The WH-RV12-IGNITION Wiring Harness Installed

Continued working on the firewall forward wiring but got a little sidetracked doing some research of the wiring schematics and VAF forums regarding a couple of wiring enhancements planned to be incorporated in the coming days. As a result, only completed installing just a few wires … the WH-RV12-IGNITION wiring harness being among them.

The WH-RV12-IGNITION wiring harness ready to be connected to the ignition modules.

The WH-RV12-IGNITION wiring harness is made up of two shielded wires that require some attention to be installed correctly. The plans keep referring to the wires using color references of white/blue for the J-152 and blue for J-153 … however, as can be seen in the above photo, both wires in the harness are white. Fortunately, a yellow heat shrink identification band is placed on both ends of each wire. The J-152 and J-153 wires plug into the only vacant positions on the A1 and B1 plugs with J-153 going to the A1 connector and J-1532 going to the B1 connector.

Looking closely, the vacant connector position can be seen where the connectors are labeled A1 and B1.

Inserting the J-153 wire into the only vacant position on the A1 connector.

There is a portion of insulation that has been removed from both the J-152 & J-153 cables exposing the braided shielding underneath. The bare shielding needs to be carefully positioned under the metal clamp that supports the wiring harness for the A1 and B1 connectors … there should be no insulation under this metal clamp because it provides a ground for the shielding. When the shield for both cables is in position under the clamp, the M5 hex screw securing the clamp is to receive Loctite and be tightened to 22 inch pounds. Also, because this assembly was taken apart during engine preparations for mounting, care must be taken to insure the ground wire is also reattached under the head of the mounting M5 screw as can be seen in the second photo below.

The M5 hex screw securing the grounding clamp and ground wire is torqued to 22 inch pounds.

My finger is pointing to the ground wire and clamp that provides the grounding for the shielding on the J-152 and J-153 cables … only bare shielding should be under the clamp.


Both shielded wires in the WH-RV12-IGNITION wiring harness are to be run down along the main wiring harness for the ignition modules as can also be seen in the above photo.


At the other end of the WH-RV12-IGNITION wiring harness is a Molex connector housing which will interface to J-762 and J763. Here again, the wires are referred to in the plans by color but both wires are white … fortunately, they too have heat shrink identification bands. The both wires need to be inserted into the Molex connector so when the connector halves are mated together, J-762 mates with J-152 and J-763 mates with J-153.

The Molex connector at the end of the WH-RV12-IGNITION wiring harness connected to J-762 and J-763 (wires on the right) … the connector housing still needs to be secured with wire ties.


Still need to tie wrap the Molex connector, but one additional wire will need to pass by this location so will wait until it is in position before securing the connector housing.

Wiring Of Starter & Master Solenoids, Battery, Starter - Completed

When continuing with the firewall forward wiring this work session, hit a bump in the road almost immediately. Van’s plans call for crimping an ES324082 crimp ring terminal with a 1/4" hole onto the P-157 wire which is a 12 AWG wire that feeds battery power to the AV-50001 Switch and Fuse module. Looking closely at the ES324082 ring crimp terminal revealed it is actually a terminal for #8 wire and won’t fit into my ratcheting crimping tool so it would require using the hand crimping tool. Because the P-157 wire is the main battery power buss to the AV-50001 Switch and Fuse module, felt it was wrong to knowingly crimp a connector designed for #8 wire onto a #12 wire ... so headed out and picked up a replacement ring terminal with a 1/4" hole designed for #12 wire.

One can see the hole in the yellow #12 ring terminal will fit the white #12 AWG wire much better and should make for a much tighter crimp on the wire  as opposed to hand crimping the red ES324082 #8 ring terminal onto the wire.


Once the P-157 wire had a ring terminal attached, it was placed onto the terminal on the starter solenoid closest to the left side of the airplane along with a #8 wire coming down from the master solenoid. The remaining terminal on the starter solenoid closest to the right side of the aircraft is for P-155 a #8  wire that supplies power to the starter motor. The P-157 wire is plenty long enough that should it be necessary to change to the other connector for some obscure reason, it can easily be done.


The custom ground cables Stein Air made for the DOG Aviation RV-12 came in a couple of days ago, so decided while working in the vicinity, now would be a good time to install them.

The Van’s original P-149 battery and P-151starter cables with the red terminals will be replaced by longer custom cables that Stein Air fabricated with white heat shrink covering the crimps. The longer cables will reach the grounding block modification on the firewall.


