SkyView GPS-2020 Connector Wiring Completed

At this point in time all the connectors and wiring harnesses have been installed except for the wiring harness for the Dynon SkyView GPS-2020. The GPS-2020 wiring harness is made up of a very long, four wire, twisted cable with no connector pins on the ends of the wires. This unit was purchased directly from Dynon because Van’s is still testing and readying the avionics package to include the new GPS-2020 unit. Not wanting to wait any longer, I made the purchase directly from Dynon after hearing they had tested the new GPS-2020 receiver in the RV-12 and it performed well without any adverse issues. So not sure if the one supplied by Van’s will have shorter wires with connector pins already attached, but the unit from Dynon did not.

There is a package of connector parts that is RV-12 specific which contains the male pins, DB-9 connector body, strain relief, mounting screws and the clam shell with a GPS label.


The wires were measured leaving a little excess, cut, then stripped. The four wires go into a DB-9 connector and required crimping male connector pins on the ends of the four wires.

Crimping a male connector pin onto the end of one of the wires coming from the Dynon SkyView GPS-2020 module.

The plans don’t call for it, but wanted to slide a piece of heat shrink tubing over the wires. Almost forgot and had to remove a couple of pins from the connector to slide the heat shrink over the wires. The four wires from the GPS-2020 use the same color code as its predecessor the GPS-250. The orange wire goes to pin 2, gray/orange wire to pin 5, gray/purple wire to pin 8 and the black wire to pin 9.

Although not called for, heat shrink was placed over the wires for an added layer of protection.

Completed DB-9 connector for the SkyView GPS-2020 module ready to be inserted into the AV-50000A Interconnect module.


Fellow builders following the DOG Aviation Blog may have noticed it appears as though the panel wiring is taking a long time and the wires in the area of the AV-50000A interconnect module are a mess  … all true. Part of the reason is I have been dragging my feet a little is because I have been waiting for a couple of things. The Adel clamp just aft of the cooling fan is woefully anemic for the amount of wires that need to go through it. The clamp was sized before options like ADS-B and the AP & Knobs Panel Modules were available and somewhere in the plans, even Van’s suggests the clamp can be switched to a larger size if necessary. Because of those additional options being installed, plus the fatter shielded cables used for the light/strobe circuits, the clamp is just too full for my liking ... so a larger clamp was ordered which hopefully will show up today. The other issue is one of the three panel pieces being powder coated was messed up on one side and the powder coater was not sure which side would show and figured he had a 50/50 chance … unfortunately, the side that was messed up shows. That happens to be the center section and really need that piece now to work out the possible interference issue with the backup airspeed indicator and the ABS-B module that was identified a few weeks ago.


The goal is to quickly finish up the instrument panel wiring and plumbing the additional backup instruments, then place the upper forward fuselage skin back in place so work can begin on fitting the cowlings.

Wiring Discrepancy Identified In Trim Circuit When AP Panel Module Installed

Time to break out the popcorn this another long post ... believe I have tracked down a wiring discrepancy in the plans when incorporating the Dynon Autopilot Panel module during new construction. There appears to be a discrepancy involving the trim motor wires in the Fuselage connector at pins 31 & 32.


When the AP Panel is installed, the trim motor’s power wire and the wires from the panel mounted trim switch are moved to the AP panel  module because it now becomes the controller for the pitch trim motor. Step 2 on page 31B-4 of the plans instructs the builder to place a battery on the two white trim motor wires  from the WH-P30 trim cable to determine which of the two white wires in the cable moves the trim tab UP when a positive voltage is applied to the wire. Once identified, that wire is called the “Trim UP” wire because it moved the trim tab up when a positive voltage is applied to it … (do not confuse this with nose up trim). Next the plans instruct the builder to insert the now identified “Trim Up” motor wire in pin 31 of the Fuselage connector and the remaining white  trim motor wire goes to pin 32. Of course, following the plans the “Trim Up” wire was placed in pin 31 of the Fuselage connector as instructed. I can’t say with certainty this is a mistake for all RV-12’s but it appears to me it is a mistake for RV-12’s under construction and installing the optional Autopilot Panel module. Below is the rational for that conclusion.


Return from the future 4/9/2016: Vindication!!! The trim motor worked precisely as I predicted it would based on the  circuit analysis below. The Van's plans are indeed in error ... when installing the Autopilot & Knobs Panel modules during the building process, the wire identified as +Trim Up definitely needs to be placed on pin 32 of the fuselage connector to make the trim move correctly when pressing the panel mounted trim switch.


