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GP issue always on

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Old Dec 6, 2012 | 02:13 PM
  #1  
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jeffreythree
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GP issue always on

It is driving me nuts trying to track this down. Wait to start lamp stays on and glow plugs stay on all the time, disconnected one and harness lights up a test light after a 5 minute drive. I put a new relay in since the old one melted where the heat sink bit wiggles itself down to the glow plug terminal. What else to look for, the module itself? Any help would be appreciated greatly.
 
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Old Dec 6, 2012 | 04:06 PM
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From: Mi'kma'ki
try running these diagnostics Jeffery;
https://www.ford-trucks.com/forums/1...low-plugs.html
 
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Old Dec 6, 2012 | 05:14 PM
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You'll need to replace the glow plugs after you get the constant on problem fixed.
 
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Old Dec 7, 2012 | 07:22 PM
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The constant on could be cause your glow plugs are all toast from the old relay and thats a sense voltage your seeing from the controler, if you put a load on it (light bulb) see if it lights up. Or remove the white wire from the relay and see if there still on, if they arent, its the controler, if they are, look for a melted wire touching another hot wire.
 
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Old Dec 7, 2012 | 07:47 PM
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From: Charles Town, W bygod Va
Originally Posted by ifrythings
The constant on could be cause your glow plugs are all toast from the old relay and thats a sense voltage your seeing from the controler, if you put a load on it (light bulb) see if it lights up. Or remove the white wire from the relay and see if there still on, if they arent, its the controler, if they are, look for a melted wire touching another hot wire.
Taking that into consideration, I think a quick continuity test of the glow plugs is a good idea.
 
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Old Dec 7, 2012 | 08:36 PM
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Did you buy an actual glow plug relay, one that you know does NOT ground through the mounting base (isolated ground)?
 
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Old Dec 10, 2012 | 10:28 AM
  #7  
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Thanks for the suggestions and that diagnosis link. Luckily I never got around to installing my 8 new Beru GPs last winter since they are all toast now. I made sure to check for the proper relay after reading that some end up with a starter relay, and the old one may have been the original. Murphy's Law cropped up and I had to move it for the telecom company to dig a big hole where it was and the opposite now happens. Light stays on but no power to the GP harness; so I think I have a bit of wire tracing and voltage checking ahead of me while I install the GPs and make a new harness.
 
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