The longer custom P-149 battery ground and P-151 starter ground cables were installed onto the ground stud on the firewall (a grounding modification made to the DOG Aviation RV-12). The P-155 starter power cable was attached to the stud on the starter solenoid on the right side of the aircraft and connected to the starter. The nuts on the 992-819 starter relay and starter power wire at the starter were torqued to the specs given in the Rotax Illustrated Parts Manual of 35 inch pounds.

Completed wiring of ES-24115 master relay and 992-819 starter relay which is below the starter relay and mostly hidden by the white rubber boots covering the terminals. Also of note, the protection diode covered in blue heat shrink is normally installed on the other mounting bolt for the starter relay … because the engine is installed, this bolt was far easier to use as the ground point for the diode.

The new longer ground cables (P-149 battery and P151 starter) are now connected onto the firewall ground point … a modification installed on the DOG Aviation RV-12. For safety, the ground lead is not connected at the battery and the negative terminal has been taped over. Still need to use a couple of wire ties to secure the cables.


Have to admit, all this took far longer than it should have … had most of the wiring been done prior to mounting the engine, as suggested in the plans. But when wiring of the solenoids had just begun, the owner of the borrowed engine hoist needed it back so the wiring was placed on the back burner and the engine was mounted. Everything is still accessible … just more challenging.

Preparing The EGT Sensor Wiring

Yesterday’s work session was a somewhat abbreviated session as far as forward progress is concerned. Mike was working on his snowmobile so thought it was only fitting to return his kerosene heater back to his hangar so he could have some heat. Knowing it was going to get cold quickly in the hangar, did not start on anything major … but did get a chance to run all the firewall forward wires through the Adel clamp hung on the WD-1221 engine mount standoff. The wires coming from the grommet in the firewall were a jumbled mess, so they were untangled and fed through the Adel clamp one at a time until my fingers got cold enough I had to stop and head over to Mike’s hangar to warm up.


After finishing tidying up the wiring going through the Adel clamp, went back to the plans and was surprised to see the next step involved cutting off all four female spade connectors on the two Dynon supplied EGT sensors and replace them with female spade connectors. I had to scratch my head about that a bit … but upon inspecting the connectors on the sensors, quickly realized the body of the Dynon connector is just a bit larger than the connectors Van’s supplies with the RV-12 kit so then will not play nice together … plus they are a slightly different style in that the body has straight edges and not the rounded middle section like the Van’s spade connectors have. Also, it appears that the Dynon connectors have a much larger gap where the male spade connector would slip into the female connector compared to the Van’s supplied connector.

The two white connectors are the female spade connectors on the ends of the wires of the Dynon EGT sensor. The red connector is the Van’s connector … notice it has a rounded middle section and the gap where the male spade connector would slide into is much less which, in theory, should also lend itself to a tighter fit.


A note to fellow builders: The individual wires inside the Dynon EGT cable have some sort of heat protection woven around each wire. Care must be taken when stripping the wires to make sure all the fibers are removed from the wire so they don’t interfere with creating a good solid crimp on the wire.

The Dynon EGT sensor with the red connectors has been converted over to the Van’s supplied female spade connector. The sensor on the left still has the Dynon female spade connectors … but not for long.


Once converting the Dynon EGT sensor’s wires to the Van’s female spade connectors, the plans instruct the builder to place male spade connectors on the two wires inside each brown cable that makes up the WH-RV12-EGT exhaust gas temp wiring harness.

Installed More Wiring Harnesses & Modification Of Pitot Tubing

Moving thorough the plans, the WH-00062 power wiring harness was the next wiring harness that needed to be installed. This harness brings in the power to the AV-50001 switch module. Van’s has made a change to the plans regarding the routing of wire WH-P156 … older versions of the plans route the WH-P156 wire(s) through the firewall grommet and into the engine compartment to the Ducati voltage regulator, however newer versions of the plans show the WH-P156 wire(s) routed down under the instrument panel base to the new home for the Ducati regulator. Not wanting a high current device such as the Ducati regulator with a history of smoky failures inside the cockpit, the decision has been made to keep the regulator somewhere in the engine compartment. So all the wires in the WH-00062 wiring harness were routed through the firewall grommet and into the engine compartment.


