Notices
1999 - 2003 7.3L Power Stroke Diesel  
Sponsored by:
Sponsored by: DP Tuner

Glow plug relal

Thread Tools
 
Search this Thread
 
Old Jan 26, 2011 | 07:59 PM
  #1  
jeff wilson's Avatar
jeff wilson
Thread Starter
|
Freshman User
Joined: Apr 2005
Posts: 35
Likes: 0
From: Phoenix,N.Y
Glow plug relal

I don't have any control power to my glow plug relay, However there is 12 volts to the supply side ( the big terminal) . I have checked all the fuse's and they are all good. Any idea's Thanks Jeff.
 
Reply
Old Jan 26, 2011 | 08:34 PM
  #2  
F350-6's Avatar
F350-6
Post Fiend
Joined: Mar 2007
Posts: 26,966
Likes: 50
From: Texas
Not sure what you mean by control power. The 12v supply side is constant from the battery. When the key is turned on, the PCM sends a ground signal to one of the small posts to activate the relay and send the 12v out the other large post to the glow plugs.

What I would consider the control, would be the ground signal.
 
Reply
Old Jan 26, 2011 | 08:51 PM
  #3  
PaysonPSD's Avatar
PaysonPSD
Post Fiend
Joined: Nov 2007
Posts: 9,549
Likes: 14
From: Payson, AZ
Make sure you are checking the GPR and not the AIH (Air Intake Heater) relay.

If you have 2 relays that look the same the one closest to firewall is the GPR.

Also be sure your truck has a GPR and not a GPCM (Glow Plug Control Module). Trucks built for the California market and all Exursions have a GPCM.

Cali truck & EX:

 
Reply
Old Jan 27, 2011 | 04:05 PM
  #4  
jeff wilson's Avatar
jeff wilson
Thread Starter
|
Freshman User
Joined: Apr 2005
Posts: 35
Likes: 0
From: Phoenix,N.Y
Originally Posted by F350-6
Not sure what you mean by control power. The 12v supply side is constant from the battery. When the key is turned on, the PCM sends a ground signal to one of the small posts to activate the relay and send the 12v out the other large post to the glow plugs.

What I would consider the control, would be the ground signal.

Right i dont have the 12 volts to or at the small post to activate the relay or to allow 12 volts to the glow plugs.
 
Reply
Old Jan 27, 2011 | 04:59 PM
  #5  
tdpower's Avatar
tdpower
Postmaster
Joined: Dec 2008
Posts: 3,340
Likes: 2
The pcm activates the gpr with a ground signal on one of the small posts. The other small post is vpwr supplied from the pcm as well. I attached a wiring diagram. What problems are you having with the truck? Just cold start issues? Does it start when it's plugged in?
 
Attached Images
File Type: pdf
7.3_2000 schematic.pdf (840.1 KB, 202 views)
Reply
Old Jan 27, 2011 | 07:17 PM
  #6  
tdpower's Avatar
tdpower
Postmaster
Joined: Dec 2008
Posts: 3,340
Likes: 2
After looking at the diagram again it looks like vpwr is an input to the pcm. The pcm relay appears to be providing the vpwr to gpr. I would check for key power, B+, and ground with the pcm relay unplugged key on and off.
 
Reply
Old Jan 27, 2011 | 07:59 PM
  #7  
thordehr's Avatar
thordehr
Senior User
Joined: May 2010
Posts: 396
Likes: 3
From: Los Angeles, CA
I've heard a lot about Cali trucks having a GPCM instead of a GPR. I have a 1999 Cali truck and I have a GPR which actually I'm glad about since I can get the Stancor relay someday if I need/want it:


Is my truck an unusual build?
(don't mean to hijack the thread but maybe this will bring out some more info concerning GPR's and GPCM's?)


Originally Posted by PaysonPSD
Make sure you are checking the GPR and not the AIH (Air Intake Heater) relay.

If you have 2 relays that look the same the one closest to firewall is the GPR.

Also be sure your truck has a GPR and not a GPCM (Glow Plug Control Module). Trucks built for the California market and all Exursions have a GPCM.

Cali truck & EX:

 
Reply
Old Jan 27, 2011 | 08:02 PM
  #8  
BigAlsPSD's Avatar
BigAlsPSD
Post Fiend
Joined: May 2009
Posts: 5,470
Likes: 3
From: Pea Ridge, AR
Club FTE Gold Member
What year is your truck? I believe the Early '99's didnt have GPCMs
 
Reply
FTE Stories

Ford Trucks for Ford Truck Enthusiasts

story-0

This Hennessey Takes the Expedition Tremor's Off-Roading Capability to the Next Level

 Verdad Gallardo
story-1

Top 10 Fords at 2026 Carlisle Ford Nationals

 Joe Kucinski
story-2

3 Best / 3 Worst Parts of Modern Ford Ownership

 Brett Foote
story-3

10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches

 Pouria Savadkouei
story-4

Every 2026 Ford Engine Explained

 Brett Foote
story-5

10 Ugly Ford Trucks That We Still Kinda Love

 Joe Kucinski
story-6

10 Things Every Truck Owner NEEDS (2026 Edition)

 Michael S. Palmer
story-7

Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath

 Verdad Gallardo
story-8

Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer

 Joe Kucinski
story-9

2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)

 Brett Foote
Old Jan 27, 2011 | 08:08 PM
  #9  
tdpower's Avatar
tdpower
Postmaster
Joined: Dec 2008
Posts: 3,340
Likes: 2
Originally Posted by thordehr
I've heard a lot about Cali trucks having a GPCM instead of a GPR. I have a 1999 Cali truck and I have a GPR which actually I'm glad about since I can get the Stancor relay someday if I need/want it:


Is my truck an unusual build?
(don't mean to hijack the thread but maybe this will bring out some more info concerning GPR's and GPCM's?)

