Hi there, I new here & need help. I have gone through the complete diagnosis & testing on my 2004 F350 C&C XL model, 5.4 litre, speed control problem & had 3 tests confirm my problem as "repair circuit 10". I have tried to get wiring diagrams from Ford & numerous online sites to find out which wires are on circuit 10 so I can test for an open circuit but to no avail. I went to both Motorcraft service & Helm but because I am Canadian & not a registered shop or mechanical service they will not supply me with the info even when I tried to pay for it. Without a wiring diagram that actually show me the wires on circuit 10 of the speed control wiring system I cannot go any further. Can you guys help me.
PS: This site is awesome!
Mike

 

Ford service DVDs area available all the time on ebay. It pays to own your own copy.

I can't find a circuit "10" in the speed control diagrams for your truck.

 

I don't see a circuit 10. What did you do do diagnose? And did you get any codes from the speed control module?

 

dchamberlain
Thank you for your reply to my post. I used a Ford service manual for 2004 that gave me all the tests to perform on the speed control system & 3 of the tests confirm a problem in circuit 10. I went to the Ford guys & they could not find circuit 10 on their online wiring diagrams either so they were of no help. I did further tests & found a bad ground on the brake pedal pressure switch which I fixed. I then did the KOEO test again & it now goes further giving me 3 flashes indicating "Deactivator switch is open or circuit defective". I did a number of more tests & I am getting power to the speed control servo but nothing out of it so it is now leading me to a defective speed control servo. I need to find someone around here with a similar speed control servo that will allow me to borrow it & plug it into my vehicle to confirm that my problem is indeed the speed control servo. That's were I am at now.

projectSHO89 - Thank you for your reply also. I purchased from ebay one of those Ford service DVD's for my 1999 Ford & cannot use it now as it is time coded & the time has run out. The only way to see anything on it is to back date my computer which is a real pain. I was thinking of downloading all it contents onto my computer & then trying to trace down where the time code is & either eliminate it or update it to the present time but I do not know if I have enough expertise to try that.

Thank you again to all for assisting me with this.
Mike

 

You can get a full, not time coded copy of your service manual online from alldatadiy.com. It is subscription based, but like $60 for 5 years. That's what I do.

Did you get a code number? It is easier to look stuff up that way.

OK. Done a little digging. I believe the "Deactivator Switch" they are referring to (flash code 3) is the Brake Pressure Switch. So you might inspect the Brake Pressure Switch and wiring. This is a sensor on the brake master cylinder itself. It has a habit of leaking and causing a short in the wiring. On earlier model years, there were actually some fires, and a recall. But I believe that was fixed in 2004. My wiring diagram indicates that it was, but they aren't always accurate, and there were early and late builds in 2004.

The BPS should be fed by fuse #34. Check that with a continuity meter, then check the Brake Pressure Switch itself and the wiring. Look for brake fluid in the plug itself specifically.

 

dchamberlain - Thanks again for your reply. According to the 2004 service manual I borrowed from friend (he did not have the electrical manual that goes with the set & that would really of helped), the brake pressure switch is the switch on the brake pedal under the dash & I checked it against another & it tested out good. The diactivator switch is on the master cylinder & I already did the tests on it & it tests out fine. I also jumped it's wiring harness as well to do some of my other tests when they called for it. I will look into the online subscription you suggested as it might be what I am looking for. Thank again.

 

The switch on the pedal is called the Brake Pedal Position (BPP) switch. It is two switches in one. One switch sends a signal to the PCM, the Cruise servo and some other modules, and the other switch activates the brake lights and the signal wire to the Trailer Brake Controller plug. Functions of this switch have changed over the years prior to 2004 also.

The switch on the master cylinder is called the Brake Pressure Switch, as it measures pressure of the brake fluid. It only goes to the Cruise servo (or PCM on diesel trucks and newer trucks with Electronic Throttle Control). Apparently it is also called the Deactivateor Switch.

Regardless, it sounds like you've tested them all out.

Attached is the wiring diagram for those switches. There is another diagram, but it is for the steering wheel controls and it doesn't appear your problem is there. Also, it appears I was wrong about the fuse number. The brake pressure switch is fed from fuse #24.

 

The date code problem is simple to solve

Either reset your system date to a valid date before launching the app or use a program such as "runasdate" to launch the app and give it a valid date. I did the first for a while until I found the second.

For example, my DVD set that includes the 04-09 My is dated Oct 2007. I installed it and used the command line "C:\runasdate\RunAsDate(dot exe) 15\10\2007 C:\tso_04_09\tsobrowser(dot exe)" to launch the service DVD app. Runasdate has its own folder as does the installation folder for the 04-09 set. Piece of cake....

 

projectSHO89 - Thanks for the reply to my post. I will give it a try.

 

dchamberlain - Thanks again for your reply & the wiring diagram. The first thing I did was test all the fuses & they were all OK. Regarding the wiring diagram, I already have a copy of this diagram from the Ford guys. They gave me 3 diagrams off their online service. I asked for a copy of the wiring diagram that their Ford mechanics use off of their current service manual DVD but they said no to that one. Instead they suggested that I bring in my truck & let them diagnose & fix my problem. I then told them all the tests I did & now they want to sell me a new speed control servo for $800 & that it would take a week to get here as their is only 1 in all of Canada at a Ford garage. I told them I did not have that kind of money & that I like to diagnose & repair my own vehicles when possible. After talking to them I am thinking that if there is only 1 available then servo failures are not that common other wise there would be more available. They now think it could be the speed control servo as well so I am still going to try to find a kind person in my area whom will lend me their speed control servo so I can plug it into my truck & find out if mine is hooped or if the problem is in my wiring harness, which is still a possibility. If my servo is hooped I will then check out local auto wreckers to see if they have one at a reasonable cost or I will purchase 1 from ebay as I have seen the exact one for as little as $67 + shipping from a very reputable seller. Thanks again for your help.