Hi everyone,

I’m hoping to get input from members who have already completed the 4" → 5" MFD5 display retrofit on an EU Fiesta MK7.5, particularly ST180 owners, as I’m currently stuck diagnosing a very specific steering-wheel control issue that only appeared after the retrofit.

I’ve been working through this for several days now and I’m confident the issue is not wiring-, clockspring-, or SCCM-related, but rather a module compatibility or firmware interaction issue between the FCDIM and APIM.

TL;DR

If you have a working 5" MFD5 retrofit on a Fiesta MK7.5 (audio + voice steering-wheel buttons keep working after 20–30 minutes of driving), please share your FCDIM part number/strategy and APIM part number/calibration (NA or RB). I’m trying to confirm whether my issue is caused by the DC-strategy FCDIM, an outdated APIM calibration, or a configuration mismatch.

Vehicle & retrofit background

Car:

• Fiesta EU MK7.5 ST180

• Factory SYNC 1.1 (non-nav)

Hardware BEFORE retrofit

• 4" FCDIM: F1BT-18B955-SA

• Sony non-SATNAV stereo fascia: C1BT-18K811-SA

• Sony ACM: E1BT-18C815-HK (original ST180)

• Steering wheel module: AV1T-14K147-AA

• APIM (SYNC 1.1): D1BT-14D212-NA

• No reverse camera

Hardware AFTER retrofit

• 5" MFD5 FCDIM: F1BT-18B955-DC

• Same Sony fascia

• Same ACM

• Same steering wheel module

• Same APIM (SYNC 1.1)

• Added aftermarket reverse camera (working perfectly)

Configuration changes made

Only configuration options were changed in FORScan, no manual As-Built hex editing was done.

IPC:

• Touchscreen type → With Display, No Touchscreen, MFD5

• Park Assist Camera → Enabled

APIM:

• Display Feature Set → MFD5

Symptoms (started only after retrofit)

• Steering-wheel audio and voice buttons work normally after ignition

• After a few minutes of driving, all audio/voice SWC buttons stop responding

  • Volume

  • Track next/previous

  • Centre voice command button

  • Voice button on indicator stalk

• Cruise-control buttons continue to work at all times

• Audio, SYNC functions, and reverse camera continue working normally

• If the car is fully locked and sleeps for ~30 minutes, the audio SWC works again temporarily

Troubleshooting already performed

• Rebooted modules individually and in combination:

  • APIM

  • FCDIM

  • ACM

  • IPC

  • BCMii

• SYNC master reset

• Battery disconnected for 1 hour

• Verified wiring untouched during retrofit

• Verified clockspring and SCCM operation (cruise buttons always work)

Why I believe this is FCDIM/APIM-related

Based on the behaviour:

• SCCM and clockspring are clearly working (cruise never fails)

• CAN wiring is intact

• Steering-wheel button messages continue to be sent

• Only audio/voice SWC processing stops after runtime

This strongly suggests a logic/firmware issue where the FCDIM or APIM stops handling those events after a period of operation, rather than a hardware failure.

Current module details (problematic setup)

FCDIM – Front Control / Display Interface Module

• Part number: F1BT-18B955-DC

• Calibration level: F1BT-18B955-DC

• Strategy: F1BT-14D358-DC
   

APIM – SYNC 1.1

• Part number: D1BT-14D212-NA

• Strategy: E1BT-14D205-AH

• Calibration level: D1BT-14D212-NA (latest known: D1BT-14D212-RB)

What I’m looking for from members

I’d really appreciate replies from anyone who has completed this retrofit successfully and has no SWC issues long-term.

If your setup works correctly, could you please share following Forscan modules info:

FCDIM

• Part number (e.g. F1BT-18B955-DC)

• Calibration level (e.g. F1BT-18B955-DC)

• Strategy (e.g. F1BT-14D358-DC)

APIM (SYNC 1.1 only)

• Part number (e.g. D1BT-14D212-NA)

• Calibration level (e.g. D1BT-14D212-NA)

• Strategy (e.g. E1BT-14D205-AH)

And please confirm:

• Reverse camera enabled (factory or aftermarket)

• Audio + voice steering-wheel buttons still work after 20–30 minutes of driving

• APIM is still SYNC 1.1 (not SYNC 3)

Goal

I’m trying to determine whether this issue is caused by:

• A limitation or bug in the DC-strategy MFD5 FCDIM

• An APIM issue resolved by updating calibration from NA to RB

• Or a known incompatible combination of SYNC 1.1 + certain MFD5 variants
   

Any confirmed working data points will help not just me, but anyone else attempting this retrofit in the future.

