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VietVet'67 · #2 (**permalink**) 12-31-2005, 09:49 AM

"Warning"

This Modification Could 'VOID' Your Warranty!!

OK – I think I have at least one good answer to the problem of not being able to access the ‘Points of Interest’ (POI) while you are moving.

Thanks to John – ‘gpsman1’ (here) and ‘GPS man’ on the ‘Yahoo hybrid_ford_escape’ forum, for taking the time and patience to give me his answer to the problem. Plus a few others from the Yahoo forum.

The signal that the unit is using to detect motion (VSS Wire) has to be interrupted to fool the NAV into thinking you are sitting still. If you have the parts ready it should take 30 mins or less.

Let me start out in saying that there are two different ways to do the physical modification, both call for pulling the unit out. One requires cutting a wire and placing a switch in line and the other uses male and female connectors to make the splice and put the switch inline without cutting any wires.

You can remove the NAV/Radio unit using a radio removal tool that should be available at most auto parts or even WalMart. They are two (2) "U" shaped brackets with barbs on the end. Insert the "U" shaped keys into the holes as shown (push till they click into place). While pushing (pressing) the keys outward, and pulling, the unit should slide forward and out of the dash. Image of Unit with Removal Tools
Once you have the unit out, you can rest it on the shift lever so you can look at, and work on the unit. Image of Unit Resting On Shift Lever
You need to locate the VSS (Vehicle Speed Sensor) wire (gray with black stripes) that sends the speed signal to the unit. By interrupting this signal you fool the unit into thinking it is sitting still. There are about 5 different wiring harnesses going into the unit. Looking at the unit resting on the shifter the harness/plug you are looking for will be on the right front (closest to you on the right). It will be a 22 pin Black harness that has only 3 wires going into it, the gray with white stripes wire on the top right closest to you will be the VSS (Close-Up Image of harness/plug). The other 2 are a Brown/Purple and a Black/Purple. Image of Back of Unit Identifying VSS Wire
This is the wire you have to cut and splice with some 20 - 18 AWG wires long enough to reach where you will mount the switch. There are a couple of ways to do this.
If you are hesitant in cutting the VSS wire, there is a way around it. You can get the correct size male and female connectors and plug the factory female connector (the one that is currently going to the NAV unit) into a male connector attached to the lead going to the switch. Then run the other lead wire from the switch and attach a female connector to that wire and plug it into the NAV unit.
That way you will not have to cut the wire – plus if you did have to take the NAV unit back in for service, you could just unplug your wiring and plug the original factory connector back to the NAV unit. They will never know what you have done. Radio Shack sells Quick Dissconnects that should work fine.
The three wires that are going into the plug are wrapped with tape so you will have to use a sharp knife etc to cut this back far enough to leave about 1 1/2" to 2" of wire coming out of the plug before to the splice cut, plus enough room to splice the other end. It is best to use small wire nuts to secure the splice but in a clinch wrap each splice with a generous portion of electrical tape.
Route the two splice wires to where you will be mounting the switch. If you are going to place them where I did (Image of Button Placement) it is easiest to twist the wires together, for strength, and feed them from the bottom up to the opening in the dash.
For a professional installation look:
- From GPSman - You can easily press out this blank black square, (from the back forward when your radio is out) and mount a similar sized switch to the "set" button, and place it in the already die-cut hole. NO DRILLINGREQUIRED.
- You could get a replacement hole cover (on the FEH the blank one is the second from the right) and drill that to put the rocker switch in - then if you needed to have work done on the Radio/NAV you could easily replace the blank, take the wires with the male and female connectors off and replace everything just like it came from the factory.
- I put mine in an inconspicuous place on the passenger side and mounted it there. I found one at Radio Shack, a SPST Rocker Switch Model # 275-693- rectangular with small white 'ON' mark that worked and looked very good. Close-Up Image of Switch

Re-install the unit and you are done.

I had a few Reservations about doing this, but most have been alleviated by the research and road work by GPSman and my self. I was worried that doing the modification it might mess up the NAV systems instant or 15 min average EV.

Answer from GPSman : I can confirm that the break in the VSS wire DOES NOT affect your instant or average Fuel Economy. I drove around all day today with the button off, and fuel economy, both instant and average adjusted normally. (12.23.05)

After doing the modification I can concur his observations. I have driven with and without the switch on and there is ‘NO’ interruption of the instant or average FE – plus you can also access the ‘Plan’ and ‘Pan’ feature that is not grayed out. Image showing NAV with POI showing as available @ 25 miles per hour.

There is one draw back. During the time the signal is interrupted the GPS unit thinks it is in the same place that you were when you hit the switch to Off and then back On - so your displayed position will not change during this time. If you do frequent turns in the city, the system updates quickly. If you are going down a long, straight highway, the system takes a few minutes to notice you are not in the right space on the map and do a correction update.

There are a couple of things you can do to get back on track. You can by ejecting the NAV CD and re-inserting will force an immediate re-locate, plus the POI you just searched for will be in your recent places list, so you will not need to "pause" the system again, or just wait a while and it will finally get back on track.

There are quite a number of ways to mount the switch – I used the one from Radio Shack. I put lug type plugs on the end that would be going to the switch and twisted the two 18 AWG wires to give stiffness for threading them up from the passenger side of the cover. Drilled a 3/4" hole in the upper back portion of the cover and it looks great.

If anyone does this mod I would like to know how it came out. Just send me a message here - Thanks - Phillip