7.3 99 F450 no one can figure out

[jpms]

Ok long story short and me working 15plus hrs on it now and Ford just tells to replace stuff until its fixed, I might be a little crude, sorry.
anyway, the engine dies when the wipers start to move sometimes and cold morning driving it steadily dies, yes the wiper delay kills the engine, if you unplug the wiper motor the engine will stay running so I changed out the fuses, the run/park relay and the wiper motor, still does it, Ford said change the GEM module, so installed new GEM module, still does it, bought a Matco 3.0 Determinator scanner, watched for change, nothing changes, battery voltage drops off but I am sure its the lack of rpms, Ford said it probably the alternator, unhooked the alternator, tested, still dies from wipers, the only strange thing I found is the ref voltage on the scanner is 4volts and stays 4volts all the time, so I used someone elses scanner and it shows the same voltage, I know its suppose to be 5volts and at the sensors on the engine it is between 4.995-4.998volts. So it is right at the engine. I have looked at all the wiring you can see and get your hand to, had the covers off of steering column and checked the wires, had both fuse boxes out as far as they will move and looked at the wires
arggg, I am at a loss, this weekend I am going to pull the ECM and try to figure out the power and ground inputs and pop some fuses and see if I have good current to the ECM/PCM, the IDM I would think is completely seperate from the wipers so I havent thought about how to troubleshoot it, that and its impossible to get to.
any help out there????

[jpms]

I have seen many complaints about the wipers killing the engine, searching the web, but they all seem to end with no fix or what is causing it.
can anyone help?

[Ryan Rønning]

Wish I could help but I am perplexed!

[outlawdiesel]

have you checked the switch yet.there might be a short in there or wires crossed?

[co80]

not sure what the problem is but ive heard of water behind the dash can cause this problem. i would try running some jumper wires from wiper motor to fuse relay too see if theres any difference

[Eric]

My wipers used to kill my truck. Got the cps changed under warranty and it hasn't happened since.

[jpms]

well after reading that, I slid out there and put a new cps in it, got that down pat in less than 2min, put a bunch of those in, keep a new spare in the truck, it didnt change anything

[Eric]

Originally Posted by jpms

well after reading that, I slid out there and put a new cps in it, got that down pat in less than 2min, put a bunch of those in, keep a new spare in the truck, it didnt change anything

Which type of cps did you put in it? If it was a gray one, I've heard of there being a lot of problems with those...

[nsrchofpwr]

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[jpms]

Black NAPA cps