EM50 Fiat Interface Unit
Overview
The EM50 was developed to interface between the habitation electrical system and the (then new) Fiat X250 Cab as introduced in 2007; 3 versions were created, A,B, & C.
The A version was used on all Auto-Trail Apache/Tracker, Cheyenne, & Frontier models, polyfuse rating and step time was set to match the slide out Omnistep Auto-Trail used split charge was not incorporated as this feature was built into the EC225 & EC325/8 power systems fitted. Originally fitted with a 15A fridge fuse, this was changed to a 20A type with the introduction of larger fridge 12V elements in 2009. In 2011 the step polyfuse was changed to match the C version, allowing larger steps to be fitted if required.
The B version was specific to Lunar motorhomes up to 2009, and was as per the A version but had a split charge relay fitted to match the EC200 system fitted.
The C version was used by Auto-Sleepers and was as per the A version but had a larger step polyfuse and step time was increased to match the Project 200 step fitted.
It should be noted that whilst the EM50 was designed to interface directly with Fiat base cabs, it was also used in Auto-Sleepers Mercedes models.
Fuse Allocation & Jumper Configuration
Fuse Allocation
F1 = 2A EM50 Supply
F2 = 7.5A Marker Lights
F3 = 20A Heater **
F4 = 20A Air Conditioner **
F5 = 20A Electric Step
F6 = 5A Awning / Entry Light
F7 = 20A Fridge
F8 = 20A Split Charge Supply **
F9 = 20A Vehicle Battery
** Depends on vehicle specification
Configuration (Jumper) Settings
Pins joined = ON pins open =OFF
1 = Step operates with LOCK
2 = Step operates with UNLOCK
3 = Awning / Entry light operates with Step
Connections
Signal Input (Red)
Pin SES Description
1= THIRD BRAKE LIGHT FEED FROM CAB
2= D- SIGNAL FROM CAB (-VE ENGINE RUN)
3= VEHICLE SPEED SIGNAL
4= DOOR LOCK SIGNAL
5= DOOR UNLOCK SIGNAL
6= REAR DOOR SIGNAL INPUT TO CAB
7= CEILING LIGHT +VE SUPPLY FROM CAB
8= CEILING LIGHT -VE SUPPLY FROM CAB
9= CAN BUS SIGNAL (LOW)
10= CAN BUS SIGNAL (HIGH)
11= SIDE MARKER SIGNAL FROM CAB
12= AIRCON SIGNAL FROM CAB
13= IGNITION SIGNAL FROM CAB
14= HEATER SIGNAL FROM CAB
15= NOT CONNECTED
Connections in red show signals not used by the EM50.
Connections in amber show optional signals that could be used by the EM50, if the vehicle manufacturer required.
Connections in black show required signals
Outputs (white)
1= THIRD BRAKE LIGHT FEED
2= AWNING LIGHT FEED
3= FEED TO AUX AIRCON
4= DOOR LOCK SIGNAL TO REAR DOOR
5= DOOR UNLOCK SIGNAL TO REAR DOOR
6= REAR DOOR SIGNAL (DOOR CONTACT)
7= CEILING LIGHT +VE
8= CEILING LIGHT -VE
9= STEP SIGNAL +VE STEP IN (OMNI ORANGE)
10= STEP SIGNAL +VE STEP OUT (OMNI PURPLE)
11= SIDE MARKER FEED
12= STEP LIMIT SWITCH SIGNAL (OMNI GREY)
13= STEP OPERATE SWITCH (PUSH BUTTON)
14= FEED TO AUX HEATER
15= ENTRY LIGHT FEED
Connections in amber show outputs that are only available if option used by vehicle manufacturer.
Connections in red show signals not used by the EM50 but passed through for future use.
Connections in black show standard outputs available for use on any version of EM50.
Power Outputs
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