john deere 455 glow plugs not working

[andrew1346]

My glow plugs are not working, the light on the dash comes on. But there is no voltage at the plugs...Looks like there is a control board on the left side of the dash. Parts book says it is a glow plug control. Kinda expensive to just throw parts at it at this point...Does anybody have any other ideas? There is a relay, it says its a engine temperature relay, not sure what its purpose it though. Or a wiring diagram maybe?? Thanks

 

[beenthere]

What is the serial number? There is a break at 70,000. Here is below test procedure and test points. Also wiring diagram too, if needed.

 

[andrew1346]

Looks like my module is dead. Power going in, nothing going out...Thanks for the help!!

Do you know what the relay on the right side above the little fuse panel is for by chance? I could not get it to do anything either...Parts sheet says engine temperature..

 

[beenthere]

Above or below the 70,000 s/n break?

 

[andrew1346]

serial # 30279

 

[beenthere]

I believe this sketch shows that it is the engine high temp relay. I'm not sure if it senses how cold it is so the glow plugs stay on longer, or just senses when the temp is above 100 deg and disengages the glow plug routine, or something else.
I'll post the theory of operation written up on the glow plug of the 455

 

[andrew1346]

Thanks very much for the info...Looks like I am buying a module, unless I can figure out the problem with the module circuit, I'll monkey around with it a little first, not out anything yet....

 

[andrew1346]

The thing that i did notice on your diagram, is that the control module looks different, my doesnt have connectors on it, it has wires soldering into the bottom that are about four inches long with connectors on the ends

 

[craig graben]

Is the glow plug module soldered to the electrical board on left side of dash?

 

[andrew1346]

The glow plug control is its own module, located on the left side right behind the radiator. Mine is fried. I replaced the melted fusable links in the harness on the right side of the engine with flat fuses. And wired in a toggle switch to turn on the glow plugs, just hold on the switch for ten to fifteen seconds, and then crank. The module is I think expensive for what it does.