Thanks in advance for reading, and apologies for the long post, I wanted to include enough details to avoid guesswork.

Edited December 27, 2025Dec 27 by iron_savior
typo

@JW1982

Tried to send you a DM but was getting a message that you cannot receive messages. Dont know maybe your inbox is full. I am pasting this draft here as a follow up to my initial post if you can help me.

Sorry for the long post, but I wanted to give you the complete picture upfront so you don’t have to chase missing details. I’m genuinely stuck on this one and really value your opinion and experience. I haven’t been able to find any detailed guidance online for this specific scenario.

Vehicle / baseline

• EU Fiesta MK7.5 ST180
• Factory SYNC 1.1 (non-nav)
• Steering wheel controls worked flawlessly for years before any changes
• No prior intermittent SWC issues, ever

Factory setup before retrofit

• 4" FCDIM: F1BT-18B955-SA
• Sony non-SATNAV fascia: C1BT-18K811-SA
• Sony ACM: E1BT-18C815-HK (original ST180 unit)
• Left Steering wheel module: AV1T-14K147-AA
• APIM (SYNC 1.1): D1BT-14D212-NA
• No reverse camera

Everything above worked perfectly long-term.

Retrofit performed

• Upgraded to 5" MFD5 display
• FCDIM installed: F1BT-18B955-DC (DC strategy)
• Same Sony fascia, same ACM, same SCCM, same clockspring, same wiring
• Same APIM (SYNC 1.1), unchanged hardware
• Added aftermarket reverse camera (works perfectly)

Important: No wiring modifications were made anywhere in the car during the retrofit.

Configuration changes
Only normal FORScan configuration options were changed — no manual hex editing.

IPC/BCMii backup:

• Touchscreen type → With Display, No Touchscreen, MFD5
• Park Assist Camera → Enabled

APIM:

• Display Feature Set → MFD5

No changes to:

• ACM
• RFA
• Any steering-wheel related As-Built

 

Symptoms (started ONLY after retrofit)

• Steering-wheel audio + voice buttons work perfectly immediately after ignition
• After a few minutes of driving:
  Volume up/down stops
  Track next/previous stops
  Centre voice command button stops
  Voice button on indicator stalk stops
  Cruise-control buttons continue to work 100% of the time
  Sony fascia buttons, audio playback, SYNC UI, and reverse camera continue working normally

 If the car is fully locked and allowed to sleep for ~30 minutes, or if I reboot the FCDIM module via FORScan, the audio SWC works again temporarily, then fails again after some runtime

This behavior is 100% repeatable.

What I have already ruled out

• Wiring (Didn’t touch car wiring looms)
•  Clockspring (Didn’t touch it and cruise always works, never drops)
• SCCM failure (Didn’t touch it and it continues to send cruise frames correctly)
• CAN integrity (no other modules affected)
• Power issues (battery disconnect, module resets done)
• Software lockups (APIM/FCDIM/ACM/IPC/BCM resets don’t change behavior)

I’ve also checked DTCs pre and post retrofit. There are some unrelated background or expected codes (camera/GPS/etc.), but nothing that correlates with the SWC dropout, and nothing pointing to SCCM or steering input failure.

Why I believe this is FCDIM/APIM logic related

• SCCM and clockspring must be fine (cruise never fails)
• Button inputs work initially, then stop only for audio/voice functions
• Failure occurs after runtime, not immediately
• Recovery only happens after full vehicle sleep or FCDIM module reboot from FORScan
• Only change that introduced the issue was the FCDIM upgrade

This strongly suggests the SCCM continues sending messages, but the consumer (FCDIM/APIM path for audio SWC) stops processing them after some condition is met.

Current module details (problematic combination)

FCDIM:
Part number: F1BT-18B955-DC
Calibration: F1BT-18B955-DC
Strategy: F1BT-14D358-DC

APIM:
Part number: D1BT-14D212-NA
Calibration currently NA (RB is the latest known)
Strategy: E1BT-14D205-AH

I’ve also confirmed that Motorcraft does not publish As-Built for FCDIM, so there is no official baseline to restore. FORScan shows internal config blocks, but I’m hesitant to copy values unless I know the donor is a confirmed working setup.

