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Yes...it can be done
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Discussion Starter · #1 · (Edited)
I would like to thank Dustoff for attaching this PDF in a previous thread. It is a pinout of the 03 Cobra PCM.

http://www.modularfords.com/attachment.php?s=&postid=39352

After looking at the PCM pinout, I grabbed a highlighter and marked up the I/O that I found interesting.

Pin 21: Crankshaft position sensor
Pin 45: Supercharger bypass solenoid
Pin 46: High speed fan control relay
Pin 63: Fuel rail pressure transducer
Pin 66: Cylinder head temperature sensor
Pin 82: Charge air cooler pump relay
Pin 89: Throttle position sensor input

Questions:

1Q. If I were to wire switches to turn on the high speed fan, and the intercooler pump, would I have to diode-isolate the PCM, to prevent sinking voltage into the PCM?

1A. No, just attached a splice to the correct wire and run to a switch, then ground the switch. To be on safe side I installed a 10amp fuse between PCM wire and switch. No problem ! On Lightning or Cobra. -Contributed by Dustoff

2Q. Is there an electronic fuel pressure gauge that can be calibrated to use the transducer on Pin 63?

3Q. Is there a temperture gauge that can be calibrated to use the transducer on Pin 66?

4Q. Has anyone spliced into Pin 45 to disable the bypass solenoid with a switch?

I use Pin 21 for a 99+ tach adapter for my car, and Pin 89 for a TPS switch.
 

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03Steve said:
I Questions:

1. If I were to wire switches to turn on the high speed fan, and the intercooler pump, would I have to diode-isolate the PCM, to prevent sinking voltage into the PCM?
No, just attached a splice to the correct wire and run to a switch, then ground the switch. To be on safe side I installed a 10amp fuse between PCM wire and switch. No problem ! On Lightning or Cobra.

2. Is there an electronic fuel pressure gauge that can be calibrated to use the transducer on Pin 63?
Don't know sorry.

3. Is there a temperture gauge that can be calibrated to use the transducer on Pin 66?
Again don't know

4. Has anyone spliced into Pin 45 to disable the bypass solenoid with a switch?
Have not heard of that, just unplug or bypass with vacuum T

Thanks,

Jon L
 

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Yes...it can be done
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Discussion Starter · #3 ·
Pin 46: High speed fan control relay, control
Pin 82: Charge air cooler pump relay, switched power, output


So the PCM does not provide 12VDC to power the fan, it only provides a ground point. For the pump, it would provide 12VDC to drive the pump.

Is this the difference between the "control" and "switched power, output" classification?
 

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I am not that familiar with the 03 yet, but on the 96 Cobras, splicing into the fan controller wire caused a few CCRM's to go out. I had this happen twice on my car and talked to others during that time that had the same faliure after doing this mod. Just wanted to throw in my experience.
 

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Yes...it can be done
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Discussion Starter · #5 · (Edited)
If a CCRM is a relay within the PCM, I offer this for protection:

Get a two position switch from Radio Shack. Cut the wire between the fan and the PCM. Connect the fan side of the wire to the top side of the two position switch. On one side of the bottom of the switch, connect a new wire lead to ground. On the other side of the bottom of the switch, connect the wire that is coming from the PCM.

The fan will continue to operate normally with the new switch in its off position. :D
 

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Yes...it can be done
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Discussion Starter · #6 ·
So, what about the charge air cooler pump relay (Pin 82, intercooler pump). Does the wire to/from the PCM require 12VDC or ground to turn on the pump? I know the X2C guys have done this.

I like the idea of running the fan on high speed with the intercooler pump circulating while waiting for the staging line to shrink.
 

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03Steve said:
So, what about the charge air cooler pump relay (Pin 82, intercooler pump). Does the wire to/from the PCM require 12VDC or ground to turn on the pump? I know the X2C guys have done this.

I like the idea of running the fan on high speed with the intercooler pump circulating while waiting for the staging line to shrink.
Both pin 46 and pin 82 ONLY require a ground to kick on relay. I ran wire to a fuse for protection fuse to a switch and switch a ground. Mounted in the console in front of shifter below the TC button. Works fine !

Its been wired for almost a year with zero problems. Do Not Run a 12V source to those pins you will be asking for trouble.

Jon L :)
 

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Yes...it can be done
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Discussion Starter · #8 ·
Thanks Jon! Good stuff.... :D
 

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Bluesmobile
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I have these mods also, plus an electric water pump. They all cool the engine down fairly fast. But be warned, they will flatten your battery in no time at all.
I has happened to me twice. Both times while the car was on the dyno.
The battery Ford puts in these car is strickly enough to get it out the door at the assembly plant, that's it. It has almost no reserve capacity.

I plan on bringing something to charge the battery with next time and run it the entire time for the dyno.

Dana
 
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