after changing parts still no start just click

I checked the wires I get continually i know it's not a voltage drop. But I just noticed something else. I can start it by jumping the solenoid by the way I even tested the old solenoid it works. What I noticed was if I remove the negitive battery wire and it turns off. So now I think I need to change the alternator. It could also just be bad wires. I wouldn't imagine that having a bad alternator would cause it not to start. I just really started out changing the solenoid because I was just getting a click from it. I'm confused.

Thanks for the reply I'll grind down where the solenoid is mounted to is is that does the trick

Ok where to start. Where the solenoid goes I took it down to bare metal this time I reinstalled the old solenoid. Put everything back tried to start it nothing. So while I was turning the key I heard clicking ,but it sounded like it was coming from underneath the RV . So I opened the passenger side door so when I tried to turn it on with the key again I can heard better where the clicking was coming from because it didn't sound like it was coming from the engine compartment. So walked around tried the key a few times nothing but then o tried it again and it started. Bizzare . So I turned it off tried again ,again it started. So now wanted to see if the alternator was not working because I removed the battery cable and he other day and it shut off. Tomorrow I will check for any other fusible like before purchasing a new alternator. I did see a long wire going up to the main solenoid from a continuous solenoid And auto reset circuit breaker .I'm thinking that is where the clicking was coming from . More troubleshooting tomorrow but for now at least it started. Thanks for all the help

well i guess the problem was that it wasn't getting good ground because it starts now. i wish i had checked this site for help before buying 2 solenoids . the first solenoid i tightened the nut too much and broke it. i winded up using the old solenoid that was originally on the fender . I appreciate all the help THANK YOU very much. I do still have to replace the alternator because the RV turns off when I remove one of the battery cables . oh and I bought a continuous duty solenoid and auto reset breaker to replace that rusty one of that pic I posted previously .

PS. after I remove the alternator I will test it or get it tested before going out to purchase a new one.

thanks will do and i will probably also change the wires they look old too. .