Thanks a lot for taking the time to read this. I’m out of ideas at this point and your experience could really help me avoid guesswork.

Kind regards,
Dimitris

To be honest I have never came across this exact problem or something similar.

The audio steering wheel controls are just a simple resistance circuitry where every button has its own resistance. The fact that it is working for a small period suggests that the circuitry is fine.

As far as I remember the steering wheel controls are directly connected to the FCDIM. I recommend to start checking the resistance values of every single button. When the resistors are out of tolerance the FCDIM will stop responding to the buttons. I have seen 1 or 2 times before that the resistance values changed by age/deterioration of the resistors.

If all resistance values are within specification the problem will most likely be the FCDIM itself. 

These 5 Inch FCDIM versions are updated from the SD-card containing the maps. Apart from the maps these SD-cards also contain the FCDIM firmware. I have seen before that downgrading to an older software version by inserting and old map SD-card and upgrading to the latest software version by inserting and the latest map SD-card fixed strange issues. This is worth a try.

Thanks mate for the detailed explanation, it helped a lot and I’ve since double-checked a few things based on your reply.

I can now confirm the following:

• SWC is indeed a pure resistive ladder (each button has its own resistance)
• SWC is directly connected to the FCDIM (not via CAN)
• Using FORScan “switch activity”, when the issue occurs all audio/voice SWC activity disappears completely (no button events at all)
• When the buttons are working, FORScan sees them correctly
• When they stop working, FORScan shows nothing until the car sleeps or the FCDIM is rebooted

This makes me agree with you that the resistive circuitry itself is very unlikely to be the cause, especially since it works perfectly at startup and then drops out together after runtime.

I also updated SYNC from 5.9 → 5.11 to rule that out, but the behavior didn’t change.

My current FCDIM SD card is V6. Based on what you mentioned, I understand these SD cards don’t just contain maps/TomTom software but also FCDIM firmware, and that a downgrade + re-upgrade has fixed odd issues before. I’ve also seen posts saying the last MFD SD card version is V12.

This is where I’m a bit stuck and could really use your experience:

• What is the correct/safe way to downgrade and re-update FCDIM firmware?
• Is this purely done by inserting older/newer MFD SD cards and letting the FCDIM flash itself?
• Is FORScan ever suitable for FCDIM firmware flashing, or is SD card the only supported method?
• If SD cards are the way, would it be reasonable to borrow older/newer MFD SD cards from donor cars and try a controlled downgrade → upgrade sequence?

I checked FORScan’s FCDIM firmware section but couldn’t find all required files, and I don’t want to risk bricking the unit by guessing.

At this point I’m leaning toward either an FCDIM firmware issue or a faulty DC-strategy unit, and I’m trying to eliminate firmware cleanly before sourcing another module.

Any guidance on the proper firmware update/downgrade process would be hugely appreciated.

Edited December 29, 2025Dec 29 by iron_savior
corrected info

Quote

I also updated SYNC from 5.9 → 5.11 to rule that out, but the behavior didn’t change.

This only updates the APIM software and does not affect the FCDIM in any way.


 

Quote

• What is the correct/safe way to downgrade and re-update FCDIM firmware?
• Is this purely done by inserting older/newer MFD SD cards and letting the FCDIM flash itself?
• Is FORScan ever suitable for FCDIM firmware flashing, or is SD card the only supported method?
• If SD cards are the way, would it be reasonable to borrow older/newer MFD SD cards from donor cars and try a controlled downgrade → upgrade sequence?

V6 is quite old on itself. This SD-card was released in 2016 and contains 2015 map material and the corresponding firmware. In this case I recommend to install the latest V12 SD-card.

The FCDIM firmware is embedded into the map file on the SD-card. Just put the SD-card into the slot and within approximately 30 seconds the system will either start upgrading or downgrading (depending on the current and previous SD-card).

In theory Forscan is perfectly capable to update the FCDIM firmware. However the required VBF files have never been publicly available from Ford. It is even not available on the Ford servers.

One more question if you don’t mind, just to make sure I approach this the right way.

