Garmin Power Cord

 

I took apart the Garmin cigarette power cord by cut the cord end, then re-wired it behind the dash for that cleaner look without having to see that bulky cigarette plug into the lighter when in use. On the dashboard mounted a power female plug/LED so I can connect to the Garmin GPS. I wanted a coil wire so decided to cut a cord off a regular Motorola cigarette cord with a mini usb on the other end. Upon testing the connect to uncover the Garmin GPS goes into the computer mode instead of charge mode. Do anyone know the reason for this? I know there is a small resistor inside the mini usb wiring schema but not sure what this actually do. I know the female plug put out 5V which is what the GPS requires. Appreciate any advises on this. Thank you!

The Resistance is what puts it in Charge/Naviagate mode

It is that resistor in the Garmin mini-USB plug that triggers it to go into navigation/charge mode. There are several threads discussing this, a couple of which are:

http://www.poi-factory.com/node/11120

http://www.poi-factory.com/node/10701

You could splice the Garmin plug onto the end of the coiled wire, using heat shrink to make it look neat.

17k Ohm resistor needed

There is a 17k-ohm resistor tied between ground and the normally unused pin of the mini-USB connector. This is how the Garmin detects if you are using a Garmin auto charger. Generic chargers will charge, but the Garmin will go into disk mode rather than navigation mode.

PT

--
Garmin nüvi 200 (my first GPS), 780, & 3700 Series. And a Mac user.

try this it might help

--
etrex vista, Nuvi 350, Nuvi 650, Nuvi 750(3)

Which Port?

Did you plug it into the back or the side port? If you have a 350 it might work if you plug it into the back with the suction cup holder. I know mine is like that.

.

PaulATL wrote:

If you have a 350 it might work if you plug it into the back with the suction cup holder.

It is true that it doesn't check for the resistor in this case - it assumes it's a Garmin charger (ie capable of supplying 1A). If it's not - and the Nüvi is very discharged - you tend to get an immediate "Charge complete"...even though it isn't sad (presumably caused by the input voltage dropping, due to the excess current demand?).

--
------------------------ Phil Hornby, Stockport, England ----------------------               http://GeePeeEx.com - Garmin POI Creation made easy           »      

I found that NO resistor is needed...

Using the info from the pinouts website posted here, I wired up a connector (using the "required" resistor) into an existing Garmin AC charger whose mini-USB connector was damaged. My findings:

Using the resistor wired to pin x & pin 4 along with being connected to ground, the GPS stated that the unit was "charging". *However*, using the diagnostic mode of the unit (press the battery icon or clock icon depending on the unit for ~7 seconds), no charge was actually taking place according to the battery info displayed there.

I then rewired the connector *without* the resistor in place (simply connect pin x to pin 4 and connect that to ground) and the charger works as it should, verified by the diagnostics page along with my nuvi 350 completing a charge (displayed the "Battery charging complete" message).

Note that you need access to all 5 pins (including pin x) of the USB mini-B connector (I used some that I purchased from DigiKey). Your normal off-the-shelf USB cable with a mini-B end on it does NOT have pin x connected or wired into the cable assembly...

--
nuvi 760, nuvi 765T, nuvi 855, nuvi 3790LMT, nuvi 3490LMT - SoCal area

How about some pics?

Hey Dorkus-
How about some pics? Always interested in improving the car aesthetics.

--
“It’s their world. We’re just living in it.”

pics of what?

You want pics of the replaced connector? This replacement was done on the Garmin AC charger with the USB mini-B end...no car involved in this. mrgreen

EDIT: I noticed that the pinouts page had been updated to reflect what I said in my post above. It previously did not mention the resistor not being needed for the 500mA charging option. Sorry for being redundant.

--
nuvi 760, nuvi 765T, nuvi 855, nuvi 3790LMT, nuvi 3490LMT - SoCal area

Extra Cig Adaptor

Why not just install another cig adaptor but on the underside of the dash and plug in the Garmin cord there without cutting it? You would then have the cord still to transfer to other vehicles and no special pin connectors or ohm alterations etc..?

FYI, there is also a fuse in

FYI, there is also a fuse in the lighter tip. If you cut that off, I would recommend using an in-line fuse to protect the GPS.

Fuse in lighter adapters kind of useless I think...

bokone wrote:

FYI, there is also a fuse in the lighter tip. If you cut that off, I would recommend using an in-line fuse to protect the GPS.

I always wondered what the point of a fuse in the adpater is for and I think it is really more to protect the car's electrical system from YOU shorting something out via the lighter.

