Glow plug question (1 Viewer)

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I have a 78 BJ40. The glow plugs are powered through a starter solenoid. That being said, the power wire to it was melted today. The solenoid has no continuity. Does anyone know what it should be?
 
I have a 78 BJ40. The glow plugs are powered through a starter solenoid. That being said, the power wire to it was melted today. The solenoid has no continuity. Does anyone know what it should be?
you might want to cross post this into the Diesel/24 Volt section
 
You say they're powered through a "starter solenoid".
I assume that means that a PO added a Wilson switch on the dash, which triggers the solenoid and that switches power to the glow plugs (fairly common mod, although usually a beefy relay would suffice).
Which wire is actually melted? The power wire from the battery To the solenoid?
That might suggest that one of your glow plugs has blown (short circuit) and overloaded the wire - disconnect the bus bar and test the resistance of each plug to ground.
You say there's no continuity.. does it click when you press the button?
A photo of the setup will help a lot.
 
You say they're powered through a "starter solenoid".
I assume that means that a PO added a Wilson switch on the dash, which triggers the solenoid and that switches power to the glow plugs (fairly common mod, although usually a beefy relay would suffice).
Which wire is actually melted? The power wire from the battery To the solenoid?
That might suggest that one of your glow plugs has blown (short circuit) and overloaded the wire - disconnect the bus bar and test the resistance of each plug to ground.
You say there's no continuity.. does it click when you press the button?
A photo of the setup will help a lot.
I'll get a photo tomorrow. And no it doesn't click after replacing the melted wire from the battery to the solenoid.
 
Sounds like the solenoid might be blown.
It may have shorted out inside, and then blown the fuse for the trigger feed (wherever that comes from -
Check your fuses).
Probably worth disconnecting the solenoid to avoid a repeat
 
Sounds like the solenoid might be blown.
It may have shorted out inside, and then blown the fuse for the trigger feed (wherever that comes from -
Check your fuses).
Probably worth disconnecting the solenoid to avoid a repeat
Thanks
 
My system has that Grey wire that I used to replace the burnt one going to the solenoid pictured. Then a wire from a button on the dash going to the terminal. And a wire on the other side from the power going to the glow plug rail.

20241019_172926.jpg
 
I see it's insulated, but it's capable of carrying, what, 50Amps? (half a kilowatt).
If things go wrong (e.g. a sharp metal edge rubs through the insulation) that could quickly become a fire... Consider adding a fuse close to the battery at some point :)
 
If that feed wire melted before, it could be that the solenoid got welded closed and it stayed on for a long time. It happens when the inrush current to the glow plugs is too high.
You could try wiring the "glow controller" in series if it isn't already (the glow thing on the dash under the headlight knob). This will increase your cold resistance and reduce the inrush.
Otherwise, connect a lamp to the output of the solenoid so that you at least know when it gets stuck on...
 
It was a stuck solenoid. It works great now
Check the glow plugs are correct voltage as spec'd in the manual, and wire in the "controller" in series to reduce the current (if it isn't there already).
Be careful if you're buying a new one - there are two variants, but the part numbers have been merged - work out if you need a thick or thin coil.
 

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