If I can get access to a V12 MFD SD card from a friend’s Fiesta with the same setup, is it possible to use that card purely to update the FCDIM firmware, or are these SD cards VIN-locked / unit-locked in any way?

In other words:
• Can I insert a V12 card from another car, let the FCDIM update itself, and then remove the card again?
• After the firmware update is completed, will the FCDIM operate normally without the SD card present, just without navigation functionality?

I don’t plan to use navigation at all, the card would strictly be for the firmware update.

Also, just to set expectations correctly: if I perform the FCDIM firmware update via SD card and the SWC issue remains exactly the same, would you also conclude that the FCDIM itself is likely faulty?

Thanks again! I really appreciate you sharing your experience and helping me reason this through.

@JW1982
Hi mate. 

Following your last reply, I wanted to update you with some new findings and ask for your opinion.

I purchased a second 5" MFD5 FCDIM (F1BT-18B955-DD) and the SWC dropout issue persists exactly the same.
I’ve thoroughly checked all module configurations with FORScan; nothing unusual appears.
I then noticed some electrical tape intervention near the FCDIM plug and started considering wiring as the root cause. I have bought the car second handed and dont have a clue for any wiring modifications done. 
Another observation: the 5" FCDIM seems to perform stricter ADC plausibility checks than the 4" FCDIM. This explains why the 4" unit tolerated the same wiring.

Based on this, I’m now considering a more precise approach: measuring both resistance and voltage across the SWC wiring and at the FCDIM pins to confirm signal integrity.

Here is the test plan I’m planning to follow wiring diagram attached bellow:

1. Resistance measurement: Pin 10 ↔ Pin 7 at FCDIM, and Pin 4 ↔ Pin 2 at SWC for each button, both cold start and runtime up until SWC is broken.

2. Voltage measurement: DC voltage between FCDIM Pin 10 ↔ Pin 7, no buttons and each button pressed, monitored both cold start and runtime up until SWC is broken.

3. Check for: drift, instability, sudden jumps, or collapse of readings that could trigger ADC plausibility shutdown.

My goal is to confirm whether the dropout is caused by wiring/connector issues that only the MFD5’s stricter ADC checks detect.

I’d really appreciate your thoughts on this approach. Do you think these measurements will clearly identify the issue, or is there something else you would check first?

It is definitely a good idea to measure the resistance values. 

This can confirm whether the resistance values change or not and rule them out as the cause of the problem.


You can also try to change the configuration back to how it originally was (keep the MFD5 connected). Just to see whether this changes the problem or not.

@JW1982

Hi Wilco,

Quick update. I concentrated entirely on the steering wheel audio/voice controls as a pure analog resistive ladder feeding directly into the FCDIM analog input, as discussed earlier.

With the vehicle off, I measured resistance across SWC+ / SWC− in the loom going to the FCDIM connector (pins 10 and 7). Values were stable and repeatable:

Voice ~53 Ω
Volume Down ~138 Ω
Volume Up ~266 Ω
Seek Right ~453 Ω
Seek Left ~719 Ω
No buttons pressed ~1610 Ω

These all look consistent, with no intermittency during static testing.

With ignition on (engine not running), I measured voltages at the same pins with the 5" MFD5 FCDIM installed, holding each button for ~2–3 seconds to stabilize readings:

No buttons pressed ~2.38 V
Voice ~0.25 V
Volume Down ~0.58 V
Volume Up ~0.97 V
Seek Right ~1.37 V
Seek Left ~1.75 V

Voltages were clean and repeatable.

Reinstalling the original 4" screen and repeating the same procedure, I got (clean and repeatable):

No buttons pressed ~3.58 V
Voice ~0.43 V
Volume Down ~0.99 V
Volume Up ~1.60 V
Seek Right ~2.20 V
Seek Left ~2.74 V

So while resistance is identical, the voltage ranges are clearly different between 4" and 5" FCDIMs, suggesting different internal pull-ups or ADC scaling. Importantly, with the 4" FCDIM the SWC never fails.

The key behavior appears only with the 5" MFD5 and is clearly event-triggered. Pressing Seek Left causes the audio/voice SWC to stop working immediately. I confirmed this multiple times and also reproduced it on my second 5" MFD5 unit with exactly the same result.