After all, how would the GPS be protected by the fuse?

If the fuse blows due to a fault then it is probably one of two things. One is that their is a short on the cable which means your GPS is already defective and is drawing too much current (or you accidentally dropped the plug end into your soda).

Or you are drawing too much current because you have too much voltage which means that the damage is probably already done to the GPS since the fuse will blow a LONG TIME (in electronics time) after the GPS circuitry has been "touched" by the high voltage.

Anyway, just some random thoughts on fuses in ciggy lighter adapters.

PT

--
Garmin nüvi 200 (my first GPS), 780, & 3700 Series. And a Mac user.

How you mount the garmin and the female plug

DorkusNimrod wrote:

You want pics of the replaced connector?

How you mount the garmin and the female plug. I understood your OP that the intent was to improve the overall appearance of how the garmin is mounted and the power connection.

--
“It’s their world. We’re just living in it.”

you're talking to the wrong poster...

e_piph_a_ny wrote:
DorkusNimrod wrote:

You want pics of the replaced connector?

How you mount the garmin and the female plug. I understood your OP that the intent was to improve the overall appearance of how the garmin is mounted and the power connection.

I think you're talking to the wrong poster. I wrote the post "I found that NO resistor is needed..." which has nothing to do with any car mounting.

--
nuvi 760, nuvi 765T, nuvi 855, nuvi 3790LMT, nuvi 3490LMT - SoCal area

wrong post

You're right. Sorry about that.

--
“It’s their world. We’re just living in it.”

Don't attempt this if you

Don't attempt this if you have one of the traffic cords. The adaptor is your receiver, as well as FM transmitter.

--
Nuvi 2595 & 760 | http://www.chucksphotospot.com

Wonder if you have pics? I

Dear DorkusNimrod..Wonder if you have pics to show how you wire without the resistor? I tried wire the ground to pinX. Garmin's battery gauge show the lighten icon which indicates to me that it is being charging. However, when I power down the unit it show the message of Charge Completed which I know the battery is not fully charge. Will this damage or reduce my battery life? By the way, anyone have a spare Garmin mini usb end for sale?

@Orca4wd See the pinouts

@Orca4wd

See the pinouts webpage already posted above:
http://pinouts.ru/GPS/garmin_nuvi_power_pinout.shtml

+5v wire from AC adapter connects to pin 1
Ground wire from AC adapter connects to pin x and pin 4 (they are soldered together). No resistor is needed between pin x and pin 4 in this AC adapter application.

--
nuvi 760, nuvi 765T, nuvi 855, nuvi 3790LMT, nuvi 3490LMT - SoCal area

Personal Observation Without Resistor in Cord

DorkusNimrod wrote:

@Orca4wd

See the pinouts webpage already posted above:
http://pinouts.ru/GPS/garmin_nuvi_power_pinout.shtml

+5v wire from AC adapter connects to pin 1
Ground wire from AC adapter connects to pin x and pin 4 (they are soldered together). No resistor is needed between pin x and pin 4 in this AC adapter application.

***********
Thanks, DorkusNimrod. Yes, without any resistor seem to work per your instruction. However, viewing the battery OS indicated the Battery Chrg ma was displaying around 8-10, versus, 210-267 ma when using the Garmin cigarette charger. Also, I notice there were some humming noises coming from the GPS unit when using the cord without the resistor. Hope this won't shorten the battery life and/or damage the GPS unit. Something to keep an eyes open...

This modification...

Note that this modification was done using a *Garmin branded AC charger* (the one that plugs into the wall outlet and lets you run/charge your nuvi inside the house).
https://buy.garmin.com/shop/shop.do?pID=1344

This was NOT done on the 12v DC vehicle power cable.
https://buy.garmin.com/shop/shop.do?pID=1371

I mentioned this in all of my posts regarding the modification.

If you are modifying the 12v DC vehicle power cable, you may need to follow another wiring procedure. Please refer to the pinouts website that has been posted.

--
nuvi 760, nuvi 765T, nuvi 855, nuvi 3790LMT, nuvi 3490LMT - SoCal area

AC or auto charger? Please clarify

DorkusNimrod wrote:

Note that this modification was done using a *Garmin branded AC charger* (the one that plugs into the wall outlet and lets you run/charge your nuvi inside the house).

Dorkus,

Perhaps you are throwing too much confusion into the discussion. The original post was about charging the unit in the car and have it NOT go into mass storage ("computer" mode) and instead operate in normal navigation mode while still charging.

