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Schematic Wiring Diagram? 2007 J08E - 7.7l UD No Crank No Start same as some hino

MNROADSIDE

Rookie Expediter
Owner/Operator
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I need a wiring diagram or schematic for My 2007 UD 1800HD / J08E 7.7l diesel
had some really cold days this winter and the last time it got -20 outside I had to jump the battery. Then the next day it was no crank no start - cleaned cables and batteries. Then 20-30 minutes after it didn’t have any dash light and no crank it started right up. Then after driving it all day without any issues I parked and next morning no crank no start again.

I replaced the battery cables because they were going bad anyways, cleaned everything replaced a few small terminals and then nothing, no dash lights no crank.

Now I checked the engine grounds, the starter is also good - connections are clean now. I have tested and checked every fuse I can find in the dash and near the battery. I have accessories on like the radio, fan, headlights, etc.. those all work fine.

ignition —fuse — relay — relay —> after these where is the next places to check.
I’m also wondering if there’s any schematics - wiring diagrams. I have a signal to both relays and fuses from my ignition “ON” From here where should I check? I am not a mechanic or electrician but I know I should be able to check others sensors located on the engine for reference voltage and that should tell me if the computer has took a :censoredsign:. If anyone can just give me the amps that should be present with the key to running position at the mass air flow sensor, and maybe some other location with the minimum acceptable amps. I just don’t know enough to know the amps / or if they are similar in all vehicles? Is there a way to check the ecu at the computer itself, would a schematic show reference voltage, ohms also?
 

greasytshirt

Moderator
Staff member
Mechanic
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I don't think Hino wiring diagrams are going to help you.
The ECU is absolutely the last thing to consider. You have a million other things to verify first.
 

MNROADSIDE

Rookie Expediter
Owner/Operator
Offline
I don't think Hino wiring diagrams are going to help you.
The ECU is absolutely the last thing to consider. You have a million other things to verify first.
What’s the next thing to consider, I can’t communicate with my Computer. I also seem to have power going to the ecu. Where would u check next after looking at the grounds, fuses relays and knowing u have no dash lights coming on etc
 

MNROADSIDE

Rookie Expediter
Owner/Operator
Offline
I don't think Hino wiring diagrams are going to help you.
The ECU is absolutely the last thing to consider. You have a million other things to verify first.
And the 2005+ UD had Hino engines installed in them, mine is a J08E, even my diagnostic tool has to go to Hino to communicate. I’m just thinking that a Hino with a j08E will at least give me an idea of the wiring
 
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