The next wiring harness tackled was the WH-RV12-EGT harness. This harness consists of only two wires that are routed into the engine compartment through the firewall grommet. The wires will connect to the exhaust gas probes on each side of the engine that measure exhaust gas temperature. The DB-25 connector on the WH-RV12-EGT wiring harness attaches onto the SkyView EMS-220 engine monitoring module. The DB-25 connector comes without a housing attached so it was necessary to open a bag containing the clam-shell housing for the DB-25 connector, screw down the strain relief and snap the clamshell halves together. Initially, I thought the connector may receive more wires which is why the housing was not attached … but a quick look at the wiring schematic showed only the two EGT probe wires going to the connector.

Installing the strain relief on the housing for the DB-25 EGT connector.

Fishing the WH-RV-12-EGT wiring harness through the firewall grommet.

The connector housing did not have a label as most all of the other connectors do, so used the label maker to make an EGT label to stick onto the connector's housing.

The WH-RV12-EGT harness’s DB-25 connector attached to the SkyView EMS-220 engine monitoring module.

The next step in the plans instructs the builder to route a 54 1/2" piece of what appears to be a form of vinyl or poly tubing through the firewall grommet and on into the engine compartment … this becomes the FF-1216 forward Pitot tube.  Here is where the DOG Aviation RV-12 will make a tiny modification and deviate from the plans … normally a 4" piece of vinyl tubing is used to splice the forward Pitot tubing coming from the engine compartment to the aft Pitot tube going to the ADAHRS mounted in the tail cone.

My finger is pointing to the piece of 4” vinyl that normally would be used to splice the forward Pitot line to the aft Pitot line … this will not be done because of the need to tap into the Pitot line for the backup airspeed indicator.


Because the DOG Aviation RV-12 will have a backup airspeed instrument, it is necessary to tap into the Pitot line. So in lieu of using a piece of vinyl tubing to splice the forward and aft Pitot lines together, a "Y " designed for tubing will be used to split the Pitot line coming from the engine compartment so one leg can head aft to the ADAHRS module in the tail cone and the other leg of the "Y" can connect to the Pitot port on the UMA backup airspeed indicator.

The "Y" fitting will allow the Pitot tubing from the engine compartment to be split so the backup airspeed instrument can also receive Pitot air.


At this point in time, will wait to install the Pitot line going to the UMA Backup airspeed indicator until the instrument is installed in the panel and the best routing for the tubing can be determined.


For those builders interested, the Y fitting was obtained from Stein Air. They have many types to choose from such as manifolds, T, elbow and straight fittings. Most of the fittings are also available with or without pipe threads so they can be connected directly to instruments.

Instillation Of The ACK E-04 ELT Completed - Finally

It felt good finally wrapping up the instillation of the ACK E-04 ELT without any more time consuming difficulties. While about to mount the ACK E-04 ELT using the metal straps, noticed the inside edges of both the front and aft latches were quite sharp … so prior to mounting the ELT, the sharp inside edges were removed with a few strokes of sandpaper.  With the ELT set in place on its mounting bracket, the latches were snapped closed securing the ELT in place.

Mounting the ACK E-04 ELT on the mounting bracket using the provided metal strap and spring loaded latch.

With the ACK E-04 ELT securely mounted, the antenna mounting bracket and antenna was temporarily mounted so the antenna's coax cable could be adjusted to length and the excess coax slack taken up with wire ties. (The antenna bracket will be removed so the fuel tank will be easier to install). The audio panel was mounted next and an attempt was made to neatly manage the excess wiring slack using wire ties.

Completed instillation of the ACK E-04 ELT ready for testing.

After the ACK E-04 ELT and accompanying hardware was installed, decided to test the unit again. This time I had my handheld radio along and tuned it to 121.5 MHz and at the top of the hour armed the ELT and pressed the reset button on the remote control panel indicator. The radio picked up the audio bursts and the LED on the remote control panel indicator flashed so all appears to be functioning. Will have to wait until the instruments are fully installed and the RV-12 is outside so the GPS antenna can lock onto the satellites to be able verify the ELT is receiving GPS data using the optional data out wire on pin 2 of the mini din connector.

The ACK E-04 ELT Instillation – The Saga Continues

My hope for this work session had been to finish off the instillation of the ACK E-04 ELT … but that was not to be because of the exorbitant amount of time spent on wiring four pins on the ELT’s miniature din connector, but more on that rant later.


Van’s places the ACK E-04 ELT on the right side of the RV-12 above the center channel and behind the right seat. The mounting tray that that comes with the ACK E-04 ELT needs to be riveted onto the inside of the fuselage after drilling a couple of mounting holes. The aft portion of the mounting tray is secured with Clecos using two existing rivet holes in the F-12122 bracket so the two forward holes in the mounting tray can be match drilled into the F-1204H bulkhead cap.