You seem to be going on about simply charging the unit at home off the wall. If that is the case, then you don't need anything special at all. Just plug the unit into any old USB charger and they will likely charge fine, with or without resistors. I charge my nuvi 200 off a generic Griffin Technology wall to USB charger with a standard USB cable and it works great. But it is also in mass storage mode while charging.

So back to the original question, do any of your responses have anything to do with charging the GPS *and* navigating with the GPS while in use in the car? If so, please clarify. If not, then you are threadjacking the discussion away from the original poster's questions/need.

Cheers,
PT

--
Garmin nüvi 200 (my first GPS), 780, & 3700 Series. And a Mac user.

Confusing...

DorkusNimrod wrote:

Using the resistor wired to pin x & pin 4 along with being connected to ground, the GPS stated that the unit was "charging". *However*, using the diagnostic mode of the unit (press the battery icon or clock icon depending on the unit for ~7 seconds), no charge was actually taking place according to the battery info displayed there.

But if it's a genuine Garmin charger, connected to the Nüvi via an electrically equivalent plug arrangement, why would this be? Perhaps the resistor tolerance made it slightly out of spec?
(Also, (and off-topic!) I think it's possible that Garmin use several different resistor values, to identify other add-ons (such as the GTM 10/11 Traffic receiver and the Fleet Management interface).)

DorkusNimrod wrote:

See the pinouts webpage already posted above:
http://pinouts.ru/GPS/garmin_nuvi_power_pinout.shtml

See my post in this thread:
arrow http://www.poi-factory.com/node/10701 entitled "More bits".

I reproduced the pin designations from the official USB spec. (They are just 1-5, rather than 1,2,3,x,4).

--
------------------------ Phil Hornby, Stockport, England ----------------------               http://GeePeeEx.com - Garmin POI Creation made easy           »      

*AC Charger*

Guttermouth wrote:

Perhaps you are throwing too much confusion into the discussion.

That may be so, however re-read my first post and all others thereafter. In every post, I've stated that the modification was to the *AC charger* & never the DC car adapter until my last "This Modification" post.

The only reason for the original post was to notify others to the fact that the resistor was not needed in the particular application of modifying the *AC charger*. Nowhere did I ever mention the DC car adapter except in my last post, clarifying to the OP that it was not what I was talking about.

Confusion was also with who posted what...I never posted anything remotely related to mounting anything in the car, yet I was asked to post pictures of it.

Apologies for whatever confusion I have added to this thread and for "threadjacking" it.

Sure you can use "any old USB charger and they will likely charge fine, with or without resistors", however the mod in question with the *AC charger* is meant to replicate what the Garmin *AC charger* does when plugged into the unit...that is power the unit (in GPS mode) when plugged into it and charge the unit when the power switch on the unit is turned off.

My apologies again for trying to add some helpful info.

--
nuvi 760, nuvi 765T, nuvi 855, nuvi 3790LMT, nuvi 3490LMT - SoCal area

Won't work with transmitter cables.

cpjanda wrote:

Don't attempt this if you have one of the traffic cords. The adaptor is your receiver, as well as FM transmitter.

Very true. If your power cord is also used for traffic (i.e. the 760 and 770), this solution won't work.

Also, you can purchase a power cord with bare wires on what is normally the cigarette lighter end, so there is no need to modify the OEM one. That way, you can still transfer from vehicle to vehicle easily.

--
Mark

(why do we have to fill in a subject every time?)

DorkusNimrod wrote:

My apologies again for trying to add some helpful info.

No need to apologize for trying to be helpful. After all, that is what the group is about. But I was just pointing out that your post was a fairly different tangent than the what the original poster was asking about. While your information is good info, it really had nothing to do with the topic of this particular thread.

Sort of like if someone asked about the built in flash memory of the GPS and you replied with a series of posts about SD cards. At first blush, everyone mistakenly reads those *thinking* you are talking about the internal flash, but only after more careful reading, and a follow up to clarify, do they then realize you were talking about something very different than what was asked about.

Take care,
PT

--
Garmin nüvi 200 (my first GPS), 780, & 3700 Series. And a Mac user.

Nuvi 350 Pinouts

Not only does the power cord have a 17k resistor,
the Fleet Interface cable uses an 8.2k resistor there. This rquires power to be applied thru the back connector, with the FI cable on the side connector. The rear connector has only 4 contacts, and I don't have a cradle and have no idea what the pinout is, and whether or not the cradle has anything other than wires. Anybody know? thanks / mark

Nuvi 350 pinouts - FI cable

The 8.2k resistor provides a signal to the 350 that causes it to start dumping NMEA0183 location messages to whatever is outboard. Why? I'm putting together a datalogger using a PIC and an SD chip to record same, so I can eventually analyze my travel for business vs. personal vehicle use. /mark

Garmin Power Cord

Seems the Garmin 12V Power Cable has 3 wires to the USB Mini 'B' Eight Angle Plug.

