Project car: assuming bad starter relay. Confirm?

-1969 Barracuda
-318 originally
-Factory 4 speed (looks like no clutch safety post on starter relay)
-Recently put power to the system for the first time. Power going correctly through the bulkhead “J” connection... And back out through yellow wire to relay.
-I’ve scoured the entire starter relay (and connections) and rebolted it to the fender.

Yes, I have many versions of the electrical diagrams.

I’m getting excellent voltage at the yellow (now grey, along with ALL wires in my engine bay... a previous owner painted entire bay and wires) wire when turning ignition switch in “Start” position. Correctly no volts when NOT in “start.”

No voltage EVER gets to the “Sol” post on the starter relay. I do get voltage at the “Sol” post when I connect a jumper wire from yellow Ignition post to “sol” and only when I twist key to “start.” Relay never makes a sound (clicking?).

Hmm. Jumper the sol housing to the negative post to verify ground maybe. Jumper the positive post to the start post on the sol also.

JAndrea said:

I do get voltage at the “Sol” post when I connect a jumper wire from yellow Ignition post to “sol” and only when I twist key to “start.”

Click to expand...

That may not be large enough wires to carrythe current needed by the starter solenoid.

Jump it this way - which more directly feeding the starter solenoid from the battery.
That's what the erlay should be doing internally.


Of course make sure the car is out of gear and hand brake on.
A screwdriver with insulated handle will work.

If the solenoid doesn't engage or at least click, check the starter and rechack the battery and battery cable connection.
A charged battery with no load should be 12.5 to 12.8 V
During starting it may drop. if it drops below 9 or 10 its on the weak side.

JAndrea said:

-1969 Barracuda
-318 originally
-Factory 4 speed (looks like no clutch safety post on starter relay)
-Recently put power to the system for the first time. Power going correctly through the bulkhead “J” connection... And back out through yellow wire to relay.
-I’ve scoured the entire starter relay (and connections) and rebolted it to the fender.

Yes, I have many versions of the electrical diagrams.

I’m getting excellent voltage at the yellow (now grey, along with ALL wires in my engine bay... a previous owner painted entire bay and wires) wire when turning ignition switch in “Start” position. Correctly no volts when NOT in “start.”

No voltage EVER gets to the “Sol” post on the starter relay. I do get voltage at the “Sol” post when I connect a jumper wire from yellow Ignition post to “sol” and only when I twist key to “start.” Relay never makes a sound (clicking?).

View attachment 1715494116

Click to expand...

If you jumper from the big hot terminal to the "no volts ever" terminal and the starter works then it's not the relay or solenoid. The big terminal is always hot. If not, there's at least one of your problems. Voltage is supplied to the "no volts ever" terminal when the key is turned to the start position. The bottom wire is the neutral safety switch.

Demonic... you totally got me on track. I found that I couldn’t get a ground from the relay housing... or anywhere on the fender... which made me think the fender isn’t grounded? Which led me to remembering that I had a ground connection dangling from the firewall in the engine compartment... then I remembered a line from an electrical post I read a few days ago.. “remember to ground the firewall strap to the motor” once I got that connected, the relay worked perfectly on key “start” position... lit up my test light, and made the faint “clicking” sound.

Thanks for the responses guys... I know electrical problems are super difficult to troubleshoot from afar, and often with missing bits of information!

Demonic said:

Hmm. Jumper the sol housing to the negative post to verify ground maybe. Jumper the positive post to the start post on the sol also.

Click to expand...

Thanks, my friend!

Mattax said:

That may not be large enough wires to carrythe current needed by the starter solenoid.

Jump it this way - which more directly feeding the starter solenoid from the battery.
That's what the erlay should be doing internally.
View attachment 1715494190

Of course make sure the car is out of gear and hand brake on.
A screwdriver with insulated handle will work.

If the solenoid doesn't engage or at least click, check the starter and rechack the battery and battery cable connection.
A charged battery with no load should be 12.5 to 12.8 V
During starting it may drop. if it drops below 9 or 10 its on the weak side.

Click to expand...

Thanks! I’m at 12.7 volts, and really just verifying the basics right now. No alternator, radiator, drive shaft, etc... Do have new RobbMC starter. electronic regulator, Ballast resistor, and ECU, however.

Whenever I look at my starter relay in the future I will always remember the "no volts ever" post.

Put power and ground to the relay coil then check the relay switch with an Ohmmeter to see if it closes. It's a simple switch.

HOW to do this

1. Jumper (using screwdriver, etc) between the two large posts. That is, the big stud and the big square solenoid terminal..... The starter should operate so be careful you have it in park/ neutral. This proves the starter, the battery cables, and the big wire down to the solenoid are all OK

2...Remove the push on flag terminal (wire). Jumper from the big stud to that flag terminal. The relay should operate the starter

3...If not, maybe the relay is NOT GROUNDING. Loosen the mounting bolt and retighten. Then clip a jumper to a good ground on the engine, and jumper into that solder spot on the top of the relay that jumpers over to the case. Now, use a screwdriver or jumper to again jump from the big stud to the flag terminal. If it does not crank, replace the relay If it does crank, either the solder jumper to the case is broken, or the case is still not grounding to the body

I tend to get "too deep" quickly. I wast no time grapping some "alligator clip" jumper leads, my meter (Fluke) and a test lamp I highly recommend good used Fluke meters over much of the HF freight stuff you see. Seen too many of them fail and become grossly inaccurate. I've bought used Flukes for as low as 25 bucks up to about 50, a bit more for a "juicy" one.