2000 excursion not activating GP or IAH

[swasenko]

I have a 2000 Excursion and it is not activating the glow plugs or the intake heater. I verified the glow plug controller and intake heater relay were both working properly. There is no signal coming from the signal wires to the glow plug controller or the intake heater relay.

I'm wondering if it's just a bad PCM or if something could make it flake out, like a bad ambient temp sensor. If the temp sensor thinks it's really warm outside then maybe it is not activating the two?

[NoRalPh]

OK First, don't look for the AIH to come on, they Rarely do and not important to starting.

Second, the GPR is regulated mostly by the EOT (Engine Oil Temp) sender to know GPs are needed.

The PCM sends a ground path to the GPR to activate it. Be sure it's doing that by removing the two sm terminals from the relay. One will have 12v in it, the other should switch to ground for as long as the PCM thinks wants the GPs on (this varies with temp and has NOTHING to do with the WTS light.

And yes, once the PCM is satisfied that the EOT is warm enough, even though the WTS comes on, it doesn't send that ground path to the relay.

If the relay checks-out (the most common cause) what's left is the EOT sensor, the PCM, or the wiring & plug between them (both from the sensor & to the relay, with the PCM in between)

[swasenko]

I have an excursion so it has a glow plug controller, not a relay. I did unhook the connector and checked the siganl wire for a switch to ground. There is none. I can check it at the 42 pin connector I guess next. I wanted to know what else to check. I guess after that I can try the oil temp sender. I am getting a reading at my edge tuner for oil temp and it seems to be tracking fine. Is there a seperate pcm sender?

[Meat_Puppet]

Originally Posted by swasenko

I have an excursion so it has a glow plug controller, not a relay. I did unhook the connector and checked the siganl wire for a switch to ground. There is none. I can check it at the 42 pin connector I guess next. I wanted to know what else to check. I guess after that I can try the oil temp sender. I am getting a reading at my edge tuner for oil temp and it seems to be tracking fine. Is there a seperate pcm sender?

I'm confused. I have a 2000 Excursion as well, and I don't know of this "glow plug controller" you speak of. I have a relay. Maybe you could post up a pic?

[swasenko]

All of the excursions have glow plug controllers and not relays as far as I know. You might be looking at the intake heater relay. The gpc is behind that on the passenger valve cover. It has two plugs coming out of it. a green and a black one the are around 8-9 wire plugs.

[Meat_Puppet]

I actually tried to edit that response after I did some searching cuz i realized my dumbass was talking about the AIH relay LOL! Sorry to clutter your thread. I actually have to purchase a GPCM as well, as I had 6 out of 8 GP "go bad". After i checked them I realized it was the GPCM.

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[swasenko]

That's ok. I have a brand new one if you want to buy it. $140 shipped to you. It's brand new in the box with receipt and warranty from ford.