As a side note for builders: When the trim tab on the stabilator moves UP it produces nose down trim. So don’t confuse the “Trim Up” movement of the trim tab with actual nose up trim. The physical movement of the trim tab is opposite to that of the desired trim. Another words, pressing the panel mounted switch calling for nose down trim should result in an upward movement of the trim tab. Likewise, pressing the panel mounted trim switch calling for nose up trim should create a downward movement of the trim tab.


As mentioned above, when installing the Dynon AP Panel, the wiring for the trim motor gets changed in such a fashion that the AP Panel module becomes the controller for the trim motor and the trim up/down switch on the instrument panel is wired directly to the AP Panel module. Because of this, I wanted to verify how the panel mounted switch is wired so I can wire in the corresponding wires coming from the hat switch on the Tosten CS-8 grips to the co-pilot trim inputs on the AP Panel module.


This brought me to studying the latest Van’s schematic showing the Dynon AP Panel's wiring diagram and comparing that to how the Dynon SkyView instillation manual says the AP panel works with the trim motor. This got me suspecting the polarity appears to be wrong at the Fuselage connector ... seemingly there is an error in the instructions on page 32B-4 in that the "Tab Up" wire should go to pin 32 and not 31. Of course, the Dynon manual's description may be incorrect, but doubt it since the manual has been out for a few years and revised at least once ... and the wiring call outs remained the same.


Felt it was time to do “ a little FBI 007 type investigatin' ” to coin a phrase from a Dr. John song. As an exercise to understand and verify the wiring, I used an Ohm meter to check the entire circuit beginning at the panel mounted trim switch. First it was verified that pressing the panel trim switch forward calling for nose down trim placed a ground on pin 18 of the connector on the back of the AV-50001 Switch & Fuse Module … it does. Next the brown wire (F-2035) attached to pin 18 of the connector on the WH-00031 wiring harness that plugs into the back of the AV-50001 module was tested. Per the schematic, the brown wire (F-2035) applies the ground coming from the down trim switch to pin 4 of the connector on the back of the AP Panel module labeled “Pilot Trim Down” in the Dynon manual. OK ... so far so good.

Testing to verify pin 18 on the switch connector wiring harness that plugs into the AV-50001 Switch and Fuse module is connected to pin 4 of the connector that plugs into the back of the AP Panel … it is. Looking closely, one can see a yellow/blue wire was placed on pin 18 of the connector and connected to the Ohm meter … at the connector for the AP Panel a wiring pin was placed on pin 4 so the meter reading could be taken.


Here is where the wheels fall off: For nose down trim, the trim tab needs to move UP meaning a positive voltage needs to be applied to the previously identified "Tab Up" wire that was placed in pin position 31 on the Fuselage connector earlier when completing the instructions in section 32B-4 step 2.


Reading the description given in Section 18 of the Dynon SkyView Instillation manual when a ground is placed on pin 4 (Pilot Trim Down) the AP module applies voltage to the trim motor by placing a negative voltage on pin 7 and a positive voltage on pin 8 of the connector on the back of the AP Panel module.   Following the wire from pin 8 of the AP Panel module back through the AV-50000A connections module it goes to pin 32 in the Fuselage connector … WHICH IS INCORRECT because as previously determined on page 32B-4, the wire placed at pin 31 needs the positive voltage to move the trim tab UP.

The Autopilot wiring  harness was plugged into the AV-500000A control module and as can be seen where my finger is pointing, the Ohm meter was connected to pin 4 on the connector for the AP Panel module to verify there is was continuity to pin 32 of the Fuselage connector … there is.


Assuming the Dynon Instillation manual is correct, and the AP module will place a positive voltage on pin 8 when down trim is called for, that positive voltage is going to pin 32. I submit to the reader that when the AP panel is installed, the instructions given in step 2 on page 32B-4 are incorrect. The correct wiring when the AP module is installed in a non-flying RV-12 should place the previously identified "Tab Up" wire into pin position 32 of the Fuselage connector ... and the remaining white wire goes to pin 31.


Today I flopped the two wires so now the “Tab Up” wire is on pin 32 and the remaining white motor wire is on pin 31. Now when nose down trim is called for, the positive voltage on pin32  will run the trim tab up.

