I have four wires to connect to a new solenoid and cannot get the truck to start. I tried the battery cable on the bottom post (when mounted) ant the other three on the top post. I get no power to the cab or stater switch. Then I tried only the stater cable on the top post and the otheer three on the bottom post. The truck started but the starter will not shut off when the key is in the run position. What am I doing wrong?
You should have more then just the 2 posts correct? At least on of those should be coming from your ignition to pull the starter solenoid in, when returned to run from start, the solenoid then drops out.
Depending on what engine you have, which you did not state, you may have another wire coming to the solenoid for the electric fuel pump while in start.
The side your battery connects to, should also have the wires going to your power distribution system/alternator connected to it. The other large post should go to your starter, and starter only.
If the solenoid is closed even in "Run", that could be due to you having it connected wrong or a bad solenoid. I know you stated it is new, but new ones fail quit often if it's one you purchased at a local parts store.