mchan68

If you find yourself needing to order up an engine harness or glow plug harnesses, I have determined the easiest way to identify whether you have a mid/late build, or late/late build 2004 engine. For starters, if your build date is earlier than September 29th, 2003, you should consider yourself the owner of a 2003 truck, when it comes to ordering any and all engine parts.

However, those of you with trucks with build dates after September 29th, 2003, things can get a little tricky when it comes to determining the correct engine harness and glow plug harnesses. Here is how to do it. Look at your ICP sensor on the passenger side valve cover. Pay attention to how the GPCM is bolted up to the bracket that secures to the valve cover. If you happen to have it secured in a manner similar to a 2003 engine, you have a mid/late build 2004 engine. As such, your engine uses engine harness Ford part number 4C3Z-12B637-AA (Navistar ID# 1844262C93), to be used with glow plug harnesses part numbers 4C3Z-12A690-AA (Navistar ID# 1845915 C9) right side, and 4C3Z-12A690-BA (Navistar ID# 1845793 C9) left side.

If you have your GPCM mounted on the bracket, identically to the way it is on 2005 and later engines, you have a late/late build 2004 engine. As such, your engine uses engine harness Ford part number 4C3Z-12B637-CA (Navistar ID# 1846377C92), and glow plug harness Ford part numbers 4C2Z-12A690-AB (Navistar ID# 1845794 C9) right side, and 4C2Z-12A690-BA (Navistar ID# 1845695 C9). Notice, the right side glow plug harness part number is also identical to that, that is used on '05 and later engines.
 

In answer to your question, yes I do. This sounds EXACTLY like one I had towed into me a while back. I couldn't communicate with IDS. After ohming pins #6 and #14 and getting 120 ohms, confirming there was a module offline, it turned out to be a green deathed network wire under the driver's door opening scuff plate. THAT, took a lot of my time to pinpoint. Something else you need to be aware of, is if this vehicle doesn't have the factory trailer brake control option, the connector to it is still present and plugged into the blank plastic trim piece. In that connector is also the HS CAN + and HS CAN - circuits dead ended into it. I also had an issue a long while back where an aftermarket installer had installed an aftermarket trailer brake controller into this circuit by snipping the wires off this connector cutting off the SJB out of the equation in the process, and in turn causing a no-crank no-start that had to be towed into me.