2004 Excursion 2wd 6.0PSD
Self Test Codes
P0703, P1536, P1780

So I have been having issues that have been piling up and I am wondering if it is the PCM.

I made a post a while back about going out into the garage and the washer fluid pump was running with the key off. I disconnected the multifunction switch and the pump was still running so I have since installed a switch between between the wires to the pump so I can turn it on and off myself.

Next issue is I lost cruise control I have a new brake light switch and a new brake pressure switch and still no cruise.

Then yesterday the tow/haul light came on and upon start up and I the button on the shifter does not toggle it on/off. I pulled apart the column last night and disconnected the harness and the light stayed on I then probed the harness leading to the PCM and after doing this the light went off. After connecting it back together the button worked I tried it before assembling the column and after and it worked. This morning upon start up the light is on again and the button is not functioning.

Maybe related or un related but several months ago I got a CEL and it was the MAP sensor. I bought a new sensor and installed it but that did not fix the issue. I installed the old sensor and the CEL went away and has not come back on?

Does it lean toward PCM or are these all separate issues? I can live with the washer pump and without cruise but driving around in tow/haul is annoying.

Thanks

 

$45 to find out...

https://www.dieseltechchatt.com/

 

Did you drive the truck under a ladder and past a black cat or something, that thing sounds vexxed

 

Curse of the 6.0

 

Low voltage??

 

They don't do 6.0 PCM stuff. I wanted them to remove PATS from my PCM, they said no.
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I know it is not the button or the harness in the shifter because I left it disconnected and then tow/haul still came back on even through it was off last time I turned the truck off.

 

Latest development. I spliced in a switch in the green wire to the washer pump. I probed this to have 12v all the time even with the key off. I am now able to run the washer pump on demand.

What I realized is the tow haul function is always on when starting the truck and the button on the shifter is inoperable. Except when I flip the switch to run the washer pump. The tow haul button works as it should until the truck is shut off. I tried disconnecting the pump but the pump had to physically run for the tow haul button to work.

Short? Where should I look?

 

Difinitely sounds like a short somewhere those two systems cross.

 

Anyone know where I can find wiring schematics for 2004 excursion with the powerstroke?