The same failure can also be triggered by pressing the multifunction switch in certain corner positions, especially where Volume Up (and less often Volume Down) partially overlaps with Seek Right. This strongly suggests brief simultaneous or invalid resistance states inside the switch.

Once this happens, FORScan shows no SWC activity at all until the FCDIM is reset or the car goes to sleep.

To rule out time or heat effects, I drove for ~40 minutes with the 5" installed, deliberately avoiding Seek Left. SWC worked perfectly the entire time. The moment Seek Left was pressed once, the SWC failed instantly.

At this point, everything points to the SWC switch itself. Looks like the 5" MFD5 appears to apply stricter ADC plausibility checks than the 4" FCDIM and likely disables the input when it briefly sees an out-of-range or dual-contact condition.

Given the age of the car, the unknown history (I’ve owned it ~8 months), and some old tape intervention found in the loom, internal wear of the multifunction SWC switch now seems the most plausible cause.

I don’t have an oscilloscope and I’d rather avoid cutting the SWC wiring to add inline resistors, so my next step will be to replace the steering wheel audio/multifunction switch and report back with the result.

Quick question: can the SWC switch be removed from the trim without removing the airbag, or is airbag removal unavoidable?

Following up, 

Still straggling with this issue. I have booked an appointment next week with an automotive electrician to replace the SWC switch. @JW1982 or anybody it would be really helpful If anyone has already measured the SWC analog values on a known working Fiesta MK7.5 with 5" MFD5 FCDIM, I’d really appreciate it if you could share them here.

Measurements at the FCDIM SWC pins (SWC+ / SWC−) would be ideal:

• Voltage per button (ignition ON, engine off)

• Resistance per button (vehicle OFF), if available

Even approximate numbers would be very helpful for comparison.

To be honest I rarely worked on a Fiesta. 

The Fiesta MK7.5 schematics that I have do not list the resistor values. I looked at the Focus MK3 schematics that use the exact same FCDIM.


The Focus MK3 has the following resistance values:

Resistance without any buttons pressed  = 2450,3 Ω
Seek -  = 850,3 Ω
Seek +  = 502,3 Ω
Vol +  = 282,3 Ω
Vol -  = 142,3 Ω
Voice  = 53.6 Ω

 

@JW1982
Thank you very much for resistance values. Is it possible you send me Focus MK3 schematics with a PM?

FocusEU2014_cel130.pdf

Quick final update to close this thread. Issue fully resolved.

After replacing the steering wheel audio/SWC switch with a new one, the problem was still present. Pressing Seek Left would immediately cause the FCDIM to drop all audio/voice SWC input exactly as before. This confirmed the SWC switch itself was not the root cause.

The real breakthrough came when I unplugged the left indicator stalk.

Important detail:
The car had a non-OEM Fiesta ST180 left stalk and had the voice button which was the stalk for other Fiestas that dont have the voice button on the SWC switch, In the correct factory configuration, a Fiesta has voice either on the steering wheel or on the stalk, never both. 
As said i have purchased the car second handed and hadn't observed this very crucial non OEM involvement. Apparently, previous owner replaced the stalk with not the compatible for the Fiesta ST180.

With the stalk unplugged:

• All steering wheel audio/voice buttons worked perfectly

• No more FCDIM ADC shutdown

• No SWC dropouts

• No DTCs

• Issue completely gone

What was happening:
Both the SWC switch and the stalk voice button were feeding the same analog SWC ladder into the FCDIM. This created parallel resistive paths and invalid resistance states during certain button presses (especially Seek Left or edge/corner presses on the multifunction switch).
The 5" MFD5 FCDIM applies stricter ADC plausibility checks than the 4" unit, so when it detected out-of-range or dual-contact resistance values, it shut down the SWC analog input entirely, requiring sleep or reset to recover.

That also explains why:

• The fault was event-triggered, not time or heat related

• The 4" screen never showed the problem

• Two different 5" FCDIMs behaved identically

I’ve now confirmed:

• Steering wheel wiring is untouched and correct

• Clockspring is fine

• No CAN, coding, or firmware issue

• No fault with the FCDIM itself

Final fix:
I replaced the the incorrect stalk with the correct OEM ST180 stalk (no voice button) and the issue resolved.

Posting this in case it helps someone else. This was a tough one and very easy to chase in the wrong direction.

Big thanks to @JW1982 for the assistance.