The white wire with the red sharpie marking my finger is point to is the “Tab Up” wire that was moved from pin 31 to pin 32.


If moving the trim motor wires turns out to be wrong (strongly doubt it if the AP Panel works as Dynon says it does), I will be sure to return from the future in a week or so and edit this post accordingly. But at this point in time, if the Dynon SkyView Instillation manual is indeed correct, by switching the trim motor wires at the Fuselage connector the movement of the trim tab should be correct when power is applied to the avionics and testing begins. The goal: Trim tab moves up when nose down trim is called for … Trim tab moves down when nose up trim is called for.


While the 15 pin connector for the AP Panel module was open, two wires were added. The nose up trim wire from the hat switches on the Tosten control grips was placed on pin 5 (co-pilot pitch trim in-UP) and the nose down trim wire from the hat switches was placed on pin 6 (co-pilot pitch trim in- DOWN). The wires were covered with heat shrink, installed and the connector was closed up.

Installing an additional two wires in the connector for AP Panel. The wires are from the hat switches in the Tosten grips. Nose up trim was attached to pin 5 (co-pilot pitch trim in - Up) and nose down trim was attached to pin 6 (co-pilot pitch trim in - Down).


Regular readers of the DOG Aviation Blog may recall when wiring the switches on the Tosten control grips, with the exception of the push to talk switches, all the stick grip switches were wired in parallel. I chose this method for wiring the hat trim switches on the grips because the RV-12’s panel mounted trim switch is wired directly to the Pilot pitch trim inputs on the AP Panel module. Logic inside the  Dynon AP Panel module’s built in trim controller gives the pilot's input overriding precedence over the co-pilot inputs. During critical phases of operation the pilot should have a hand on the throttle ... as such the panel mounted trim switch is within finger reach and capable of overriding the trim inputs from either stick since they are both wired to the co-pilot inputs on the AP Panel module. I felt this was a good safety feature should a passenger or myself accidently get snagged on the hat switch during critical phases of flight. The trim controller in the AP Panel module also has a built in adjustable two step speed controller ... so the trim motor speed can be slowed down when flying faster so as to not be so sensitive ... yet the motor can speed up when flying at slower speeds. The built in trim controller also has run away trim prevention logic … in that, it will only run the trim motor for five seconds at a time. Should a trim wire get shorted or a switch stuck, the logic will only run the motor for five seconds, as opposed to letting the motor run until the trim tab is moves to its full limit. All nice stuff in addition to all the extra features the AP and Knobs panels will add … which makes adding the Dynon AP Panel a much welcomed addition to the DOG Aviation RV-12’s avionics.

Adding Functions To The Garmin GTR 200 Radio

One of the nice features about the Tosten CS-8 control stick grips installed on the DOG Aviation RV-12 is that in addition to just one button to key the radio’s transmitter, there is also an abundance of switches available to control other functions.


The Garmin GTR 200 radio’s wiring connector has two unused ground activated discrete inputs available … DISC1 (pin2) and DISC2 (pin22). These discrete inputs can be programmed to perform various functions within the Garmin GTR 200 radio using a built in menu option for the discrete set up page which lists various functions the discrete inputs are capable of controlling. Two of the functions seem quite appealing, so will be dedicating two of the switches on the Tosten CS-8 grips to control the Garmin GTR 200 radio’s two discrete inputs for the following:


Frequency swap (this will toggle the stand-by and active frequencies).
User frequency cycle (ability to cycle through a list of up to 20 user stored com frequencies).


Either of the discrete inputs can be programed to control the above functions, so it is the builder’s choice. That said, the current plan is to wire one of the Tosten grip’s switches to create a frequency swap button wired to the DISC1 input on pin 2 and use a second switch to control the DISC2 input on pin 22 for cycling through the database of user stored com frequencies.


At first sight, the massive connector on the back of the GTR 200 looks intimidating … but it is not. Two Philips screws secure the connector onto the radio’s mounting frame and once removed, the connector is in your hand. There is a flat metal plate secured with two screws covering the wiring … when removed, it reveals the wires entering backside of the connector.

Wiring harness/connector for the Garmin GTR 200 radio after removal from the radio’s mounting tray. The two cover screws have been removed along with the cover and the connector is now ready for inserting the two wires from the switches on the Tosten grips. One wire will be inserted into pin 2 to control discrete input DISC1 and a second wire will go to pin 22 to control discrete input DISC2.


