Help needed please no power no start

[Stangit62]

Hi all, sorry for this long first post but, I am in need of getting my recently purchased 1979 Coachman class A 454 with 79,000 miles started. I am stuck in Texas at daughters house with a no start condition. Here's the low down. I drove it all the way from Illinois to Texas. It Started and ran good all the way here. Soon as I parked it and let it sit for a few days using shore power, I tried to start it to go empty the tanks and all I got was a click. Tried tapping on the starter but upon closer look at the starter, the solenoid with plastic cover was fried. I recently purchased this old heap (first RV) to have a project to work on through the winter down here and the previous owner included some new parts, one being a starter. So I replaced it and repaired the terminal ends on the little wires too. I also noticed that the main ground hub on passenger side, where ALL battery grounds are attached, (coach and chassis) was rusted. I tried to take it apart to wire brush the bolt and cable ends but it broke. I drilled a new hole and installed a new 3/8" bolt and re attached all the grounds and it then started and I ran it for 20 minutes, and took the opportunity to run the generator too. I thought all was well so I shut it off. 30 minutes later I tried starting it again and all I got was the same click again, so I re-inspected all my work and verified it was all good. I had my grandson try turning the key so I could better hear where this click noise was emanating from and it was coming from a rusty tin can with 4 terminals and wires near the alternator underneath the dog house. I read a little bit on this device and I assumed it was an ISOLATOR. I also saw one underneath the hood near the engine and (single) coach battery. They were both rusty and old looking so I ordered 2 ISOLATORS from Amazon and installed them being careful to re-attach all the wires the same way while also replacing the wire terminal connectors too.
I then tried starting it and got nothing but a click AGAIN! To make matters worse my daughter and son in law were given a warning by the city of Mesquite to move this old heap off of the grass and onto the paved driveway or else it will be towed. I have until the 19th to move this thing...
I have come to learn about the Chevy hot start problems and the Fix using a 2nd starter solenoid some even using a Ford unit. So I may have replaced the 2nd start solenoid on top of engine with an Isolator instead. I tried to bypass the thing and attach the wires together that were at one time spliced to accommodate this 2nd solenoid. BUT I forgot to disconnect the battery and sparks ensued smh..so I think I may have shorted something out that is currently preventing any power to the engine starting circuit.

What I have done and checked so far..
I checked and re-checked all the grounds I could trace pertaining to chassis starting circuit including big strap on left side of engine.
The chassis battery has been charged 2 times and currently at 12.67.
No power at the replaced Isolator can thing. Did I buy the wrong part?
I have power from battery to the big starter terminal BUT none at the small terminal that goes to ignition switch(?) with key on or off.
Disconnected ignition switch plug, no power at all key on or off.
I replaced all the fuses with new ones. No power at any of them.

I am going to remove the new starter and run cables to it to test it to see if the starter solenoid may have shorted and fried not allowing power to ignition switch?.
I want to replace the fusible links at the starter but need to know where others may be..was told that there may be one at the alternator and ignition switch?

Don't know what else to check off the top of my head..Any help from anyone regarding this is greatly appreciated. I'm stuck here with my dog, my funds are being depleted and I don't want the vultures from code enforcement taking my home to a junkyard..Any Chevy techs with experience on these old coachs please help!
I can post pics of this monstrosity if the site allows me to..

[mobilefleet]

almost certainly a bad cable, prob ground. Replace pos and neg battery cables, they corrode from inside out and cannot be visible. The ground cable from the battery likely goes either to a starter bolt or to the frame somewhere.

[Matt_Colie]

Stang,

First - you seem to be an effective diagnostician, but you seem to be missing two things....
Get/make a test light. With clips so you can let go.
Get a helper to twist the key. (If you can, it makes things much easier.)

Do a first test with it at the power terminal of the starter.

Hit Crank. Does the light stay on or go out.
If it stays on, the solenoid/started is/are bad. Go get a rebuild with a lifetime warranty and keep the receipt.
=>If you want to go farther, do it again at the post into the starter. If the light stays out, you may only need a solenoid.

If the light goes out, something upstream is bad. Keep moving up the way until the light stays on then you know that the prior joint was junk.

The starter on that engine is the famous Delco 10MT. They are known for being too robust. They just keep cranking when they should have quit, so when they do quit - Oh Mama do they quit. Usually happens at about 100K for RVs.

Good Luck Guy

Matt

[enblethen]

Look at old starter for the jumper!

[enblethen]

The tin can is a starter relay used on some Chev chassis. The two small terminals are the control and the two large terminals supply power to the starter.
You could try using a heavy piece of wire and bypass the relay by connecting the two large terminals together. It will arc! The starter should kick right in and turn over the engine.
On this type of setup, there is a jumper between the large battery post on the starter and the small terminal marked "st".
Doesn't like my edit. Verify that there is jumper on starter!