Accessing the back of the NAV console. & Dialing While moving!
 

Today I brought my IS250 in for its first service call, (the 5k) although it only has 3k. To make a very long story short, I had a very helpful service guy working on my car. He mentioned the override that could be perfomed on the NAV, I had known about it, and I suggested "but I still cannot dial a phone # while I am driving" even when "override" is activated. He proceeded to open up the wiring manual and we found that the pink #14 wire on the nav computer is the "spd" wire. We cut it and sure enough I could dial the phone on the screen. The downside it that the NAV became jumpy because it was only using the GPS signal as a reference.
The thought of putting it on a switch became the new option, although one was not available. I plan to do it in the near future....Flip the switch to dial on screen, then flip it back to have "smooth" navigation.
I will post pictures whenever I get around to doing it, that will include the relativly easy instructions of the removal of the whole navigation console.

good to know... though i dont like the idea of the nav being jumpy

Exactly. :eek2:

Figured out how to override DVD player in motion? :p

NICE.. i was thinking the same thing when you said that you cut it..

Same deal, he explained to me that this is the same wire to cut in the case of the GS300, so that the DVD will play when the car is in motion. He has not yet encountered a IS with DVD (or any IS for that matter), but he did suggest that it would work...I'd say it IS worth a try....

I failed to mention this becase I do not have DVD on my 250 (as much as I wish I did)!

I'm guessing this will be a very popular mod....so I will take my dash apart and take many pictures to show exactly which wire it is for everyone....

....I must go out an buy the switch before I do....

The NAV would only be jumpy when the switch (I plan to install) is in the "phone" position, as soon as Im dont dialing, I'd switch it back to "smooth" out the NAV

not a good idea to cut things like that.... :uh:

It shouldn't really hurt anything by cutting it. especially if you install a switch into it.

But thanks for the post, my installer was going to do the same thing to mine but he didn't know which wire was the speed wire.

nice find...

Actually, somebody on the 3GS forum already figured out the hack to overide the DVD player in motion, allow dialing while moving without affecting the NAV. When your dealer cut the speed wire, he cut it to both the NAV unit and the Phone/Stereo unit. He should have cut the wire to the Stereo/Phone DVD and spliced it to the Nav so you wouldn't lose precision on the NAV. You can use the touchpad based override to access the nav while driving since the mod below still won't allow you to do this (unless you want the jumpy nav)

The following link shows which wires to cut, splice and ground. Although the wire colors/connectors that he writes are for the GS...the equivalent ones on the IS are:

The parking brake wire (the one you ground) i.e. K46, pin # 23 Yellow on GS is J50 #23 RED on the IS

The Vehicle Speed into the stereo wire K46, pin # 14 purple on the GS is J50 #14 Pink on the IS

The Vehicle Speed into the NAV h1, pin # 13 is pink on GS is p1 #16 White on the IS

Just substitute these wires/pin outs in the directions below. The guy that posted below, has a installation shop in Westminister, CA, he said he do it on the GS for 150 bucks, maybe he'll charge the same on the IS. Who wants to be the first?

Everybody can buy me a beer later for spreading this info :)

https://www.clublexus.com/forums/sho...5&postcount=44

How do you get behind the nav unit?

I definetly considered that option, the only hesitation I had is that the SPD signal would be changed between the units, but since it is not, then that is also a very viable option.

PS the p1 #16 white wire in the case of MY IS250 is actually white with silver band....although the wiring diagram designates that it is white....

If you look at the wiring diagram you'll see the speed signal goes into multidisplay unit then back out and back into the nav unit. All you'd be doing is jumping the multidisplay so that a) you can watch dvd's while moving and bluetooth related functions are active while in motion. The nav unit would still receiving the speed signal so it can correct for itself.

If you have the DVD/ML option, you still need to ground the parking brake signal so you can watch dvds, doing this behind the unit will NOT affect the operation of the warning light on the dash.

Needless to say, i'll be doing this first thing next week.

Let me know how difficult it is to pop the panel off and how it all turns out. I'm probably going to do mine sometime after the holidays.

-Y