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Discussion Starter #1
I've made another thread here on the MK1 forum, but it's not getting any responses so here I am! So far I have the following parts collected from the junk yard:
  • Cruise control servo/module w/ cut-off wiring harness
  • Steering wheel with buttons
The next step is to simply make a wiring harness and route it through the firewall. There's 10 wires in total that need to be connected, so hopefully this doesn't take too much longer BUT I am having issues.

Problems:
  • I cannot figure out where pin 3 is supposed to be going in the wiring diagram (PDF linked here). It says it's supposed to go to pin 1 of the PCM. Does anyone know of an easy way to track down this wire from the PCM?
  • Where on earth can I get a little wiring harness through the firewall? There is THIS area above and to the left of the clutch pedal where all the wiring goes through, but I think this hole is surrounded by solid plastic. Not only that, but this side of the engine compartment is very crammed.

Observations:
  • The '05-'07 Foci seem to be somewhat pre-wired for cruise control. For example, the wiring connector for the brake position sensor is unused but included in my Focus:


  • Also, here is an image from my clockspring connector (click to see a large version):



    As seen in the wiring diagram, the brown and white pins for this connector are used for the cruise control buttons. MY CAR HAS THESE WIRES, along with most of the other wires needed, but I have no idea where they end. Because of this, I guess I'll need to make my own wiring harness, and tap into all of these wires throughout the car.

If anyone has any input, or has managed to retrofit cruise control, please let me know! I am very surprised at how little this issue has been covered on the internet.
 

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I cannot figure out where pin 3 is supposed to be going in the wiring diagram (PDF linked here). It says it's supposed to go to pin 1 of the PCM. Does anyone know of an easy way to track down this wire from the PCM?
Hello. When doing this kind of modification, you need the complete Ford Wire Diagram for your 2007. The complete wire diagrams are never/rarely shared here so you need to purchase them. I bought my 2004 paperback book on ebay for about 15 bucks. The official paperback book or PDF wire diagram has great info beyond the basic stuff. I highly recommend you buy the same/similar stuff. The 2007 wire diagram has ALL of your answers and more.
 

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Discussion Starter #3
Thanks for the response Marde! I'm a bit confused on this, because I believe I do have access to all the wiring diagrams. Perhaps I am not looking in the right area though for the PCM though - would you be able to look it up in your wire diagram to see if it's in there?

The diagrams I'm using are from the Auto Repair Reference Center which I have access from through my school, and so far it seems to have a ton of stuff.

EDIT: I can see a "Body Computer" and "Computer Data Lines" section, but I don't think that's the one I'm looking for...
 

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C2H5OH
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Look at the middle PCM connector pin #1, it will be empty. This means you'll have to add that pin/wire.
The PCM connectors are 175A, B and C.

In factory form, there is a junction running into the side of the car behind the fuse panel. It exits in the wheelwell and from there runs to the Speed Control Module mounted to the firewall.

Pull the kick panel, see the black junction?
Look around for another very similar to it. That will be where cruise runs through.
 

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Thanks for the response Marde! I'm a bit confused on this, because I believe I do have access to all the wiring diagrams. Perhaps I am not looking in the right area though for the PCM though - would you be able to look it up in your wire diagram to see if it's in there?

The diagrams I'm using are from the Auto Repair Reference Center which I have access from through my school, and so far it seems to have a ton of stuff.

EDIT: I can see a "Body Computer" and "Computer Data Lines" section, but I don't think that's the one I'm looking for...
That might be BCM (Body Control Module) an equivalent to my PCM (powertrain control module). Maybe it is properly called BCM in your 2007.

In my wire diagram book, the cruise control is Vehicle Speed Control page 31-1 thru 31-4. Most MK1 foci have a single PCM connector C175. It seems only PZEV cars (in 2004) had 3 connectors on the PCM; C175B C175E and C175T.

I had an old pic of C175 in my photobucket (pic below). BTW, in earlier/different models the PCM connector was also called C414, C415 or C416. I do not have a pic of the C175B type connector. The B, E and T type connectors are square shaped 50-pin connectors. Based on what iminhell said, I guess 2005-2007 cars have 3 connectors at the PCM.



I have a PDF wire diagram for 2003 foci. There is a wire & block diagram of the Vehicle Speed Control. I am posting a pic of the Vehicle Speed Control block diagram bc it gives a good summary of the key components involved.



Look at the middle PCM connector pin #1, it will be empty. This means you'll have to add that pin/wire.
The PCM connectors are 175A, B and C.

In factory form, there is a junction running into the side of the car behind the fuse panel. It exits in the wheelwell and from there runs to the Speed Control Module mounted to the firewall.

Pull the kick panel, see the black junction?
Look around for another very similar to it. That will be where cruise runs through.
I know only basics about 2005-2007 type foci. Can you please confirm and help me learn... Are 2007 cars equipped with 3 PCM connectors? If yes, are they numbered C175A, B and C -or- like mine-> C175B, E and T? This question is for you, the OP, or anyone who knows.

