Technical Painless Ignition Switch / Painless Harness

Yes at ignition switch, no idea why the drop but you'd think that acc. spot in the fuse box wouldn't have 12 volts if it was anywhere else other than something in the switch.

 

Just to be sure. I understand @ the IGN. switch its self. My concern is with the Bat. terminal only. Is it reading 9.3 when you twist the key to start position. I’m trying to understand is it a power wire in issue or a switch issue? which would be a power out issue.

 

Ignition switch battery post shows the same voltage as tested directly on the battery, when you flip switch to run position it drops from 12.65 to 12.37-38 on both battery post on Ignition Switch and coil wire out of fuse box, then both of them drop to 9.5 while cranking the engine.

 

If I'm reading what you're saying right, voltage at the battery terminal is dropping to 9.5 volts when cranking. If that's the case, try this: disconnect the start wire at the switch and try it again in the start position, checking for battery voltage on the ignition and battery terminals. If it drops more than a few hundredths, it's very likely the switch. If it doesn't drop (or very little), the problem is in the solenoid or the wire going to it. Reconnect the wire at the switch and disconnect it at the solenoid. Test again as above. If the problem goes away, it's a bad solenoid. If not, it's the wire. Maybe a low-grade short or bad crimp...

 

That wording tells me/us there is a drop in the Red primary wire feeding to the IGN. switch. Would you agree? After all, that’s what’s feeding the switch.

 

Wouldn’t that much pull down from the solenoid cause a no start (starter won’t turn) issue?

 

All battery cables and soldered terminals are from Battery Cable USA which are super quality made in USA products, multiple grounds.
I run the same setup on another car, same cables, same ignition switch, msd 6al, same ground positions, only difference is used a Rebel harness on that one.
My other car I wired from scratch just using a 12 circuit blank fuse box, I don't know everything but also not new to wiring, normally do plenty of research before posting an issue on an online forum.

 

As long as the solenoid pulls in it'll crank. It has been cranking, so the low voltage isn't preventing that.

 

For a little back information when I first wired this truck back in the 90's with a Painless universal 21 circuit I had the same issue of not starting. I ended up just using a jumper wire out of the fuse box to bypass the coil wire after 3 days of going over every wire and connection.
I have the same ignition system in it, same but different starter, of course different battery and I'm pretty sure I put a different ignition switch in it.
It sit in the garage for 23 yrs just being started a few times a year until I started driving it a few yrs ago, last year I fried the harness do to a stupid mistake and the design of that harness, hence the new harness going in.

Edit : definitely a different ignition switch later on because I had a GM column with column ignition switch when I first built the truck, so the initial no start issue was with that column.

 

New switch came in and in it went, works like a charm, so something was screwy with my old switch to make it drop voltage like I thought.
Once you get past the diagnosing problem it was an easy fix. Lol

 

Was the starter cranking when you got the 9.5 volts? If so, what is the battery voltage during cranking? If not, and all wires were connected where they need to be, it sounds like there is a ballast resistor in the circuit. Also, what is the voltage at that accessory terminal during cranking?

 

Normally there should be no voltage to Accessory when cranking. Just as in the daily go to work rig, when you turn the key on the radio comes on but when you go to crank it the radio goes out until you let off the key.

 

The new ignition switch solved the issue but the 9.5 was with the engine cranking, no idea what the voltage at the battery was, I couldn't test that and turn the key at the same time.

 

The reason I ask is that is the threshold voltage indicating a battery or starter problem. In your case it may be normal, but anything lower would be a problem.