1995 Chevy 454 intermitant hard to start

The relay I found was the heater blower. So continuing search under dog house I found another relay but it turned out to be the A/C relay. I checked out under the steering column, didn't find anything. Went back to the oil pressure switch and unplugged and cleaned. (forgot it was unplugged) Went try to start, Got chattering but no start, Now it gets weird, Plugged oil switch back in, From that point on key switch is dead. Now the only way to start is to use the MOM switch ! When running everything works normally. Turn the key switch off engine dies and nothing works again no head lights dash lights turn signals or Kwicki step. Hit MOM switch (don't have to hold ) everything live except key switch have to hold MOM then key switch works. I am up a tree, Checked every fuse I could find and all good. With engine started Chassis Battery 13.3 V Coach Battery charging at 14.4 V. Chassis Battery is brand new Les Schwab 84 mo. does not appear to be getting charge from alternator.
Regarding oil pressure switch, The engines starts shows oil pressure at gauge. No leaks around it. Hopefully someone here has some ideas where or what to check. Other wise I'm off to a mechanic tomorrow.

Did you check the fusible links to see if power was getting thru them?...

I wouldn't know a fusible link if it jumped up and bit me, Sorry, electrical is one of my many weak points. Seems strange that every thing works when using the MOM switch. Chassis battery seems to be out of the loop. Could be a fusible link to that circuit. Thanks.

if you had chattering it means you have a bad connection for your starting battery. remember you must have battery and ground for the starter to work , check both.

A fusible link is like an inline fuse built into the wire.. If you follow the main power leads from the battery to the firewall you may see something on the wire that is round and about an inch long and about the diameter of a pencil.. Take your test light and pierce the wire before and aft and see if power is going through.. If not new ones can be bought at the auto parts store...

Thanks all, The search goes on.

Click on this link for some info about fuel pump relay.

Be sure to scroll down the page for a rather good sketch.

Hope this helps.

I had a similar problem with my Georgie Boy 1996 454 TBI. Click here to read that thread.

Finally problem found and fixed. Pos Battery cable bolt at a connection, Bolt was cross Threaded at chevy or Winnebago 20 years ago creating a sometimes loose sometimes OK connection. Amazing it went so long with no problems until this past year.
I want to thank everyone for their responses, There is truly a wealth of information on this forum and people like you willing to share.

Thanks for the update!