I think there are some in the I&T manual for that model and of course they are in the factory ones. Since you're specifying the cab, I'm gonna guess you've lost power to the blower and other functions up top perhaps If this is so, its a ***** to access but there is a plug in the harness right above where your head is when you climb thru the door and often that plug gets hot , melts and has bad connection afterwards. Most times it is only the power wire that is effected in my experience, I have always just spliced a heavy gauge wire around the plug on that one wire and left the rest intact. Not saying this is your issue, just a common one I have dealt with

 

If you have no power up there it might be the solenoid/breaker block under the starter also. The genuine Case service manual is by far the best for those. You might be able to get a used one from a dealer or such. We still have three 2290s and a 2390 to go before I can give ours away .

 

ok thanks,and yes i have no power in the cab,the guy said he took it somewhere and had some rear end work done on it and removed the cab to do it,and when they set the cab back on nothing worked.I did have power to all the fuses,and it made me think i had a ground problem,and i went to that big connector under the cab and wiggled it around and lost all my power,it wont even start with the key now.i was able to bypass the blower relay below the starter and get it working but nothing else does,lol.and of course the wiring on this thing has been hacked and spliced all over the place.

 

anyone know where I can find a wire diagram for a IH combine 1688