I will look at this more closely when I get home (I am traveling this week). The picture I posted shows the wiring on my F450. The wire labeled non-OEM control is switched power from the dash mounted toggle switch that came with the installation kit for the Muncie PTO. It happened to have the exact same wire color as the OEM harness to make installation simple and fool proof.

I wonder if the PCM calibrations vary and some are set up with the fast idle feature while others may not? I also have two F250 trucks and they both have the blue w/yellow wire but they were hard to find. On one of the trucks I used a jumper wire to apply power to that circuit and the truck went into fast idle. However, I don't remember which F250 I was messing with. My F250 Lariat has a PTO trans installed while my F250 XLT does not. I wonder if the PCM has any way of knowing when a PTO trans is installed and then allows the fast idle feature to work? (Just making guesses at this point...) Maybe there is some other jumper wire that needs to be connected to indicate a PTO trans is installed? If so, I should be able to figure this out when I get home because I have several trucks that I can compare side by side and see if there are any differences.

Now that I think about it....I think I read somewhere that the Excursion PCM calibrations would not support the PTO enable circuits but the E series would. I'll have to try and find out where I read that and research further to see if they say anything about F250/350 models...

 

Thanks shake-n-bake, I will be waiting to see what you say. Very excited.

 

Interesting, Suscribed.

 

I tried it on my truck and it didnt work....

manual trans, checked and rechecked everything to no avail....

 

I was looking on ebay for a aux control module for my truck. There is two different kinds that I have seen, they have the one with the buttons and display which I am guessing just displays rpm, and there is one with just buttons. Is that the only difference in the two? And some of these don't come with wiring harnesses. Could I just cut off the plug under the dash and install a weather pack connector and make my own wiring harness? And finally will this module work on all 7.3 or do they have to have a certain package to work?

 

I am new to this sight and found lots of good info including this mod.

I did this mod last night on my 99 F450 cab and chasis and it worked just like Shake-N-Bake says but it took 2 tries. The first time I was tied into the wrong side of the harness. Then I found the other end of the light blue wire and it worked.

 

Thanks for posting this info.
Do you happen to have a photo of the wire you used that was successful?

 

It was the same light blue w/yellow that you used just there were 2 of them that were both dead ended in the general location. It took a little digging to find the end that worked.

 

Suscribing - have an 00 F250 & an 02 F350 I'd like to try this on.

Going to dig under the dash on the 250 to see if I can find the wires mentioned above.

 

I dug out the other wire tonight and tried them both. Still no worky, I sure wish it would though.

Shake-N-Bake, I plan on giving you a call tomorrow hopefully.

 

It does take a second or two for the idle to come up when you put power to it.

I hope you can get it to work because it is really nice to be able to to warm up your truck truck so fast.

 

How long is long? I am just curious, maybe I haven't waited long enough.

 

It was 2-3 seconds before it started to go up. It also goes up slowly. Not like a light switch.

My wires were also dead ended from the factory. I did not need to cut anything.

 

Didn't work on mine, either.(2000 auto) I tried both B/Y wires and even tried adding a light in case it needed to to see some draw. I didn't try using the B/P for since the working pic didn't use it.

All three wires and the pass through's where very easy to find and not bundled.

 

Ok, I had some time this weekend to research a little further. I looked at both of my F250 trucks. On each truck, I found a pair of blue with yellow stripe wires. The first wire was buried in the wire harness bundle that comes from the OBDII connector and the second wire was found in the wire harness bundle that is routed to the AIC connector.

On both trucks I found two labels on the wiring harness bundle that feeds the OBDII connector. One labels is silver and reads "Customer Access Circuits" and the other label is white and reads "Power Take Off Circuit". On my '99, the white PTO label was wrapped around the OBDII wiring harness bundle and on my 2000 it was only wrapped around the blue w/yellow wire. Minor difference but I noted it anyway.

Applying 12v power to the blue with yellow wire DID cause the engine to fast idle on my 2000 F250 but did NOT up the idle on my '99 F250. My 2000 F250 also has a PTO 4R100 transmission but there is no PTO installed. At this point I can only suppose two possibilities. A) the PTO enable (fast idle) feature is dependent on PCM programming or B) the PCM is able to determine if a PTO transmission is installed and then makes that circuit active. If either is true, then the PTO circuit should be active for all manual transmission vehicle since I believe they all have PTO capabilities. Does anyone have a manual trans and be willing to check and see if this works on their truck?

The wire that works is the wire found in the OBDII wiring harness bundle. There also is a identical wire in the AIC wiring harness bundle but that one does not work. In fact, if you gound that wire when the engine is fast idling then the engine will resume normal idle speed until you un-ground that wire. Not sure what is going on there but that is what I found in my 2000 F250 and 2001 F450.

Also, when applying power to the proper Blue with yellow stripe wire, the only thing that causes the PCM to fault back to normal idle speed is depressing the brake pedal. The Parking Brake does NOT have to be set and you can rev the engine as well. In addition, after about 6 seconds of fast idle, the PCM locks the torque converter. I also noted that the Ford AIC module does NOT lock the TC under any circumstances.

Lastly, I used my AE on my F250 and F450 when setting the engine to fast idle and set the Live Data Meter to the "Power Take Off Status" setting. The default value is 0 (zero) but it did not change when the engine went into fast idle. I expected it to change to a value of 1 (one) but it did not. I tried both ways, using the 12v to blue wire switch or the Ford factory AIC controller...neither method caused the value to change as monitored by AE.

My '99 F250 does have a PHP chip so I suppose that could be the reason why the fast idle doesn't work. I did make sure the dial was set to "stock" setting but it's a modified stock calibration so I guess the only way to check for sure is to remove the chip and see if the blue wire works. I might try that sometime later when it stops raining.

I did take some time to compare the fuse panels on all three trucks to see if there was a fuse that might have been missing. Fuse location #18 had a fuse in that spot on the 2000 F250 and the 2001 F450 (the two trucks where the fast idle wire functioned properly) while my '99 F250 did not have a fuse in that spot. I installed a fuse but it didn't make any difference...meaning the fast idle wire still didn't work on the '99.

At this point I am a bit stumped. Seems like the fast idle feature might be hit and miss for each particular vehicle. I am really curious of anyone with a manual trans can try out the fast idle wire and see if it works on their vehicle. There is a possibility that the parking brake might need to be set for manual trans vehicles so that is something to keep in mind.