GPR not grounding???

[fmini]

Hey all,
I have an 01 F250 49 state rig. I did the Stancor relay and replaced all the glow plugs because it's hard to start at altitude when cool and the truck was neglected by it's previous owner & I figured I would have to do this eventually anyway. Now that this is done, the problem persists. I am getting no power across the relay to the glow plugs. I checked and I am getting battery voltage to the large black/yellow wire side (full time) and the small red wire (KOEO) but it never grounds at the small orange wire. I manually grounded it with a jumper to make sure the relay is good and it is and power crossed to the large terminal on the glow plug side. Any idea where the orange wire goes or how to continue the diagnosis?

[DND58]

Pretty sure the ground is PCM controled by a number of factors such as oil temp and others. Can you start it after you manually groung it?

[fmini]

It starts fine right now but it is not cold here yet. I know it is not grounding becasue the power does not go through the relay. I can manually ground it and it works. I am wondering if the Baro or EOT could be bad or if it is only the PCM? For that matter is the Baro integral to the PCM or elsewhere on the truck?

[ClearProp]

I have the same problem. PCM not sending a GROUND signal to the orange wire on the GPR. GPR works when jumping ground to the gounding terminal. Glowplugs work to start the engine if the GPR is jumped/hotwired.

Are there any more trouble shooting aids or do I just start replacing things?

[frttrain]

I just had the same problem. (2002 f350) Replaced the PCM and fixed. Make sure the EOT sensor and air temp sensor are good before looking at the PCM.