Audio Out Stereo Jack – Nuvi 55LM

I recently purchased a Garmin Nuvi 55LM GPS to replace / upgrade my current TomTom 350XL TM. The TomTom works fine but the screen has always been difficult to see in the bright sunlight while mounted on the handlebar of my CanAm Spyder. The Garmin appears to have a brighter screen than the TomTom but I have not yet used the Garmin on an actual motorcycle trip.

While being able to see the contents of the screen display, especially upcoming turns, lane changes, etc. that appear to warn / inform the driver of those events even more important is the ability to hear the voiced turn / driving directions. Very few, if any, manufacturers of GPS devices currently provide an audio out jack on their devices. That may be because it is illegal in many states to wear a headset of any type while driving. Unfortunately, when wearing a full or modular helmet coupled with traffic noise it is virtually impossible to hear the verbal instructions coming from a handlebar mounted GPS. With the purchase of the Nuvi 55LM I am again challenged by a project to add an Audio Out Stereo Jack. This will be the third GPS to which I have added the audio out jack.

It should be noted that the speakers in all GPS devices are monaural devices. Headsets are normally stereo with 3.5mm stereo (male) jacks. This means that the output of the monaural speaker of the GPS will be fed into both sides of the stereo headset in order to provide easily heard audio from the GPS. For those of we senior citizens with failing hearing in one or both ears having the monaural sound being duplicated into both ears is a real benefit!

In order to open the case of the 55LM to gain access to the speaker, and more importantly the wires to the speaker, two tools are required. The first is a torx screwdriver (of unknown size) with a miniature head. The second is a plastic tool specifically designed to separate the front of the case of the GPS case from the rear of that case. The two tools that I will be using were a part of a kit supplied with a replacement battery for my old TomTom GPS. The mini-Torx screwdriver is an absolute necessity. The plastic tool is a nice to have. A picture of the two tools used to disassemble and reassemble my GPS is included below.

IMG_1967The picture below shows the various supplies needed to complete the addition of the Audio Out Jack to the 55LM. Note the heat shrink tubing that will be used to enclose and protect the two wires to be soldered to the speaker wires and then fed out through the back of the GPS cover and then through the back of the GPS holder to the (female) stereo jack. Rubber grommets will be used to doubly protect this speaker wire as it passes through the back of the GPS case and then through the rear of the GPS holder.

IMG_1957Carefully remove the four Torx screws at each corner in the back of the GPS case. Use the plastic tool or a suitable substitute to separate the front and rear of the GPS case. Small tabs, inside, at the edges of the case hold the front and rear of the case together even when the screws are removed. There is a flat, delicate cable that connects the electronics of the front half of the case (screen) with those electronic components in the rear of the case. Be very careful not to damage that cable during handling. I inserted a piece of soft foam discarded from a cellphone case covered with a tissue on the inside between the front and rear of the GPS case to allow access to the speaker (and wires). The picture below shows the case, opened, with the foam inserted, and access to the speaker and wires shown.

IMG_1960The speaker is held in place with an adhesive ring / washer to the back of the case. Carefully remove the speaker by prying up around the edges of the speaker. Remove the adhesive washer from either the front of the speaker or from the rear of the case depending on which one it stuck to during removal of the speaker. Use this adhesive ring when replacing the speaker into the back case after soldering the leads for the audio jack to the speaker solder connections.

Note that the soldered connections of the speaker wire to the speaker are covered with some sort of black paint / insulating material. I used the tip of an Xacto knife blade to carefully scrape away this material to expose the solder points on the speaker. I then soldered the two wire leads from the speaker to connect to the stereo out jack.

A picture of the speaker with both the existing leads and the new leads soldered in place is included below. Note that great care must be used in this soldering operation to avoid loosening or damaging the existing leads while adding the new leads to the speaker. Check the soldered connections to insure quality connections. At this point a test of the GPS device speaker system to be sure the two leads from the speaker are actually providing sound to the new leads is highly recommended! Touching the male audio jack of a headset to the ends of the newly soldered leads (after turning on the GPS) while adjusting the volume of the speaker will verify that sound is coming through the newly installed leads.

