wires getting very hot??????????
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Joined: Apr 2006
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wires getting very hot??????????
1991 ford f-250 7.3 diesel. there are two wires that come from the solenoid on the fender and go to the glow plug solenoid on the back of the intake. these two wires will get so hot that they melt the insulation on the wires. i replaced the wires and it still does it. what would be causing it to short out and get so hot? could it be the glow plug solenoid? and if so how do i check it? these wires are yellow and they connect to the hot side of the solenoid on the fender.
Tuned
Joined: Oct 2004
Posts: 250
Likes: 6
From: new york
This is a common problem, those yellow wires are the wires that go directly to the glow plugs. Its rare to see a Ford that doesnt show some heat discoloration at the connector, most have some insulation burnt off.
The best way to fix this is to soilder them together, if you pull the yellow wires out of the loom a few inches on both sides of the connector you can get enough slack to get them together.
Cut both ends as close to the connector as possible, strip back the insulation, get a couple 12 gauge butt connectors, remove the plastic insulation around them, crimp the connector to the wire then soilder the connector, then wrap with electrical tape or you could use shrink wrap but make sure you put it on before you crimp the wires together.
These wires carry alot of current and since electrons (current) flows on the outside of the wire strands(thats why they use stranded wire more surface area as opposed to solid wire)when you use just a butt connector with the basic mechanics crimp tool that just squeezes two sides of the connector, you dont get good contact between all the strands and that limits the flow through the connector causing heat. Clear as mud!
The best way to fix this is to soilder them together, if you pull the yellow wires out of the loom a few inches on both sides of the connector you can get enough slack to get them together.
Cut both ends as close to the connector as possible, strip back the insulation, get a couple 12 gauge butt connectors, remove the plastic insulation around them, crimp the connector to the wire then soilder the connector, then wrap with electrical tape or you could use shrink wrap but make sure you put it on before you crimp the wires together.
These wires carry alot of current and since electrons (current) flows on the outside of the wire strands(thats why they use stranded wire more surface area as opposed to solid wire)when you use just a butt connector with the basic mechanics crimp tool that just squeezes two sides of the connector, you dont get good contact between all the strands and that limits the flow through the connector causing heat. Clear as mud!
Tuned
Joined: Dec 2006
Posts: 291
Likes: 4
From: houston,tx
from what farmnfly said i would go 2 sizes heavier on the wire and solder the connections. any wire will do thi if it has to carry more load than it's rated for and that presents a fire hazzard. Whitch seems to be a problem with some Fords of various years. 
Post Fiend
Joined: Nov 2003
Posts: 21,285
Likes: 16
From: Nutter Fort, WV
Sounds like you have a short at the glow plug relay.
The yellow and green wires from the relay going down to the controller under the relay have battery voltage on them when the relay is closed heating the glow plugs.
Either they are grounding out or the controller is toasted.
You could also have a short in the glow plug harness after the relay that is causing the problem.
The yellow and green wires from the relay going down to the controller under the relay have battery voltage on them when the relay is closed heating the glow plugs.
Either they are grounding out or the controller is toasted.
You could also have a short in the glow plug harness after the relay that is causing the problem.
Post Fiend
Joined: Nov 2003
Posts: 21,285
Likes: 16
From: Nutter Fort, WV
You can go to manual control, but you have to use a relay.
The glow plugs draw a little over 200 amps.
The glow plugs draw a little over 200 amps.
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Freshman User
Joined: Nov 2006
Posts: 35
Likes: 0
From: Chino Hills, Ca
Same thing happened to me recently, along with a few other strange electrical problems. Had to splice in new wires to get running again. I still haven't found a good shop manual or electrical diagram for my truck, just learning more as things break/burn-up.
Good luck,
WSM
Good luck,
WSM
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