With the aft end of the ACK E-04 ELT mounting tray secured to the F-12122 bracket with Clecos, the forward two holes in the bracket are match drilled into the F-1204H bulkhead cap using a #30 drill bit.


After drilling the forward mounting holes into the F-1204H bulkhead cap, the mounting tray was removed and the two holes were deburred. At this point, two metal straps are placed under the mounting tray before it is riveted … the strap stamped BATTERY is placed under the aft end of the mounting tray and the strap stamped FRONT is placed under the forward end of the mounting tray. The rivets used to secure the tray/straps to the fuselage are the larger head SB-42-BSLF baffle rivet.

Riveting the ACK E-04 ELT’s mounting tray onto the fuselage using SB-42-BSLF baffle rivets.

With the ACK E-04 ELT’s mounting tray and straps riveted in position, the next step in Van’s plans instructs the builder to refer to the ACK E-04 manual for guidance on wiring the ACK supplied mini din plug (nightmare) connector that will furnish power and a GPS signal to the ACK E-04 ELT along with an optional test wire to verify the ELT is receiving the GPS signal. Here is where the wheels fell off the production wagon. For starters the ACK instillation manual says the mini din connector has solder cups and that the wires are to be soldered… the connector they supplied in the box DOES NOT have solder cups, it has gold pins. Included in the Van’s hardware for installing the ACK E-04 ELT are 4 gold plated female pins of the crimp variety and of the type designed to be enclosed  in a connector housing. The spacing of the pins makes the connectors practically touch one another and if the wires flex they will touch. Once the connectors are slipped over the tiny (and very short) pins on the mini din connector, they almost touching one another … especially at the base of the pins and they are very wobbly and easily moved by the wires. Frankly, this is the worst interfacing I have ever seen … the setup is totally daft. I was half tempted to chop off the mini din plug and use a "real" four wire plug and socket designed to fit together … but figured I could improve on the hot mess and move on so as not to have to wait for parts from Mouser. If this connector gives an inkling of trouble, it will be chopped off and replaced with a quality connector.


For starters, instead of soldering the wires to the female connector pins, the tiny pins were crimped using my crimping tool with special dies for tiny connector pins. All the crimps turned out better than expected considering how tiny the pins are.

Placing a wire in the jaws of the crimping tool.

Zooming in on this photo of the GPS signal wire and the ground shield, one can see the pins supplied are a split female type without any insulation or a connector body to fit into like they are designed for … frankly, in my opinion, all wrong for this application and beyond daft!!


In an effort to mitigate possible shorting of the connectors and to make the connections tighter, after the wires were crimped onto the pins, a piece of TINY heat shrink tubing was placed over the female pin and was left a few thousands longer than the female pin … then a heat gun was used to shrink the tubing before sliding the female pin onto the tiny male pin on the mini din. This made the female connector fit much tighter onto the tiny male pins coming out of the mini din connector because the heat shrink compressed the female fitting tighter to the pin.

Zooming in on this photo, one can see one female pin has the heat shrink covering it and the other does not. The viewer can see just how close these pins come to touching one another along with also seeing how tiny and short the pins exiting the mini din are.


The ACK wiring instructions say to connect the white/red power wire to pin 1, test data out to pin 2 (this is a short piece of wire that is not necessary but can be used as a troubleshooting aid to verify a GPS signal is being received), the shield ground from the GPS cable to pin 3, and the GPS signal wire to pin 4. The pin callouts in the ACK instructions are viewed from behind the connector on the side where the wires attach.

All the wires are now connected onto the mini din connector.

The ACK instructions say to fill the connector body with RTV … so the high temperature RTV that was available in the hangar was squeezed into the connector body and the two halves placed together. Before sliding the housing up over the two halves, more RTV is placed on the wires where they exit the two halves of the connector then the body is slid up and over the two halves locking them in place.

The mini din connector sitting in half of the housing. RTV will be used to cover the wires and fill the housing before the other half of the housing is mated.

Finished connector with a little red RTV oozing out the slots on the back of the cover.

Not wanting to disturb the wires until the RTV has had a chance to cure a little, will wait until the next work session to mount the ELT unit and audio panel onto the mounting bracket then dress the wires and keep my fingers crossed the mini din connector is functional.