IMG_1961The picture below shows where in the back of the case a hole will be drilled through which the speaker wire leads will be passed. I use a cheap soldering iron to start any hole to be drilled in either plastic or fiberglass material. The drill bit used must be sharp if a clean hole is to be achieved. Rubber grommets must also be used to protect the leads passing through the hole from damage from the sharp edges of the hole, over time. The heat shrink tubing can be installed, and shrunk at this point so that it protects as much of that wire that extends out of the GPS case as possible.

IMG_1963The picture below shows the two leads coming out of the back of the GPS case through the hole located near the bottom corner. Note the grommet in place to protect the insulation of these leads. Also note, that while not shown, a knot was placed into the two leads prior to their being passed through the hole / grommet in the back of the GPS case to prevent the possibility of accidentally pulling too hard on these audio jack wires during normal use, connecting and disconnecting the headset jack. Reassemble the back of the case to the front using the four torx screws after securing the speaker and its wire leads into their original position.

IMG_1964Locate and drill a similar hole in the corner of the GPS holder so when the GPS is mounted into the holder the leads pass through that new hole and its protective grommet. At this point the insulating, protective back part of the audio out jack should be installed onto the shrink tubing covered speaker leads. Note in the picture below the speaker leads to be soldered onto the audio out jack are shown along with the internal component of the audio out jack, out of focus!

IMG_1968The picture below shows the ground wire in place into the ground tab of the audio out jack. The left and right soldering tabs are the stereo components of the jack. Since there is only one (monaural) wire output from the GPS speaker that single wire must be attached / soldered to BOTH tabs on the stereo jack (if sound is to be fed to both ears of the motorcycle rider’s headset!)

IMG_1969To accomplish that double use of the single wire lead the exposed, braided wire is separated into two equal parts so that the wire can then be soldered to both side tabs of the the stereo jack. The picture below shows the separation of the braided wire of the speaker lead in preparation for soldering to the stereo jack’s tabs.

IMG_1970The picture below shows the stereo jack with the ground wire (black) already soldered, and with the split lead through one side of the stereo tabs on the audio jack. Tweezers were absolutely necessary for placing each of the two sides of the split lead into the holes of the soldering tabs. Once each lead is visible in the hole of the tab soldering can then permanently secure each side of the lead in place.

I know that I’ll be able to hear every instruction provided by the GPS voice!

IMG_1972The final installation picture of the stereo audio jack from the rear of the GPS holder case is shown below. I can’t wait to use this new GPS. I can only hope that in bright sunlight I will also be able to see what’s being displayed on the screen!




About justanoldguy

Retired Computer Programmer. Born and Raised in Missouri. Graduated from Missouri School of Mines in 1964. Retired in 2003. Moved to Colorado in 2010. Enjoying good health and 'front range'. Touring frequently on Can-Am Spyder motorcycle. Skiing during the Winter months at Monarch Mountain Ski Area (for free!).
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4 Responses to Audio Out Stereo Jack – Nuvi 55LM

  1. cjm says:

    why didnt you just put a chassis mount jack on the case, then the wires would not be hanging out the back

    • justanoldguy says:


      There is insufficient room to put a chassis mount jack on the case… and exactly how would you solder the wires with the case open if there were…. If you don’t have a meaningful and reasonable criticism then keep your comments to yourself!!!!!

      Just a thought.

  2. Lou says:

    Great job!
    Did you use any insulating material on the speaker connection, like paint or tape?

    • justanoldguy says:

      I was careful with my soldering of the wires to the back of the speaker. The position of the speaker in the case did not expose the soldering to any metal material. I did use a small grommet in the hole in the back of the case where the speaker wires came through to protect that wire from wear. Adding a jack to a motorcycle GPS is an absolute must in my opinion. Breaking open the case of a new GPS is a bit nerve-wracking but with care it can be done. I continue to enjoy my touring with the assistance of Ms.GPS telling me when to turn!
      Be careful out there!

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