My book shows the VSS signal connected at these points;
PCM C175B (pin-1) ->to-> Speed Control Servo C122 (pin-3)

The Speed Control Servo is also a Speed Control Control Module.

Thanks and Cheers!
 

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C2H5OH
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All the Duratec cars will have a 3 connector PCM.

random Google image:





And I think it might be B (Body), E (Engine) and T (Transmission). I'd have to look and I don't feel like doing that right now (have to fire up the other computer).
 

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Discussion Starter #7 (Edited)
Look at the middle PCM connector pin #1, it will be empty. This means you'll have to add that pin/wire.
The PCM connectors are 175A, B and C.
Thank you very much again for the reply. So after looking into this a bit more, I do believe I can use an alternative wire for this that would be MUCH easier to access: Pin 14 (Green/White) of the OEM Radio, which I do not use since I have an aftermarket head unit. This wire receives vehicle speed input. Here is a link to the diagram:

https://www.dropbox.com/s/b8da7nqt3rzs9do/sound-system-2007-ford-focus.pdf

Do you think this would work? Using the wire that's just sitting there would much easier, assuming it works.

In factory form, there is a junction running into the side of the car behind the fuse panel. It exits in the wheelwell and from there runs to the Speed Control Module mounted to the firewall.

Pull the kick panel, see the black junction?
Look around for another very similar to it. That will be where cruise runs through.
Underneath the kick panel, this is what I'm seeing (click the image for a larger view):



The orientation is a bit funny in this, but the top bunch of wires are going out toward the front of the car, and bottom bunch are going into the side. Are one of these wire bunches the one you're referring to that cruise control uses?

That might be BCM (Body Control Module) an equivalent to my PCM (powertrain control module). Maybe it is properly called BCM in your 2007.
Here's the two pages of the "Body Computer" diagram:

https://www.dropbox.com/s/ij2kjbwcxwslz00/body-computer-1-2007-ford-focus.pdf
https://www.dropbox.com/s/2inwtoxn0shq4hi/body-computer-2-2007-ford-focus.pdf

Nothing on those two pages seems to mention anything about speed, so I guess I don't have access to that information. Also, see my question above about using the vehicle speed wire normally going to the OEM radio above. This is what another guy used in a video when he installed cruise control in his Focus, so I'm assuming it would work.

Now one last thing (hopefully): I'm lost on what to do with pin 7. This goes to the battery junction box. In that YouTube video in the last paragraph, he uses an Add-A-Circuit for this (4:15 into the video). I'm confused though on where exactly this would be plugged in.
 

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C2H5OH
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I really don't see how this is so damn difficult for you, or anyone. It's basically 4 wires, power, ground, turn on and turn off.
If you don't understand the wiring diagrams, you shouldn't be attempting to instal it.
 

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Discussion Starter #9
I really don't see how this is so damn difficult for you, or anyone. It's basically 4 wires, power, ground, turn on and turn off.
If you don't understand the wiring diagrams, you shouldn't be attempting to instal it.
I'm sorry if I've irritated you. A project like this is a much more daunting task for someone like me. I only have experience installing simple things like head units that don't require drilling through a firewall or tracking down wires that are located all over the car. I'm trying my best to learn here and I won't stop until this job is done. Again, I appreciate the help you've provided so far.

Still confused on a couple things:
  • I posted a picture above with the two wire bundles. You said there was a second wire junction. Is the one pictured below the fusebox (bottom of the picture) where the cruise wires go through?
  • The '05 - '07 models seem mostly pre-wired, but I don't know if there's an easy way to find out where these pre-existing wires actually end. Does anyone know of a way to find this out, or should I just make my own wiring harness and tap into the necessary wires?
 

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...I do believe I can use an alternative wire for this that would be MUCH easier to access: Pin 14 (Green/White) of the OEM Radio, which I do not use since I have an aftermarket head unit. This wire receives vehicle speed input.

Do you think this would work? Using the wire that's just sitting there would much easier, assuming it works.
Yes, the VSS wire at the radio is the same as at the PCM, so if you can access that wire easier to tap into it then do so.
 

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I have compared the wiring diagram for your year against the one for my 04. I only see three differences.

1. The fuses that are used in yours are numbered differently, and also my kit came with an inline fuse that gets installed. None of that should make any difference. Just use fuse #29 as shown in your diagram to supply power to pin 7 of the servo.

2. Pin 3 of the servo goes to pin 28 of the PCM connector on my car. On yours, pin 3 of the servo should go to pin 1 of the PCM, or tap into the VSS wire at the radio. This is the vehicle speed sense output from the PCM. Note, there is no need to cut the wire, just strip some of the insulation off and splice into it.

3. Pin 1 of the servo goes to pin 4 of the instrument cluster connector on my car. On yours, pin 1 of the servo should go to pin 18 on the instrument cluster connector. This is the cruise control dash light.

Everything else seems to be the same.
 

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Discussion Starter #12 (Edited)
Thanks FocusKnot for those insights. Since most of the instructions I've been looking at deal with pre-'05 models, it's useful to see those differences.

