Having issues with the glow plug system not working. The truck cranks fine, but the plugs don’t seem to engage. Any advice?
Does the truck start at all, or are you just worried about the clicking sound?
Haze said:
Does the truck start at all, or are you just worried about the clicking sound?
The engine cranks fine, but the glow plugs aren’t doing their job.
Did you check the fuse panel for corrosion? That can cause weird issues.
Rin said:
Did you check the fuse panel for corrosion? That can cause weird issues.
The fuse itself is fine. The tachometer runs off the same fuse, and it’s working perfectly when I turn the key.
@Stevie
I’ve had cases where the fuse tested good, but the fuse panel itself had corrosion, which blocked power. Worth a double-check.
Measure the voltage on the small wires at the relay. If it’s not a stable 12 volts, you’ll need to check upstream at the ignition switch. If it is, you might need a new relay.
Blake said:
Measure the voltage on the small wires at the relay. If it’s not a stable 12 volts, you’ll need to check upstream at the ignition switch. If it is, you might need a new relay.
I’ve already tried two new relays, including one from a new controller. I haven’t checked the small wires yet. Which ones should have power and when?
Where are you located? Sometimes the cold weather messes with electrical systems. Have you checked all the grounds?
Toby said:
Where are you located? Sometimes the cold weather messes with electrical systems. Have you checked all the grounds?
I’m in southern Oregon, just off the I-5. All the grounds are fresh and connect straight to the battery negatives.
What’s the voltage across the main terminals? If the relay clicks, there should be 12 volts going through it. Check the main lugs—one should have 12 volts all the time from the battery, and when the relay clicks, the other should also show 12 volts. Then check for voltage at the stud leading to the glow plug wires.
I had a similar issue, and it turned out my fusible links feeding the controller were partially fried. They looked fine outside, but only one strand of wire was intact. Might be worth checking those links. Also, low battery voltage can cause weird short-cycling issues, but it doesn’t sound like that’s your problem.
@Ren
Batteries are good and grounds are fresh. Would a partially fried fusible link still show good continuity? I’m seeing 0 ohms on both wires. Also, what’s that plug on the back of the controller? Is it fusible too?
@Stevie
Even with proper voltage, the single strand might not deliver enough amperage for the plugs to work. As for the plug, I think it connects to the Wait to Start light on the dash. Are the wires going into it blue?
@Ren
Makes sense. I’ll look into replacing those links. Do you know the amperage rating for them?
Stevie said:
@Ren
Makes sense. I’ll look into replacing those links. Do you know the amperage rating for them?
I’m not sure about the amperage. I might have a wiring diagram saved. If you need it, I can send it through the forum’s messenger.
This guide might help: Crank No Start 7.3 Power Stroke.
Peyton said:
This guide might help: Crank No Start 7.3 Power Stroke.
This is for the Power Stroke. Mine’s an IDI.