69 charger starter solenoid question

[Edwards]

i have perhaps a stupid question here ..(probably as ive recently made the switch to building dodge cars). My background is in bodywork and paint and welding, so mechanic is not my strength.
What is the purpose of the starter solenoid on the chargers and mopars if the starter seems to have its own solenoid integrated? Is it more of a junction block for the coil/ main power feed,etc?
Im trying to do just a quick initial startup of my motor and bypass the cars wiring to see how the engine runs.

 

[Yatzee]

The starter solenoid is the interface between safety devices and the " engine start" process.
Sorta like "if/then" "if" the transmission is in Park or Neutral, "then" the engine can start without fear of movement. Imagine starting a car on high idle like when the choke is on and you accidently left in in gear. The other purpose is to take the load off the contacts in the ignition switch. Just look at the size of the wire going to the solenoid from the relay and it's source. The windings in the solenoid can easily draw 25 amps, way more than the ignition switch contacts can handle. This is the beauty of using load switching solenoids for any high amp circuit like electric fuel pumps, headlights, electric cooling fans etc.

 

[gkent]

I think you mean the thing on the firewall - that's not a solenoid, its a "relay". Yes, the solenoid is on the starter. The relay uses low amperage from the ignition switch to trigger the relay which sends higher amperage to energize the solenoid which then allows full battery amperage to turn the starter.

On a hard start those wires can get HOT - you don't want those inside the car.

 

[Edwards]

That makes a lot of sense, thanks for clearing that up. Ill probably be replacing that relay then since it looks pretty coroded and seems to be original.