I have an 86 International S1900 with a DT466 and an automatic. I put 2 brand new batteries and the truck acts like it has no power. At first it lit the oil pressure light but now there is nothing. Can someone help me with a wiring diagram or at least some good places to start checking?
Check the bulkhead connector for burnt terminals. Very common. Also check your grounds from the battery to the frame, to the cab. 10ga wire off the starters ground post may have broke or been omitted.
I will check the grounds for sure. The brides ground to the frame is good as I got 12.6 volts from positive to the eyelet. Where is the bulkhead connector?
Above the steering column, on the firewall, you'll see a black plastic cover. Multiple harness bundles leading into it. Remove the cover, you'll see all the wires terminated into 2 interlocking plastic housings. Should be a central screw, remove that to pull housings forward. Check all the terminals for scorch marks, corrosion or distortions. Hopefully, a crappy ground somewhere.
Here is a link to the wiring manual for the 1988 1000 series: 88 1000.pdf drive.google.com It should be very close to your 86. Is there a big solenoid mounted in the centre top of the firewall?
There is a solenoid mounted on the firewall yes. I messed with the harness and now I have headlights and the horn relay click when I hit the button. Voltmeter reads lowest position but it twitches when I hit the key. Still no crank.
If I'm not mistaken that big solenoid is powered on by the key and supplies "Ignition" power to all the circuits. If that solenoid is failing it can cause problems.
I have 12 volts on the battery side and the other is ground it looks like. I’ve got nothing on the small wire. Also verified proper ground on the starter to the frame.
Can you post a pic of the solenoid? The 1900 may not use the power solenoid.
Here is a pic of the solenoid.
I'm not sure what that solenoid is for. The one I was referring to is located at the centre of the firewall a few inches below where the hood rests.
Right below the solenoid is the bulkhead connector funwithfuel mentioned. Did you remove/inspect that connector for greenies? Maybe try cleaning the terminals on that solenoid, actually remove and sand the ends till they're shiny. If that doesn't work, make sure the truck is in neutral with the brakes set and try jumping the large top and bottom terminals (the ones with the rubber boots). If it kicks starter when jumped solenoid is bad. Looks to be very common solenoid, probably available at parts store or tractor supply. Furthermore where is the rest of that red wire that is broken off the rusty stud to the left of the solenoid? Just may be of some importance. The more ya look the more crap ya see, how about the black wire that's ziptied to the main harness and runs down in front of bulkhead plug, looks like something was chewing on that thing especially up by the ziptie, chances are if you pull on that wire it's got greenies under the insulation and comes apart in your fingers. Zoiks, when's the last time this thing actually ran?
The bulkhead power connection mentioned several times above is/can be a issue, the grounding lug on firewall right below looks to be a issue too. The solenoid is factory starter. Has/does the windshield leak around gasket like most with age, because those normally drip right on the fuse panel.
Those things leaked when they were new.
Edit to previous post; you should have power to the little wire/stud on the solenoid when you turn and hold key to start position. If no juice with key in start position, solenoid may not be the issue.
It's why I brought it up---another reason not to own a IH.