It was a little bit of a fight trying to insert the two wires from the switches on the Tosten grips under the heat shrink covering the wires entering the Garmin GTR 200’s connector. There are quite a few heat shrink splices for the grounding of all the shielded cables that seemingly get in the way no matter there the wires are inserted. It took quite a bit of time before both wires were inserted under heat shrink, but it can be done. This is one of those tasks where the builder needs to try a few times at various locations, roll the heat shrink around in your fingers a little to rearrange the wires a little and try again … so patience is a virtue.

Making measurements on where to cut the wires to add the female connector pins.

The connector pins were installed on the ends of the wires, the brown wire was inserted into the DISC1 input (pin 2) and the blue wire was inserted into the DISC2 input (pin 22). Now that the two discrete inputs on the back of the Garmin GTR 200 radio’s connector are wired to switches on the Tosten CS-8 control grips, a couple of more steps will be required to make it all work. This will need to wait until it is time to power up the avionics. For those interested, section 3.6.4.5 of the Garmin GTR 200 Instillation Manual shows how to use the radio’s internal setup menus to enable the discreet inputs and assign their functions.  Next, referring to the Garmin GTR 200 Pilot’s Guide manual page 5 begins the tutorial on how to save com frequencies to the user com frequency database … this database can store up to 20 com frequencies that can now be cycled through using one of the stitches on the Tosten grips. At this point in time, the menu setup to make this all work will have to wait until the radio is installed and the RV-12’s electrical system is ready to be powered up.

A Day Of Working With The Wiring Connectors

There are quite a few connectors that need to be taken apart to either have wires added or removed … some wires are added as part the normal process of installing the wiring, others for additional options such as the AP & Knobs panels, and a few necessary for DOG Aviation modifications. Did not take a photo of every change, but mostly took photos of the connectors that required extra attention. The following is a synopsis of the work session.


The WH-00046 Fuselage connector: This connector needed to have the wires from the trim motor cable installed. A few months back the two white trim motor wires were tested with a battery and marked to denote which of the two white wires moved the trim tab UP when a positive voltage was applied to the wire … that wire was subsequently marked “Tab Up”. The “Tab UP” wire is placed in the Fuselage connector at pin 31. The remaining white wire in the trim motor’s cable is placed into pin 32. That leaves three wires in the trim motor cable that are color coded … the white/green wire goes to pin 4, the white/blue wire goes to pin 22 and the white/orange wire goes to pin 25.

The white trim motor wire held between my thumb and index finger was  previously determined to be the “Tab UP” wire and connects to pin 31of the Fuselage connector … the remaining white trim motor wire goes to pin 32. This is one place where it behooves the builder to check and recheck again to make sure you get this right.


Return from the future: The above information was based on the manual page 31B-04 rev 0. It appears to me there is an error on that page regarding the placement of the “Tab UP” wire into pin 31 on the Fuselage connector … can’t speak for a regular instillation without the AP Panel (but guessing it is wrong for that too), but when installing the AP Panel module on a non-flying RV-12, I believe the “Tab Up” wire needs to be placed in position 32 on the Fuselage connector. Read about my analysis in this post:


http://www.dogaviation.com/2016/03/wiring-discrepancy-identified-in-trim.html


If all this turns out to be incorrect, I will return from the future and edit this post accordingly … but I truly don’t think that will be necessary.

Before closing up the Fuselage connector, two wiring modification need to be made. Because the DOG Aviation RV-12 is adding a panel mounted switch for the electric fuel pump, the fuel pump’s power wire needs to be intercepted … this involves removing the fuel pump’s power wire from pin 29 on the Fuselage connector and replacing it with a short piece of wire that will connect to the panel mounted fuel pump switch … the removed wire will connect to the load side of the fuel pump switch and will supply power to the fuel pump whenever the fuel pump switch is on. The second modification is the addition of the wire from the canopy latch micro switch which was added to the DOG Aviation RV-12. The wire from the canopy micro switch needs to be installed onto pin 8 of the Fuselage connector.