Red (+5V), Black (GND), and White (Pin 5 or 'X' = USB Device Detection).

If you cut this White wire it stops charging and say No Cable Detected.

There is approx 20K Resistance between this White Wire and GND in the 12V Power Converter.

I conclude this 'Device Detection' Resistance is in the 12V to 5V Power Converter (Cigar lighter Plug Unit).

Since USB Mini 'B' Plugs, wired with the 5th Wire (Pin #5 or Pin 'X')are difficult to find, I figured it best to find a Male and Female connector to split the Garmin Power Cable into 2 sections so it is more versatile for Powering the Garmin Nuvi.

I was considering DC3.5 Power connector, until I learned the 17.3KOhm Resister is NOT in the USB Mini 'B', but in the 12V/5V Power Converter.

The obvious answer for compatibility and versatility. is to wire a USB 'A' Female to the cut end connecting to the 12V/5V Power Converter.

There are many 12V USB Power products available, so if the Garmin Power Unit fails, there are ready replacements with a USB 'A' Female.

To the cut end connecting the Right Angle USB Mini 'B' Plug, we can connect a USB 'A' Male .

We wont be adhering to the USB Standards, since the White Wire is wired to USB 'A' Pin 2, which is normally 'USB Data -' but connecting this should not cause any problems in USB 'A" Device connected.

The modified Garmin Power Cable, will now have a USB 'A' Female Socket' with a 20KOhm Resistor between GND, Pin #4 (Black) and 'USB Data -', Pin #2 (White). But this is a USB Power Cable so should not be connecting for DATA use.

The other end of the Garmin Power Cable with the Right Angle USB Mini 'B', will now Terminate on a USB 'A" Male plug. The only difference being that Pin #5 ('X') of the USB Mini 'B' will connect to the
'USB Data -', Pin #2 (White). I would however like to add a 1/8W or 1/4W Resistor between Pin #2 and Pin #4, so it should work in any standard USB Socket.

But what value should this resistor be?

Quote:

http://pinouts.ru/GPS/garmin_nuvi_power_pinout.shtml

Standard 5 pin mini-USB connector has pin X connect to ground (pin 4) through a 200K ohm resistor (Note: The normal USB connector has only 4 pins, the mini-USB has 5 pins). To place Nuvi into charging mode, the 200K ohm resistor must be changed to 17.3K ohm. (also successful with 22K ohm resistor from Radio Shack, also a cheap 1/8W, 5%, 15k ohm resistor will work just fine!)

I don't think the 'standard' USB Mini 'B' has any wire or Resistor connected to Pin#5 (or 'X'). But the Garmin Nuvi wants to see 200KOhm it seems.

So it works using the standard Garmin Nuvi 12 V Power Cable (modified with the USB 'A' Female Socket with a 200KOhm Resitor, I suggest a 20KOhm on the other Garmin Power cable with our modified USB 'A' Male connector, between Pin #2 (White) and Pin #4 Black #4.

So plugging that Garmin Power cable, with its modified USB Plug with the 200KOhm Resistor, into a PC or some other Power Socket, should act like the 12V Garmin Cable.

It you plug into the 'Modified' Garmin 12V Power Card with it's USB Socket, it will have a modified Resistance presented to the Garmin Nuvi.
Rt = (200x20)/(200+20)KOhm = 18.18KOhm.

According to PinOuts.ru (http://pinouts.ru/GPS/garmin_nuvi_power_pinout/), this should work fine?

Can anyone see problems with modifying the Garmin 12V Power Cable in this manner ie USB 'A' Female/Male inserted?

GTM 20

If anyone is interested in getting traffic and had the old MSN adapter you can get the GTM 20 power cord with the lifetime traffic and it will work on most of the ones that had MSN traffic (i.e. nuvi 780 etc.)

--
Legs

nuvi 2405 power cord

I cannot stand hanging cables. I want my Valentine 1 and GPS wires hidden. In my case I get power from the rear view mirror/map lights. I took apart the Nuvi cord and found a miniaturized switching power supply in the plug and a couple of toroidal somethings in the bulge in the cord. Now I have to see if I can hide everything in the mirror. Wish I could upload the photos.