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Close up of the MFU.

The two columns of white bi-pins are for the lights. There is a push button for Tx set-up and two trimmer dials.

The top trimmer dial(VR1) is for adjusting the dead band or channel 3. Channel 3 in standard mode triggers the long horn(up) and short horn(down). The trim on this channel is used to change to the hazard(up) and lights(down) mode. The trimmer dial is used if the horn sounds when the trim is moved to either max position. The trimmer dial is turned counter clockwise all the way and then slowly turned clockwise until the horn sound stop. The dead band is then set.

The second trimmer dial(VR2) is for the vibration unit. Turning it either way decreases or increases vibration.

The mini switch controls two different turn signal modes.

The servo leads from the MFU goto the Rx and the servos plug in directly above the leads.

Top left six pin is for the trailer light harness.

Other conections are speaker, control unit, vibration unit and coupler switch.

secretsg

MFU is even easier with Digital Trims. Here's Willy's explanation on it [link]http://mitglied.lycos.de/wloewer/Tanks/id79.htm[/link]
He could explain it ten time than I ever could. The page uses Tamiya Tank DMD/MFU units as an example but the semi's are
similar.

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I see what you are saying, but with the rigs modes are turned on, used and then shut off. If you used this process and decided to honk the horn while you were driving with the trailer, the trailer would detach or lower the legs while in motion. That would be bad. That is why certain modes have to be shut off completely so that they are not accidentally activated.

I have never used a digital Rx system. If the trims could be switched by the push of a button, that would be much eaiser.

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The Knight Hauler is the only big rig that has a fully concealed control unit that has easy access and is protected. Tamiya designed this disguise to add even more scale feature to the Knight Hauler.

Here is a list of control unit locations on other rigs:

King Hauler: Passenger side tool box, fully exposed
Globe Liner: Under body in back, facing forward
Ford Aeromax: In fuel barrel facing down, fully exposed
Merc-Benz 1838LS: In fuel barrel facing up, fully exposed
Merc-Benz 1850L: In fuel barrel facing out, fully exposed
Volvo Globetrotter: In uel barrel facing up, fully exposed

At the control unit you can turn on the rig(full functions).

The second switch controls static display with lights only or full drivability without sound, vibration or lights.

The first button controls the hazard lights at the panel.

The second button controls the use of the speed indicators on the roof lights. One light for first gear, two lights for second gear and three for third.

The third button controls the light functions at the panel.

Then you have the volume.

All these functions are controlled by the Tx as well aside from the speed indicators and volume.

Lunchboxer

So for Aeromax, it is explosed to the bottom? Hmm.. does not seem like a smart idea.. (rock / dirt / water / etc.) No?

I was set to get the Aeromax.. maybe I need to re-think about that.. ?! What do you think?

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Let's put in the transmission and drive shaft!

First we have a view of the underside of the rig. Almost real, except for that battery cradle.

I little tipping a turning and the tranny slips in snug.

Once the tranny is in it can slide forward to accept the main shaft.

Lunchboxer

The old Bruiser actually let you fill up the tranny with oil (you need to seal the tranny from outside using silicon).. that was pretty interesting.. wonder why Tamiya did away with that.. I guess you can always do that by sealing up the tranny yourself...

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Take a look LB...

Lunchboxer

Hmm.. maybe I should get the Knight Hauler Metallic edition.....

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...and a pair of sunglasses...LOL

J/K man, that would be cool.....

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Quick shot of the speaker box and vibration unit.

Nothing special here and fairly straight forward. This box comes with the Knight Hauler kit. All the other rigs use the speaker box that comes with the MFU unit. It is half this size.

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So now that all the boring stuff is out of the way, lets attach the speaker box and MFU.

First we need to attach the mounting plate. This comes as part of the KH kit and is used mainly for the interior seats if you don't have the MFU. We do have the MFU, so the seats will stay on the tree.

The speaker box is mounted with four "L" brackets, you can see two of the four in the pic.

Note the three wiring harnesses from the control unit. There is a bit of forward thinking required here. All the wires must be tucked in neatly or pass through tight spots. Figuring this out before major components are installed will keep you from redoing things two or three times.

*I will note these wiring tips when possible.

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I should also talk a bit about the integration of the accessories when building the tractor. The instructions are typical of Tamiya, although some areas lack adequate explination.

The integration of all the parts for the Motorized Legs can be confusing at times. One piece is replaced for another identical piece only to have a slight modification. Tamiya tries hard to make this easy, but I felt that they slacked in some areas.

For example: When parts are integrated, there is no information as to which screws, washers and small parts are re-used from the tractor kit and what is used from the accessory's kit. Some items that are not used are shaded, but still can be a bit confusing. The Motorized legs come with a lot of extra parts and it is easy to mistake one part for another.

Secondly, the manual for the Motorized Legs does not have a parts list for each step like most manuals do.

The next few steps will cover this area.

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Before we can mount the speaker box and other gear, we need to run some wiring first.

The front mounted servos for steering and transmission both need cable extensions. They will need to be run under the speakerbox unit.

Connect the motor bullet connectors to the MFU. These wires will also need to be run under the speakerbox.

Once all the wiring is complete, there is not much room to spare and the more wires tucked away makes for an easier time attaching the body.

The next set of wires to be run from the front under the speakerbox is the fog lamps. I ran the wires between the servos and then along the servo cables to the back access.

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LIGHTING

OK, so now that those wires are done, here's some pics of how the lighting works. Tamiya includes some aluminum reflectors to give a more realistic look to the main lights. They keep all the light focused forward and prevent any light lost from the backside. There is also one on the rear brake lamp.

The foglamp, front lamps, rear lamps and reverse light are all assembled in this fashion.

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Since the front lamps are assembled, lets take care of the lighting for the body.

The headlamps are installed as shown. The roof lamps are very straight forward(sorry no pics for that[])

Tip: I used some 600 grit sandpaper behind the grill so that none of the wires can be seen. It makes for a more scale look as well.

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If you have the Trailer light accessory, this is the time to install that as well. Pretty straight forward.

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So, you're probably thinking, how the heck am I going to know what wire is what when they all come together in a big mess of wires?

Tamiya took care of that too. Each wire gets a label, even the servo leads. Each label gives plug location, wire color and bulb location. I recommend putting the labels one inch from the PLUG end.

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It's not time to install the speaker box just yet, we still have to run the wires for the tail lamps, reverse light, coupler switch and coupler servo.

First we will run the wires for the rear lamps and reverse lamp. I zip tied all the wires into one strand and attached them to the drivers side of the chassis. You can not run the wires on the passenger side if you are using the motorized leg function as it will interfere with the servo horn.

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Tamiya supplies three great clips for mounting the wires onto the frame rails.

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The next step is to assemble the coupler. We need to assemble this now because there is a switch integrated into the coupler. When the trailer is attached, the switch activates a coupling sound and also switches the ESC into a different power mode for pulling the trailer. We need to run the switch wire before we install the servo.

The instructions are straight forward on this assembly. I will explain how it works in the next post.

CustomTamiyas4Life

My Feedback: (34)

That looks like a tough build.

Lunchboxer

Man, the semi looks like a really cool project.. definitely not your typical buggy that takes a night or two to build.. !! Very cool.. I think I will like that!

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Tough, but extremely satisfying.

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Eric, more like 20-25 hours of build time for the tractor alone. The trailer was another 10 hours.(including paint and finishing)