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Electronic Automatic Temperature Control ( EATC ) Retrofit

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The Ford Mondeo hit our roads in 1993, and has consistently been a sales success. Now on its 4th incarnation, it remains a drivers favourite.
For more information, visit the Ford Mondeo forum on, the definitive resource site covering all Fords from the present day to the 1970's.

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Overview Guide
Ford Model: Mondeo
Petrol/Diesel: ????
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Required Parts

Here is the full list of parts you could require; the route you choose to go for will then determine which of these items you need.

  • EATC Control Unit.
  • Interior Temperature Sensor.
  • EATC Fan Motor.
  • Sunload Sensor.
  • New Dashtop Airvent Grille to accept the new Sunload sensor (your old grille can be suitably modified if your handy with a drill)
  • Wiring (preferably removed from a complete Ghia/Ghia X dashboard loom but if not then a selection of ends with some wiring will do but will require lots of joins to be made instead of just one like a complete loom will require)

If you're going the plugs only route you will need:

  • EATC control unit plug with wires (either plug as the pins inside are the same: you need 6 wires/connectors from inside it)
  • EATC fan motor plug with wires (remove the connector @ pin 1 ready to accept the lead from pin 1 of your current motor's connector (leaves the other 3 wires in the plug nice & tidy & means a much easier job)
  • Interior Temperature Sensor connector plug to connect the temperature sensor to the EATC control unit
  • Sunload Sensor Plug to also connect this up to the EATC control unit
  • Lowest Green Fusebox Plug for one of its connections (to power the interior temperature sensor)

If you're going the full wiring loom route you will require:

  • Ghia/Ghia X dash loom from which you will need the following:
    • Fan motor wiring (earth lead & 2 wires to the control unit - the 4th wire can simply be removed from the plug very easily)
    • Temperature & sunload sensor wiring (this is the one that may take the longest to remove as one wire goes all the way to the fusebox & it's also joined to a 3rd sensor already in place on your car (this 3rd sensor will need to be cut off (one wire) from the other sensors but make sure you leave enough wire to easily connect the wire from the car at the minute to it later)

(It's also worth marking the wires' locations as you remove them for easier refitting later. Make sure you're cutting off the correct sensor wire too as the sunload & the sensor wiring you're cutting off have the same kind of plug & the wiring colours are almost identical too, but the wiring is reversed at the plug. This can easily be reversed if you do make a boo-boo though.)

Parts.jpg Vent.jpg


There are 3 levels of upgrade:

Option 1

Getting The Look but not the full function.

The manual knobs can be directly replaced for the digital unit no wiring changes required, this gives you a quick "sexy looking dash" - the digital unit will work for temp control, air direction, aircon on/off and recirc. However, the fan speed has to be set using the manual knob and this knob left behind the dash after reassembly.

Option 2

Installing an auto fan too.

This has four connections running to it. Green / Red (or) Brown power this already exists in manual aircon cars it can be used to power the auto fan. Black (earth) -just earth this to a suitable point under the dash. Brown/Blue connection which goes to the No 1 connection on Black socket on the back of the Digital Control unit. Blue / White connection which goes to No3 connection of the same socket.

(On Manual Aircon cars, Connection No1 will have a black / white running to it just cut this off and connect the brown / blue wire).

You can leave the manual fan speed switch behind the dash as it is redundant now.

Both the white and black harness sockets for the control unit can be easily taken apart by sliding the end cap off an then removing the plug with cables, you need a bionic eye here but the holes have been numbered in each corner.

When this modifcation is completed you should have a fully working (manual) digital control unit - all functions except the Auto.

Option 3

The Full Retrofit.

There are 2 additional sensors, the sunload sensor which fits into the screen demister vent. This vent will need to be removed as you need to drill a hole (same diameter as the sun load sensor - about 12mm) in the circular blank.

drill the hole where the circular mark is on the underside of the vent as seen in the following piccies

Where To Cut The Hole.JPG The Hole Cut.JPG

dont worry if you make the hole a little too big, simply wrap insulating tape round the sunload sensor to pad out the sensor so it fits into the hole snugly & your suitably bodged then ( just dont make too big a hole though as there is only so much the top of the sensor can hide)

The most awkward part I found was running the sunload sensor cables (2 of them) through to the control unit. In the end I removed the speedo housing and drilled a 5mm hole into the demister vent under the dash and fed the cables through - BE CAREFUL HERE NOT TO DRILL INTO AND THROUGH THE TOP TRIM OF YOUR DASH.

Alternative Sunload Sensor Wire Threading Method

after removing the dashboard vent grill, feel round & you will feel a join sealed by a foam/sponge type padding, insert a suitable screwdriver through this section as a aid to keep the gap open while you thread the wire

How To Thread The Sunload Sensor Wires.JPG

now remove the speedo cluster ( Follow The bits of this guide you have not already done ) & then you can use the gap created to feel round for the end of the screwdriver, once found you can thread the sunload sensor wiring plug through beside the screwdriver & into the vent space, then just thread it through the central loop ready for when you insiert the sensor after fitting the grill & remove the screwdriver

Fully Dismantled & route Fro threading the sensor wire.JPG Sensor Wiring Inplace.JPG

The interior motorised sensor will clip into a recess under the drivers trim to the left of the steering wheel - you will see a slotted vent about the size of a 10 pence piece.

