2 issues, -no crank and -no radio...

My 71 LT1 was rebuilt this year after lying dormant since 1982. I paid Corvettes of Auburn(WA) to make it road worthy again and they did a great job! It was running fine until 3 weeks ago when an electrical gremlin decided to attack. (about 1000 miles since the re-awakening) The transistor amp, coil, TI Harness was replaced during rebuild. When the gremlin attacked I decided to go after it on my own... replaced the engine harness and both battery cables. Still not cranking, but at least now there is full voltage in all the right places. When I put the ignition switch to "start" position, the lights go dim, no clicking sounds at all other than when in "run" the CEC solenoid plunger fires as normal. By the way, this CEC plunger also fires when I turn the ignition to Accessory mode and I am suspicious if this is correct or not.

So, all is new on the engine side of the firewall, new battery too. Is the steering column, turn signal switch and harness my next plan of attack? I had the steering wheel pulled and tinkered with the key lock but nothing seemed unusual...what would you do next?

I have the center console out so I could get the center gauges, clock and radio all working...had the radio serviced, the shop replaced a transistor and cleaned it up so it checked out fine on the bench but doesn't make a sound in my car, guessing the are speakers shot?

 

If you're sure you have a good ground between the battery and the engine block (starter), I'm thinking it's time to pull the starter for inspection/rebuild. Check and make sure the 10ga purple wire on the solenoid inboard side gets 12v when the key is turned to start before you pull the starter

 

Thanks for the quick response Tim, I am reasonably sure that I have a good ground now that I changed out the harness and battery cables, but I'll double check the ground, as well as the voltage at the purple wire when key is turned to start. I have not done that yet step yet.

The starter was rebuilt about 300 miles ago so it would be odd to have gone bad, but I suppose anything is possible.

If voltage at the purple is less than 12 whenswitched to start, would you suspect the old ignition switch at that point?

 

Sounds like a very weak battery or a very bad engine ground. The OEM engine ground cables were made from aluminum with crimped-on aluminum eyes and over time corrosion builds up inside the eye to the point in which the cable is worthless at carrying current. If your aluminum cable is still on it rip it off and install a good copper cable with copper eyes.

 

When I went to fire up my 68 after motor install and harness replacement, I had the two wires on the starter solenoid reversed. I had them wired correctly according to the diagram I had, but the coil wires starting getting warm when I went to start it. Traced out that warm wire to the starter and swapped it out and was golden. Good luck.

 

Purple wire , at the inboard side terminal of the solenoid shows 0 voltage with and without the key in start position...now what?

Will i harm the transistor pulse amplifier by reversing the purple wire with the other solenoid side terminal?

 

Thank you everyone for helping me find the solution. It turned out to be a bad engine ground cable. I didn't realize that there is a cable from the frame to the engine block until I pulled the starter and saw it bolted there. Geez, what a simple fix had I only known.