The WH-00046 Options connector: There is one wire here that needs intercepting due to a modification. The Otto switches being used on the DOG Aviation RV-12 for the fuel pump and left landing light are from the same family of switches Van’s uses in the Switch module and also have internal LED lights. Because the level of brightness is controlled from the Dynon SkyView (or a potentiometer depending on the version of the electrical system) feel LED lights in the two switches to also be dimmable as well. Seemingly the easiest way to accomplish this is to intercept the cockpit “light-“ lead on pin 18 of the Options connector. A new wire will run from pin 18 to pick up the cathode of both switch’s LEDs then continue on to the roll bar’s cockpit light as usual.

Crimping a pin on a wire that will be inserted into pin 18 on the Options connector to intercept the Light- lead so the brightness of the LED’s in the two panel switches for the fuel pump and landing light can be controlled.


The WH-00031 wire harness connector: Builders not installing the AP & Knobs panels will not need to fuss with this connector. Because the DOG Aviation RV-12 will have the optional AP & Knobs panels, it will be necessary to perform a little surgery on the connector. The connector (one with the white label) that plugs into the back of the AV-50001 Switch & Fuse module receives the most attention if adding the AP & Knobs Panels. This is because the AP Panel becomes the controller for the RV-12’s trim motor and this necessitates removal of the wires in the WH-00031 harness associated with trim motor’s power and up/down wires from the panel mounted switch in the AV-5001 module. These wires are to be pulled out of the connector, pins covered with heat shrink and then tied back.

My finger is pointing to the connector on the WH-00031 harness that plugs into the back of the AV-50001 module. The three wires needing removal from this connector are pins 15,18,19.


When removing the wires from the connector, I used the spare wire with a connector on the end of it trick to push the old wires out from under the heat shrink. This allows the new wires to follow the same path under the heat shrink. Worked like a champ.

Holding the three wires that were removed. These now need to be covered in heat shrink and tied back. Looking closely, one can see the spare wires with female connectors that were used to push the old wires out from under the white heat shrink. These will be used to aid in inserting the replacement wires under the tight heat shrink.


The pins on the removed wires were individually covered with heat shrink and the wires were folded back and placed in another piece of heat shrink tubing.

The three wires individually covered with heat shrink, folded back and about to be inserted into another piece of heat shrink. These three wires will be replaced with wires from the AP wiring harness.


The three replacement wires from the AP & Knobs panel wire harness were installed next. Decided to do this while the harnesses was still on the bench. This may create a little hassle while routing the wires, but should be a lot less bending over the instrument panel in the long run … hopefully. The two harness were mated on the bench and the three wires from the AP & Knobs panel harness were connect directly to the WH-00031 wire harness connector. In addition, a piece of heat shrink tubing was placed over the three wires where they will be lying on the Garmin radio’s frame. The red wire is trim motor power and connects to pin 15, the brown wire is “pitch trim switch –“ and connects to pin 18, the remaining white/yellow wire is “pitch trim switch +“  and connects to pin 19.

Above the wire tie, one can see the three wires from the AP & Knobs wiring harness that replace the previously removed wires. The red wire is trim motor power and connects to pin 15, the brown wire is “pitch trim switch –“ and connects to pin 18, the remaining white/yellow wire is “pitch trim switch +“  and connects to pin 19.


Yet another modification … after receiving verification from Van’s that the unfused “Extra” circuit can indeed support up to 5 amps, an additional wire was added to pin 14 on the WH-00031 connector to bring this circuit out for supplying power for the left landing light.

One can see the added modification of the red “Extra” power wire on the far right connected to pin 14 on the connector. This will bring the “Extra” power circuit out to power the left landing light’s steady on through a panel mounted switch. Note: This circuit will need to be fused because the “Extra” circuit has no internal fusing inside the AV-50001 module.


The WH-00020 wire harness EMS connector on the EMS-220: I opened up this connector unnecessarily thinking I would need to add a wire to complete the circuit for the canopy latch micro switch. During construction of the DOG Aviation RV-12 Van’s came out with a canopy latch warning system by adding a canopy latch micro switch. Per the instillation instructions for the retrofit, in order to make the SkyView see the micro switch, it requires running a wire to the EMS-220. After opening the connector, up I realized my wiring harness was new enough that this wire was already in place …. should have looked to see if the pins were in the connector first. For older RV-12’s installing the canopy latch micro switch, in addition to the wire from the micro switch to pin 8 of the fuselage connector, a wire also needs to be run from pin 12 on the EMS connector (WH-00020 harness) to pin 27 on the EFIS connector at the AV-50000A Control module.