SORRY, A LITTLE LONG, BUT WORTH READING!!

I wanted to help pass along some information I found out, the hard way, about what a GPR (glow plug relay) is and is not, and what the component is actually called, on 2000-2005 Excursions. In 2000, the 7.3L Powerstroke, on Excursions, stopped using a GPR and started using a GPCM (glow plug control module), this was to meet California emissions. It is a silver, finned, aluminum module that sits on top of the motor that has a large "black" and "green" connector on it. I first ordered a GPR for the X because I had read in many forums that a glow plug issue could be caused by this. I searched and found many outlets for purchasing a GPR specifically for a 1997-2005 diesel Excursion with 7.3L. After I received it, I located a relay (solenoid), on top of the engine that had been identified thru other forums. I found out later that this was the relay (solenoid) for IAH (intake air heater). The relay that was sent to me was actually for the starter on the pass. side fender!! After doing a few hours of research I finally figured out that I could have looked for eternity and never found a GPR for my X. The component that replaced the GPR for the X is called a GPCM, and is found on top of the engine behind the fuel filter and IAH relay. I am really mad that so many mechanics I talked to and so many part outlets didn't know this!!! When I called several dealers, they tried to sell me a GPR for pre-2000 7.3L diesels from F-series!! The GPCM retails for $240, thru a dealer, off the street, I got it thru a dealer, with a mechanics discount, at cost for $125. I also found that with this GPCM, the vehicle computer will show codes if the glow plugs go bad, save yourself some time and money and get your codes read before doing any work. As a side note DO NOT GO TO AUTOZONE FOR CODE READING, it may be free but they are idiots. They code readers are not detailed enough and they have no clue on how to load test diesel batteries, they tried doing it with the batteries connected, and tested it off of the jumper battery!! Their test came up "good", I had it checked properly and found the main battery had 300CCA out of 750 and the jumper battery was 450 out of 750, both "discard" classification. I would have included pictures of the GPCM,but they don't allow attachments here. Last suggestion from me is, if you are not going to fix your own vehicles, make sure the dealer you use is familiar with the Excursion 7.3L diesel, not just any 7.3L diesels, there is a difference.

 

FYI
If anyone wants the pictures I have of the GPCM location I will email them to you.

 

Good write up but my 01 Excursion has a GPR in it.
Nick

 

Good write up but my 01 Excursion has a GPR in it.
Nick

 

Thanks for the info, JHICKEN. Is the relay in the foreground the IHA relay? This is the California-spec glow plug controller system. - GA

 

How right you are jhicken! Also GregA the box with the green and black plug look like the gpcm. That is what the dealer replaced when my #2 glowplug went bad and it burnt it out too.

 

Thanks for the response, Kev.

What I'm actually curious about is the relay in the foreground, the one that looks like the older trucks' glow plug relay. The wire protected by the rubber boot is a B+ wire, black with orange stripe, but the wire opposing it is only about 16 gauge, blue then spliced to a red with white stripe, COMPLETELY incapable of handling glow plug amperage. I'm fairly convinced at this point that this relay has nothing whatsoever to do with the glow plug system, but I'd really like to know what it's for...

 

My 03 does not have this on it as i believe it to be used for some thing else maybe some else can help you with it.

 

The relay in the picture is for the intake heater only on 7.3 Excursions. The large silver relay box works your glow plugs. I added an LED light to my gauge pod and now see how long the glow plugs actually are signaled to be on by the ECM (0-120 seconds) trigger wire to the relay inside the silver box.