Vent Hole.JPG Interior Temperature Sensor Inplace.JPG

Once this has been done you can re-assemble everything as I was able to work with just the radio removed.

The motorised sensor has four cables one of which is power that is fed to the fuse box.

the wiring connections for the full retro-fit are as follows :-

The Blower Motor

Climate Motor Pin 1 - Feed From Normal Heater Motor Pin 1 ( Green/red stripe ) ( can be simply removed from the old plug & widened by 2mm or so to fit into the new motors plug )

Climate Motor Pin 2 - To a suitable ground ( needs to be a sturdy ground )

Climate motor Pin 4 - Control Unit Black Plug Pin 3

Climate Motor Pin 5 - Control Unit Black Plug Pin 1 ( replacing the wire already inplace - this wire can either be cut out & the new wire attached to the bit left in the black plug or removed & taped up safely & then the new pin fitted in its place )

if you need to know what pin is what on wiring plug for the motor ( due to you not having a wiring plug to use ) then see the following picture for reference

Fan motor plug.jpg

the wiring should look something like This ( this piccy is minus the Pin 1 Power Feed As Thats Still On The Car )

Fan Motor Wiring.jpg

the modification required for the old connector is as follows, simply unfold the side flap of the connection to widen the plug enough as shown in the pictures below

Problem Plug.JPG Solution.JPG

The Sensors

Special Note

Control Panel Black Plug Pin 16 Provides a common power feed for all the sensors used to monito the climate & is already inplace on the car so will either need tapping into for the 2 new sensors or it will need removing & replacing with your own mini loom for the sensors & then the removed pin connecting upto the mini loom ( whichever way you find best really )

Sunload Sensor Pin 1 ( brown/green wire ) - Pin 16 Black plug on the control panel ( common power )

Sunload Sensor Pin 2 ( white/blue wire ) - Pin 18 White plug on the control panel

  • Note Regarding Interior Temp Sensor - the wiring colours on the sensor unit can differ to those listed below ( ford decided to change the sensor wiring colours during production & have kindly also left off any pin number ID on the connections too , they operate the same though )

Interior Temp Sensor Pin 1 ( White/green wire - alternate = Green/White ) - Pin 16 White plug on the control panel

Interior Temp Sensor Pin 2 ( brown/green wire - alternate = Green/Brown ) - Pin 16 Black plug on the control panel ( common power )

Interior Temp Sensor Pin 3 ( green/black wire - alternate = Purple/Black ) - Pin 10 of C501 of the fusebox ( see following piccy to see where that is - look for the single wire on the green plug )

Interior Temp Sensor Pin 4 ( Black/Green wire - alternate = Black ) - Pin 2 White plug on the control panel

The Wiring Should Look Similar To This - The Colours In This Wiring Loom Is Not Correct Due To Using Alternative Wires For The Loom But They Are Marked Up For Each Location On The Tape on Each Wire.

Sensor Wiring.jpg

power for the interior temperature sensor motor

to fit the wire into the plug you will need to remove the plug from the fusebox, prise out the red plastic clip to its 1st stop, then insert the pin your putting in into the correct location & then push the red clip back into the plug & refit the plug to the fusebox

Fusebox Power.jpg

wiring to the 2 control panel plugs - this is what your plugs should look like when finished

white plug wiring - look for the folded back wires

White Plug.JPG

black plug wiring - look for the folded over wires

Black Plug.JPG

To fit These wires simply do the following - after removing the tie wrapped that secures the wiring to the plastic surround of the plug ( not pictured but you will see it when your working  :) )

Step 1.JPG Step 2.JPG Step 3.JPG Step 4.JPG Step 5.JPG

now only do one plug at once to avoid confusion as they can look very similar once the covers are off ( OK the amount of wires is a givaway really but its easier to work on one plug at once )

The numbers for the holes are on the side of the connectors & you will have to count up/down from the nearest numbered hole to find the one you need

Pin Numbers.JPG

The Control Panel

with the above done the wiring is complete, you just need to tuck the old manual motor speed wiring plug out of the way & re-assemble the car & you should be sorted.

Things To be Aware of & checks to make

Mine is still all working well - the temp inside the car is being maintained and as a quick check once all the wiring is complete if you turn the temp up full the fan will slowly speed up and then once the desired temp is achieved will slow down. (there is a slight delay - say 10 seconds). Once you have the auto working and select it none of the indicator lights on the EATC control unit will light up (not even the Aircon one) as the unit is doing it all automatically) - your aircon will kick in and out automatically. Obviously all this can be manually overridden by selecting your own settings (the indicator lights will then illuminate your desired settings).

Another check is when you select screen the auto fan should come in on high (aircon on although the light will not come on)and all air directed to the screen.