well i have been having issues with glowplugs working sometimes they do and sometimes they dont what would this be the controller?the apparently arent working this morning which means no work until i let it sit plugged in for a while

 

I think it's the controller under the relay.
Mine cycles for about 1 second no matter how cold it is so I added the grounding jumper wire bypass from the relay to a switch on the dash.

 

what do you mean a grounding jumper wire?

 

You just unhook the white wire from the rear outside post on the relay, and run a wire from it, to a pushbutton switch, and then to ground. I guess the glow plug relay energizes by completing the ground, so it's easy to run a switch for it.

 

so it just gives it a better ground?i already ran the ground wire to the battery.should i run a power wire from a push button instead you thing.oh and what the crap is the black wiring connector at the bottom of the controller?

 

ok so what is the white wire for?the ground wire i ran to the battery is from the ground on the bottom of the unit on the valve cover.so i would take the wire off and run a wire from it to a push button then to a chassis ground?why couldnt i just run a ground to the battery from the white wire?,and leave it connected to the unit.

 

OK!
You know how, head lights, or the starter is grounded all the time and you add power to get it to work?

The Glow Plug relay works the other way around.
It has power all the time and no ground, so when you add a ground, it completes the circuit and the Glow Plugs warm up.

Be careful though.
Hold the button too long and they burn up, swell up so they can not be removed from the head and then stop working.

 

ahhh ok and the white wire is the ground to activate the controller.i got ya now.lol

 

so cold mornings just hold it for 10 seconds and fire it up correct?will my WTS light stay on as long as the buton is held i assume?

 

Last winter I DID NOT GET IT!

My truck sat for most of a week waiting for the temp to rise above 0 degrees and to get into the teens with an, um, well, ok, an idiot attempting to add 12V to the grounding lug!

Before this winter set in, I added the glow plug circuit to a button on the dash next to "but not too close to" the starter button that itself is powered from the injection pump power.

Below 20 degrees my ignition gets so damn stiff, I almost cant turn it to start the damn truck, or stop the starter from getting stuck on!

I can also shut off the engine while in gear without the key moving to have a faster "in gear" shut down and start up when shutting down at long lights to do the hyper-mile thing.

Oh, I also added head light relays between the head lights and batteries.
All my head lights are powered with less than 12 inches of combined ground and power wire each and are so bright, people think my old rust bucket truck has its high beams on until I flip them on and blind them!

 

so i dont even use the white wire correct?

 

You could just add an additional ground wire.

There is one nut holding a large flat metal connection and it's pointing to the drivers side front where the white wire is connected.

You can also connect a D.V.O.M and you will see 0V with the key on while the wait to start light is on, then it goes to 12V when the light goes out.

It also shows no voltage when the glow plugs show voltage.

 

Here you go.



The two small terminals on the relay are the trigger circuit.
The ignition terminal has power supplied by the ignition switch when the key is ON.

The black ground wire attaches to the intake/valve cover to supply a ground to the controller.
When you turn the key on, power to the ignition terminal and the controller through the small red wire in the picture on the ignition terminal test the resistance of the glow plugs.

If the resistance tells the controller the glow plugs are cold, the controller then sends a low (ground) through the white wire to the relay, completing the trigger circuit to energize the relay and heat the glow plugs.

So if you send a ground condition to the white wire terminal when the key is ON, the relay will close.

The resistance sensing to tell the glow plugs are cold is why the new style controller likes for the glow plugs to be within .5 to 1 ohm's resistance.

Yes a glow plug that shows 4 ohms resistance will still heat, but it is confusing the controller and making it think the glow plug is warmer than it actually is, resulting in lower glow times or not functioning at all.

Next problem area, this is a 6.9 wiring harness, but the 7.3 has a connector almost like it.(the one circled in red)



The large AWG wires, orange at the bottom of the connector in the picture would be either yellow or tan on a 7.3 harness.

Check the connector on the end that has the two large AWG wires.
Any indication it has been hot, discolored or melted, means there is corrosion in the connector.

Since those wires are power to the glow plugs on the 6.9 system and power to the glow plug relay on the 7.3 system, a less than perfect connection there also affects the glow plug heat cycle/time.

That connector is not available, if it is not in perfect condition splice the two large wires around the connector so the glow plugs/relay are/is getting full power.

Word of caution, on the new style glow plug system those wires run straight to the battery positive terminal, so big sparks if you short it out while working on it.

 

ok so doing the push button will energize the controller.but i may still have another issue and it may not help.correct?

 

Doing the push button will completely bypass the controller altogether. But you run the risk of burning out your glow plugs if you hold them on for too long. So care has to be taken when using the manual push button, but its not rocket science.

I'm dealing with a controller that works when it wants to, so at times I have to manually ground the solenoid to warm the plugs. If I can't find a replacement controller at a decent price, I'll end up have to add the manual switch also.

AB