it's just not nearly as effective.

Have you noticed any of these issues?
Click to expand...


No issues like that at all. It works great, and the nav is smooth and consistent. I have last years model, the KW-NT3HDT.

It gave one warning when I first used the nav. It said "No VSS speed signal found" I clicked ok, and it never bothered me again about it.
 
LargeOrangeFont said:
No issues like that at all. It works great, and the nav is smooth and consistent. I have last years model, the KW-NT3HDT.

It gave one warning when I first used the nav. It said "No VSS speed signal found" I clicked ok, and it never bothered me again about it.
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Interesting...maybe I can wire everything up and take it for a test drive around the neighborhood without putting the whole dash back together, just to see if the nav works for me like it did for you.
 
Found this from another forum (same nav unit install but different vehicle, same principles):

"Ok, after initially thinking I had this solved I thought I would share a bit more on the VSS hookup. It turns out that the wire I used does indeed have the correct square wave pulse between 0 and 5 volts and is proportional to vehicle speed. The only problem is the frequency of the pulses is probably 50x what would be expected from a 4 pulse per wheel revolution signal. At about 65 mph, the pulse frequency from this wire is about 3000Hz. I think it has to do with the gear ratio at the output shaft sensor and the final drive gearing. In any case, the JVC calibrated ok at low speeds, but once I got on the freeway the frequency evidently gets too high and the unit can't correctly read the signal when the van is going over about 60 mph. I've monitored the signal with a data logger and the signal is fine - just way too fast probably for the unit. I've talked to JVC (who was actually fairly responsive) and even tried a second unit from Crutchfield (great customer service), but same thing happened. Long story short - it's probably not worth your time to try and hook up to this wire unless you know for sure your head unit can handle it. No big deal on most of the new in-dash Nav units, as the VSS is just optional and doesn't really add that much functionality. "



I am now leaning towards NOT tapping into the VSS wire. I plan on contacting JVC to see what they say.
 
Yea. The whole point I was trying to make was this: The GPS system is incredibly accurate and any added accuracy gained by adding the VSS would almost be un-needed redundant.

The VSS probably helps maintain "position" when you travel under a tunnel or some other place you would lose GPS location signal. Once you have re-established GPS signal, I don't see the VSS actually adding anything; since most cars speedo's are off by up to 10% off the factory line.


This isn't to say you shouldn't do it. You bought it and can do whatever you want, and it certainly won't decrease accuracy; I just personally consider it somewhat un-necessarily is all.
 
DC runner said:
Yea. The whole point I was trying to make was this: The GPS system is incredibly accurate and any added accuracy gained by adding the VSS would almost be un-needed redundant.

The VSS probably helps maintain "position" when you travel under a tunnel or some other place you would lose GPS location signal. Once you have re-established GPS signal, I don't see the VSS actually adding anything; since most cars speedo's are off by up to 10% off the factory line.


This isn't to say you shouldn't do it. You bought it and can do whatever you want, and it certainly won't decrease accuracy; I just personally consider it somewhat un-necessarily is all.
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Yep, I think I'll end up going with your advice. I sent JVC an email about the issue just to see what they say, I'll post that when I get a response.

I never drive through tunnels anyways, lol.
 
Sungod said:
Isn't that wire used to lock the system while moving?
Click to expand...

No, the parking brake is used for that. I purchased a parking brake relay off Amazon that will bypass this function, allowing m...my passengers.....the ability to watch DVDs and use the Nav while the vehicle is moving.

Here's the response from JVC:

"I understand you are inquiring about connecting the VSS on your JVC Mobile model KW-NT30HD.

There is no need to splice into the VSS. This unit will work rather it is connected or not; however, if you want the speed to be displayed, it must be connected."


Looks like the GPS should function normally, the unit just won't be able to display my speed...which is what my speedometer is for ;)

If the GPS seems choppy/inaccurate then I will mess with splicing into the VSS. Otherwise, I'm gonna forget it.

Thanks for the input everybody!
 
Mine displays my speed just fine without VSS connected..

It even yells at me when I got 15 MPH over the speed limit. You can adjust the MPH over the speed limit when it alerts you, or turn the feature off if you wish.
 
LargeOrangeFont said:
Mine displays my speed just fine without VSS connected..

It even yells at me when I got 15 MPH over the speed limit. You can adjust the MPH over the speed limit when it alerts you, or turn the feature off if you wish.
Click to expand...

Correct. However, the speed it is displaying is the speed calculated from the GPS, not the speed received from the vehicle via the VSS wire. I think what the JVC rep is saying is that when you splice into the VSS, the nav unit will display the true speed of the vehicle based on the vehicle's speedometer, not based on the assumed value from the GPS.

I did a little more sifting through the 2006 4Runner FSM and found what I was looking for (ECU terminal diagram) ...looks like I'll be using the VSS after all, lol.
 
bensanders said:
Correct. However, the speed it is displaying is the speed calculated from the GPS, not the speed received from the vehicle via the VSS wire. I think what the JVC rep is saying is that when you splice into the VSS, the nav unit will display the true speed of the vehicle based on the vehicle's speedometer, not based on the assumed value from the GPS.

I did a little more sifting through the 2006 4Runner FSM and found what I was looking for (ECU terminal diagram) ...looks like I'll be using the VSS after all, lol.
Click to expand...


Yea, my point what that the unit does display the speed without VSS connected. To be honest I'd trust GPS speed to be more accurate anyway provided you have a signal.
 
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