Need help please

Stock antennas suck anyways. Put in an aftermarket like a Wilson or firestik and call it a day. Run some good coax too as others have said.

What kind of truck is it?

 

No wonder why the radio doesn't work........ that thing looks beat

 

Your radio.......... years ago had to drive those junkie old day cabs too be lucky if the defroster worked in them

 

I would leave it alone because it works for am/fm and put in a separate CB antenna.

See the thing is setup is with a little box that combines the two radios together on one antenna, in amateur radio a lot of us use them with separate radios (like 2M and 220/440 radios) but with marginal performance so I wouldn't mess with it if it works on one radio, just add the second antenna to the other side of the truck, run good coax to it and be done with it.

I am wondering about the CB power, is there a place for CB power like binding posts on the dash or in the compartment above you or even if it has a compartment? I am guessing that maybe it is there if there is a place for a CB. I drove an international a while back and the radio was on the dash and the CB was above on the roof part.

 

On my 9900, the cb mounts on the drivers side, over head compartment. There should be a set of binding post there. The factory coax cable should be there as well but, someone may have removed it because the factory setup sucks!
There should be antenna mounts at the top of each mirror, towards the top of the plastic case, welded to the pipe. Look to see if there is an antenna stud on either mount, and if there is coax atatched there. If so, you can trace it inside the truck. If it is factory, it will run behind the dash, to the multiplexer box, then up the drivers side of the cab, to the overhead. This is assuming the 9400's and 9900's are the same.
You would be far better off to run your own coax and antenna, as others have said. This way, you know what is there, how its installed, and your radio will perform much better also. Jmo

 

Sweet