C Line wiring diagram

Has anybody got an operators manual or workshop manual for the C series International.

I have a spare wire coming out of the engine firewall plug and I can't work out what it is supposed to go to.
I have 7 wires coming out of the plug.

They are:
Oil pressure sender
Water temp sender
Coil positive
Alternator (to voltage meter)
Starter solenoid
Power supply to cab (from starter motor/battery/alternator)

There was one extra wire that was tied up around the choke cable when I pulled the motor out. It runs into 3 wires on the cabin side of the plug and they all go into the main loom but it has been difficult tracing them back without pulling the dash apart and I don't really want to open up a hornets nest if I don't have to.
I've tried earthing it thru a globe, I've tried powering it. I've checked to see if it becomes active when anything swithces on but no luck. Was thinking it could be a reversing light but there's no switch on the gearbox to hook it up to either.

My D series operators manual shows a low vacuum sensor but the little truck doesn't run vacuum and I doubt they would have had a loose wire like that from the factory if it wasn't needed.

There's a manual on Ebay at the moment that I am bidding on but even if I win it I won't get it home till the end of next week and hoping to have it in for rego before then.

Any help much appreciated.

brake fail light ? washer wire ? under hood courtesy light lol ... just think what other wires would be in the engine compartment

Cobba - Yes, I have the manuals for AB, C and D series. You do know that all the wiring is numbered, don't you? .. with the number imprinted at regular intervals along the wire .. except for short wires, that have the numbers imprinted at the ends.

It would help if you can give me the precise truck model and the engine size. There are numerous wiring diagrams according to the truck model, and the engine fitted.

My main computer has fritzed and I can't use my scanner at present. However, the manual is probably too thick to scan.
I'll try taking a photo of the wiring page and wiring ID chart tomorrow, and uploading it, and see how it pans out.

Cheers - Ron.

brake fail light ? washer wire ? under hood courtesy light lol ... just think what other wires would be in the engine compartment

Brake fail, wiper/washer wires are all there thru another loom. If I don't find a use for it I might turn it into a courtesy light. Novel idea for a 70s truck.



Ron. It is for a C1300 with a 6-281 petrol engine. The same one I have just been rebuilding the engine for. Sorry, I should have put that in but I have only got 2 trucks and they are both International C1300s running the 281 engine.

I am aware that C line had numbered wiring but this particular wire doesn't have anything on it. One of the 3 wires it connects up to inside the cabin has the number "12" on it if that helps. I cant see anything on the other 2 wires before they get covered with tape

Not really wanting a copy of the diagram. If I can't read it then I am no better off and will have to get you to translate it anyway. I am just after the name of the item that it should be hooked up to.
If you could look at the diagram and find the engine plug there will be wires that run to 2 senders (oil, temp), 2 wires to the starter (solenoid and cabin power), 1 to the coil and 1 to the alternator.
I am wanting to know where or what any other wires from that group/plug might go.

O.K. I'm having a big problem getting the wiring diagram on line, anyway, because the print is so fine. I actually need a magnifying glass to read the details on the page.
I know my eyesight isn't what it used to be .. but that print is FINE, I tell ya.

Number 12 is the coil low-tension wire, from the ignition switch, to the LT connection on the coil, and thence to the distributor. This is essentially a wire that is powered when the ignition is on .. so I'd suggest the stray wire is for an accessory that only needed power when the ignition was on.

The wiring harness firewall connector has up to 8 wires in the plug. Reading from top to bottom on the diagram (could be different the way you're looking at it ) .. the numbers and uses are as follows ..

129 ..... voltage regulator D+ terminal to "I" on ignition switch ..
14 ....... "S" terminal on the starter solenoid (the small terminal) to "S" terminal on the ignition switch ..
12 ....... LT wire from LT terminal on coil to "I" terminal on ignition switch ..
30 ....... fuel gauge sender unit to fuel gauge ..
33 ....... water temperature sender to water temperature gauge ..
36 ....... oil pressure sender to oil pressure gauge ..
15 ....... power wire from + battery (starter) cable to "B" terminal on light switch ..
85 ....... low vacuum switch to low vacuum indicator light ..

I trust this helps you out ..

Cheers, Ron ..

Thanks Ronny.
Reading thru the list the only one that I haven't checked for connection is the fuel guage wire and concidering the guage always reads full then there's a fair chance that is what it is. Will crawl under when I get a chance and have a better look.

Thanks for your help. Will let you know how I go with it when I sort it out.

Cheers. Cobba.

I pulled the dash out yesterday and traced that wire back. I think you were right with your extra coil wire Ron. The other end is sitting loose at the ignition switch.
I haven't finished tracing all the wires yet. It has 3 wires each end inside the cab but one end looks to be numbered 2, 3, and 4 while the only number I can find on the other end appears to be 12. I have to get in and have a serious look to see that they don't spit and go different locations within the loom.

If it's not coil then it's something to do with a vacuum system as I found the remains of an airline inside the right chassis rail when checking out the fuel tank sender wire.


I'm not too bad at the wiring side of things but it's never a good feeling when smoke starts coming out from under the dash so I want to get it sorted out right the first time.

Just remember Cobba, every piece of wire has smoke in it. Once you let it out the wires stuffed.