Confused -- pulling the fender to get to the PCM? Or ICM?

 

Fenderwell.

 

I also have a 99 7.3L manual.

The PCM is inside the cab, left of the clutch pedal. (I installed a hydra to it)

No reason to take the fender off.

The Injector Driver Module (which I have seen called the Injector Control Module (ICM)) is in the fenderwell.

 

Might be related to current error codes, P0470 and P0478???
Back pressure tube removed cleaned and inspected and new EPC sensor installed with no change in error status.

P0470 is usually a wiring problem - I had to buy a new pigtail for the Exh Back Pres. Sensor.

Did you clear the code after you did the work? You didn't mention it.

 

P0470 is usually a wiring problem - I had to buy a new pigtail for the Exh Back Pres. Sensor.

Did you clear the code after you did the work? You didn't mention it.

Yes I did clear the code and checked the voltages on the connection by back probing. Code only shows up on Forscan, CEL is not on.

It may be possible that one of my computers is getting wonky and sending out garbled info.

Bottom line is I'm trying to find out where the glow plug solenoid gets it ground signal from. PCM, ICM, or PBR and what color the wire is and what pin it connects to.
Pulled the PCM? under the dash and checked for corrosion or obvious problems sprayed connectors down with cleaner and reassembled with no change.

 

Doesn't show a 7.3L

 

Engine Controls

 

 

I believe the glow plug relay is grounded by the mounting.

I am wrong

 

Glow plug relay is not grounded to the vehicle the computer supplies a ground to turn it on.

 

I am corrected.

 

Not in Ford's Wiring Diagrams.

What diagrams are you looking at?

The PCM provides the ground to the relay and it gets its power from the key on. It has always been this way. If you look at a 7.3 Powerstroke PCM pin out you will find the pin that supplies the ground. On the 94-97's it is on pin 101. I just looked on line and it is the same pin for the 99+ year of truck

The relay is a case isolated relay in that if you just supply power to the relay coil it will not activate, it needs that ground signal from the PCM. There were some problems a few years ago with a familiar parts store selling case grounded relays as glow plug relays. Once they were installed the relay would stay on as long as the key was in the run position.

 

Thanks, @Bugman. @flmeade -- proper page diagram from the 1999 F350 Ford Wiring Diagram

 

Where did you get that book?

 

It is a relay and not a solenoid

 

My owners manual shows no relay for glow plugs. Checked it this morning.

 

The main difference between Relay and Solenoid is, Relay is a switching device that switches or routs the electrical current or signal whereas the solenoid is an electromagnetic actuating device that pushes or pulls a shaft or any metallic arrangement much like what would be on a starter. They are basically the same, using a low current wire to activate a heavy current appliance or in this case the glow plugs.

I haven't looked at a owners manual in quite a while but I have never seen any reference to the glow plug relay in on. They just tell you to wait until the Wait To Start light goes out before starting.

On the manual it looks like a Helm manual. They have been out of print for sometime now but you can find them on Ebay every now and then. If you do make sure that you get the EVTM, and Mechanical manuals. You can also find CD's on Ebay for 1/10 of the cost of what you would pay for a Helm manual for these trucks, and quite likely you can find one today and download it to your computer or have the CD sent to you.