Today I went into the driver's side wheel well, removed the lining and found this (Click the image links for larger versions):



The above is what's on the other side of this bunch of wires near on the left side of the footwell:



This connector is held together by a 10mm bolt, and when unscrewed and pulled apart this is what I see:



And here's the male side of the connector. Notice those gnarly pins:



Now having a closer look at the female side after pushing it through the firewall:



Cruise control wiring in '05-'07 Foci (without cruise of course) is wired up to this point - except pin 7. I have confirmed with a multimeter that the clock spring pins, the instrument cluster pin, and the brake/clutch sensor pins end here. I have yet to check the vehicle speed signal pin, but I'm sure it's there. These cruise control pins just don't get carried onto the male part of the connector.

From what I can see of the male connector, it appears to be tamper-proof, so you can't add any pins to it. You can't remove the bolt holding it together to add more to it. So now all that I'm left with is:

  • Confirm that my Focus is pre-wired for the power pins (pin 7 and clock spring pin 3) and the speed signal pin (pin 3).
  • Determine if I should take the male connector from a cruise-control Focus (with the cruise control harness intact), cut the main harness and solder it into my main harness. This would end up being more soldering work, since there's quite a few wires, but this way I would not have to drill through the firewall and I would have a proper factory cruise control harness. Does this seem like a bad idea?
 

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Seems like GOOD idea to lift all the factory harness you can to use that connector with a different plug in at the engine compartment side.

Double check where that all goes to see how much of the harness you can easily acquire & swap.
 

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Discussion Starter #14
Yeah, that would be excellent if the whole harness turned out to be a simple swap. That would keep things very simple. I'll have a closer look tomorrow. Currently I'm googling for a diagram of where that main harness leads to.
 

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C2H5OH
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It is not 'tamper proof'.
Remove the white part, there are 4 catch tabs that hold it in place. A pick tool and slight force and it comes loose rather easily.
Each pin has a single catch. Depress it and you can remove or add as you see fit.

The connector should be somewhere in this --> http://www.te.com/catalog/feat/en/c/33800?BML=10576,17560,17553,17684
You can buy parts through Mouser or Digi-Key. Both have catalogs that are pretty easy to navigate/sort. I use Digi-Key more because they are closer to me, 1 day shipping for me generally.
 
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Discussion Starter #16
I'll have another look at it then. Do you happen to know if this same connector is used on 2000-2004 Foci? If yes, I could just steal some pins from a local donor car I have access to and call it good. I could not find this specific connector on the te.com site you linked to unfortunately.

Also, this is a long shot, but if anyone has a Ford diagram of this connector I'd appreciate that. I'd like to keep track of the necessary pins and eventually post a how-to on this so others can do it without tracing the wires themselves. Failing that, I'll just post a picture with the cruise control pins highlighted.
 

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Here is the connector view you wanted. There are two of this type connector in the 2003 and 2004 cars. Referenced C70 and C71 in 2003 cars. Referenced C213 and C214 in 2004 cars. The connector in later cars (like ur 2007) might have been redesigned slightly because the retaining latches/clips on the side of the connector seem different than your pictures. I have never disconnected this one on my car, so I do not know what the retaining clips look like in person.



Edit: Wow, I have seen lots of multi-pin connectors in aviation and some have some goofy and confusing numbering verses pin-positions. This one is bad. Go ahead, count the pins in order, 1 thru 40. Terrible layout.
 

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Discussion Starter #18
Thanks for that Marde! That will come in handy. So now all BUT ONE cruise control pin is accounted for, and that's the pin 7 (Green/White - 12v power). This is supposed to go to fuse 29 (10A) in the fuse box next to the battery. Fuse 29 is missing in my car, and there's not any wiring for it. I guess that's not very surprising. Again, here's a link to the cruise control wiring diagram for reference:

https://www.dropbox.com/s/uehi89n4jba44fz/cruise-control-mt-2007-ford-focus.pdf

Any ideas on how to add that circuit? I'm not even sure where to tap into...

EDIT: Could I just route the green/white wire to the battery fusebox, crimp it into an Add-A-Circuit, and then just plug it in one of the available slots? Something like this:

 

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Have zero time to sniff around or chat... But the source of power for your mod is the (output of) the Power Hold Relay = power available only when key is in On or Run. There are many places and splices you can tap into this source of this power... and get your fuse "wired-up"".
 

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I am all about good/quality/professional work however.... If I was doing your CC mod, I would shortcut/bypass that firewall connector. I would find a good location in the firewall to drill or sneak the new wires thru -and- also do it with quality workmanship. In aviation experimental flight test, system mods shortcuts are sometimes used to test the system first. Once happy with the results of the mod, you can optionally re-do some/all of the work to be production grade quality if you desire.

There is nothing wrong with doing it right or by the book the first time. There is also little or nothing wrong with doing some shortcuts that make it easier + quicker + cheaper if using smart n safe workmanship.
 
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