I believe it's called a gpr shunt or something like that. I'll try to look it up for sure. 99's can be weird trucks.
 
Reply
Old Jan 27, 2011 | 08:12 PM
  #10  
thordehr's Avatar
thordehr
Senior User
Joined: May 2010
Posts: 396
Likes: 3
From: Los Angeles, CA
The shunt is the metal strap bridging some of the contacts. There's mention of it in the Stancor instructions.
 
Reply
Old Jan 27, 2011 | 08:25 PM
  #11  
tdpower's Avatar
tdpower
Postmaster
Joined: Dec 2008
Posts: 3,340
Likes: 2
Originally Posted by thordehr
The shunt is the metal strap bridging some of the contacts. There's mention of it in the Stancor instructions.
Sounds right then. I think it is for the pcm to monitor the glow plugs or relay. Probably something to do with smoke. Now you guys have smog checks.
 
Reply
Old Jan 27, 2011 | 08:40 PM
  #12  
thordehr's Avatar
thordehr
Senior User
Joined: May 2010
Posts: 396
Likes: 3
From: Los Angeles, CA
The smog checks for me are actually pretty easy since I don't have to have a Catalytic Converter. It's really just a visual inspection by people that don't know anything about diesels and a PCM scan for any outstanding codes. Still a waste of my money and time though.
 
Reply
Old Jan 27, 2011 | 09:01 PM
  #13  
tdpower's Avatar
tdpower
Postmaster
Joined: Dec 2008
Posts: 3,340
Likes: 2
Originally Posted by thordehr
The smog checks for me are actually pretty easy since I don't have to have a Catalytic Converter. It's really just a visual inspection by people that don't know anything about diesels and a PCM scan for any outstanding codes. Still a waste of my money and time though.
I found a pic of the shunt + gpr and how it is wired up. Kevin on dieselstop..
 
Attached Images  
Reply
Old Jan 27, 2011 | 09:02 PM
  #14  
countrycar's Avatar
countrycar
Posting Guru
Joined: Mar 2007
Posts: 1,425
Likes: 9
Originally Posted by PaysonPSD
Make sure you are checking the GPR and not the AIH (Air Intake Heater) relay.

If you have 2 relays that look the same the one closest to firewall is the GPR.

Also be sure your truck has a GPR and not a GPCM (Glow Plug Control Module). Trucks built for the California market and all Exursions have a GPCM.

Cali truck & EX:

I think it may have something to do with the year. My 99.5 Cali truck has 2 Relays. I think they started the Gpcm in 2000 on.
 
Reply
Old Jan 28, 2011 | 04:35 PM
  #15  
jeff wilson's Avatar
jeff wilson
Thread Starter
|
Freshman User
Joined: Apr 2005
Posts: 35
Likes: 0
From: Phoenix,N.Y
Originally Posted by tdpower
The pcm activates the gpr with a ground signal on one of the small posts. The other small post is vpwr supplied from the pcm as well. I attached a wiring diagram. What problems are you having with the truck? Just cold start issues? Does it start when it's plugged in?

This diagram is the same for a 2001 F-350?
 
Reply



All times are GMT -5. The time now is 11:15 PM.

story-0
This Hennessey Takes the Expedition Tremor's Off-Roading Capability to the Next Level

Slideshow: The VelociRaptor Expedition gains a lift, upgraded suspension, Brembo brakes, and trail-ready equipment while retaining the stock 440-horsepower EcoBoost V6.

By Verdad Gallardo | 2026-06-12 11:01:55


VIEW MORE
story-1
Top 10 Fords at 2026 Carlisle Ford Nationals

Slideshow: Top 10 Fords at 2026 Ford Nationals

By Joe Kucinski | 2026-06-09 11:10:08


VIEW MORE
story-2
3 Best / 3 Worst Parts of Modern Ford Ownership

Based on years of owning multiple modern Ford products.

By Brett Foote | 2026-06-09 10:53:36


VIEW MORE
story-3
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches

SPONSORED: From muddy boots to rain-soaked cargo, these upgrades address some of the most common frustrations Ford truck owners face every day.

By Pouria Savadkouei | 2026-06-08 18:50:34


VIEW MORE
story-4
Every 2026 Ford Engine Explained

Here's everything you need to know about every Ford engine available for the 2026 model year.

By Brett Foote | 2026-06-05 12:58:01


VIEW MORE
story-5
10 Ugly Ford Trucks That We Still Kinda Love

Slideshow: 10 ugly Ford trucks that we still kinda love.

By Joe Kucinski | 2026-06-03 09:51:16


VIEW MORE
story-6
10 Things Every Truck Owner NEEDS (2026 Edition)

Slideshow: the best gifts for dads & grads

By Michael S. Palmer | 2026-06-03 15:43:58


VIEW MORE
story-7
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath

Slideshow: Called the Fortress, the 850-horsepower pickup combines Raptor underpinnings with military-inspired features, survival equipment, and a starting price of $285,000.

By Verdad Gallardo | 2026-06-03 11:38:36


VIEW MORE
story-8
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer

Slideshow: 10 most expensive Ford trucks ever sold on Bring a Trailer.

By Joe Kucinski | 2026-05-27 16:24:34


VIEW MORE
story-9
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)

Here's everything that has changed for the latest model year.

By Brett Foote | 2026-05-27 16:17:28


VIEW MORE