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M1028 help
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Keith_J
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What did you do to it? Which wires did you move or connect?
The firewall resistor bank is a voltage divider network to drop battery voltage to around 12 volts when the glow plug solenoid is engaged. In doing so, it heats up, approximately the same heat energy is dissipated in the resistors as in the glow plugs, it will get hot. If the prior owner pimped the engine bay with Armor All, WD40 or any other product to hide dust, this substance will cause smoke.
You will need to download the technical manuals and make sure the wiring follows the diagrams.
The firewall resistor bank is a voltage divider network to drop battery voltage to around 12 volts when the glow plug solenoid is engaged. In doing so, it heats up, approximately the same heat energy is dissipated in the resistors as in the glow plugs, it will get hot. If the prior owner pimped the engine bay with Armor All, WD40 or any other product to hide dust, this substance will cause smoke.
You will need to download the technical manuals and make sure the wiring follows the diagrams.
Nothing was done to it(the glow plug system), nothing has changed, the only problem I had was a power steering pump came loose from the tensioner bracket. I disconnected the alternator (the week before) to get to the power steering pump, tightened the two bolts back into the pump, (never removed any of the wiring to the alternator, tightened the pump belt back up, reinstalled the alternator, tightened that belt back up, started the truck(using the glow plug system) and drove the truck 3 different times. Now this problem out of the blue...
Keith_J
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Probably the solenoid welded itself shut. Could be the control card if the output transistor failed short.
The solenoid main lugs should have 24 volts measured at the top or resistor side with key on, engine off. The lug with three orange wires (2 large, one small) should be 0 volts except with glow plug system on.
There are two smaller lugs, one is switched 12 volts, the other goes to the control card since NPN transistors are ground sources when triggered. I forget those colors..
The solenoid main lugs should have 24 volts measured at the top or resistor side with key on, engine off. The lug with three orange wires (2 large, one small) should be 0 volts except with glow plug system on.
There are two smaller lugs, one is switched 12 volts, the other goes to the control card since NPN transistors are ground sources when triggered. I forget those colors..
Solenoid tests open on ohms with key off...
Was possible suspecting it was the card and I have a spare, but didn't just want to try it without some definitive troublesooting, I think I have a resistor too, but not sure at this point where it is at...
Voltages correct b4 and after,with both key off and on(with wire hooked up to top of solenoid) have to have wire off of solenoid to leave key on and/or truck running,or I will start smoking the wiring and resistor, not sure last 2 x's I heard the solenoid open(after timing out) for the glowplug heating cycle, was moving fast to try and stop the issue/problem b4 it caused alot of damage, think resistor is OK, but don't know the ohms value it should read also...
?..
I'm starting to suspect the card
I'm starting to suspect the controller card...
Keith_J
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The controller card will show heat damage to the output transistor if bad. Pull it and examine. Improved version can be bought at Hillbilly Wizard, pricey but well designed.
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Saint, Please write your State in the location block, IAW the forum rules.
Ok
It says it has to be added to my profile, IDK how to get to my profile?
Thanx Keith
I'll check it out today...
I think I got it now, I had the city listed as the location, changed it to the State
Yea
It's cooked,know where I can get another one that dosent cost a arm and a leg...
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Keith_J
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That is the output diode, not transistor. The transistor is the black block with three wires and the screw on the heat sink. It could be fixed but anyone with the skills would charge $180 plus postage.
This damage is usually caused by incorrect connection, easy to do as half of the terminals on the relay have power when running, toss a wrench on them and it can let the smoke out.
I still recommend the upgraded module as it has diagnostic indicator lights. You have an earlier type with protection diode for the transistor, that is what burned. It also toasted a resistor.
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Keith_J
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Please view this video. Insulate all 4 terminals on the solenoid once fixed. And always disconnect both batteries before any electrical work.
Keith_J
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The diode is IN4004 or similar. Resistor 5100 ohm, 3% tolerance.
I would desolder the diode carefully to test if it is the failure. Ohmmeter should be open one way, .3 to .8 volts on diode test the other way. If short both ways, it was the fault. It toasted the 5100 ohm resistor too. Repair probably includes copper trace on the other side as through hole leads conduct enough heat to debond.
I would also test the transistor.
Edit: Pulled the working control card from my CUCV to trace and test. The component which over heated is the solenoid lead protection diode. 1N4001 with the cathode band towards the edge connection. The resistor next to it measures out at 5.12 k ohms.
I would desolder the diode carefully to test if it is the failure. Ohmmeter should be open one way, .3 to .8 volts on diode test the other way. If short both ways, it was the fault. It toasted the 5100 ohm resistor too. Repair probably includes copper trace on the other side as through hole leads conduct enough heat to debond.
I would also test the transistor.
Edit: Pulled the working control card from my CUCV to trace and test. The component which over heated is the solenoid lead protection diode. 1N4001 with the cathode band towards the edge connection. The resistor next to it measures out at 5.12 k ohms.
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Keith_J
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Here is the behind the TM technical info:
It has correct placement for the thin orange wire on the large output lug of the solenoid. Identified in TM as .5 mm ORN-503B. Wire identification is by diameter in mm, then color, hyphen circuit number ID and any branch is a letter suffix.
The TM is written on an 8th grade level (for 1980s levels), this document is high school shop level.
It has correct placement for the thin orange wire on the large output lug of the solenoid. Identified in TM as .5 mm ORN-503B. Wire identification is by diameter in mm, then color, hyphen circuit number ID and any branch is a letter suffix.
The TM is written on an 8th grade level (for 1980s levels), this document is high school shop level.
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