Replacing the Heater Control Pack Originally written by TB of MEG

This is a common fault on Mk1 mondeos and some Mk2's although corrected for later Mk2's.

The heater resistor pack (also referred to as the resistor control pack) control's the speed of the cabin fan. At positions 1 and 4 the pack is bypassed, however when the select switch is in position 2 or 3 the excess power is directed through a resistor which enables the fan to spin at a slower speed. If your fan isn't working when on positions 2 and 3 (although sometimes 1 and 4 are also effected) or if you have recently noticed a strange burning smell / smoke coming from the passenger side footwell then chances are your control pack is on the way out.

You need:      

• Revised Wiring Assembly
  • FINIS - F1056972 125107 - £4.80
• Revised Resistor Pack Assembly
  • FINIS - F1066902 126407 - £6.06
• Insulating Tape
• Wire Cutters
• Thorx Screwdrivers
• Soldering / Crimping Equipment

You may need:

• No other equipment required

The first thing to do is remove the glovebox and sound deadening foam to gain access. To remove the glovebox open it and then tug sharply toward the rear of the vehicle. The sound deadening may or may not be in place and you may or may not have to remove it to get complete access.

With the box removed you can see the heater resistor pack (Labeled A above). The pack is screwed to the bulkhead with a single thorx screw. Unscrew and withdraw the pack.

This image shows the state of the existing pack and wiring connector. You can clearly see where the wiring connector has burnt and melted the plastic. Use the wire cutters to chop the old resistor pack AND connector off. You should be aiming to cut about 4 CM back from the old plug although if there is heat damage to the cable at this point cut as far back as required.

Next you need to solder or crimp on the new wiring connector assembly. Match each colour up and solder or crimp it to the existing cable. Two points here, 1) Use an old rag when soldering to stop any unwanted splashes of solder melting your carpet and 2) These cables carry a significant amount of current. They must me soldered or crimped into position ("chocolate" screw down boxes will also do). Never just twist them together!!!

Finally insulate each connection separately using as much tape as required to ensure they never come into contact with each other. Connect your new resistor pack to your new connector and reattach it to the bulkhead.