3 post selinoid

[awynne56]

I have a 350 sbc with battery under passenger seat. The battery is connected to everthing via a 3post selioind.. first it seems like there are alot of wires over on the driver side post of selinoid. Second can i use the left side of the selinoid to jumper a positive cable to a high out put aux fuse box ie the safety hub 150.(to hook after market heater and fog lights) or do I have to directly connect to positive side of the battery? Also am I correct in assuming that the relay in the second pitures is for my electical radiator fan?
Thanks for any and all help. Andy

 

[Downey]

I'm certainly not the last word on wiring, but I will tell you what I see in your top photo:
Passengers side post has 12 volts coming to it, plus many wires going to things that would get a constant 12 volts, even with the key off, engine not running. Drivers side post appears to be wiring things that would only receive 12 volts when the key is on and the engine running. The center post is probably wired to the starter, giving the starter power only when cranking, with key in the start position. Does this make sense???

 

[awynne56]

From what I thought it was pass side was wired for on all the time as well as alternator that goes to oem fuse box the center post I thought was switch for ignition when charged it connected the electromagnets in the selinoid which then sent current through to the other post and the starter.. ther starter would then crank start engine and the current to the starter would stop and the electro magnets seperatored... so I guess I'm confused.. if electric was the way you said wouldn't the starter always be in gauged? I again have no idea, Downey.. you could be 100% right. Like all rigs the PO does stuff and it doesn't come with directions of what they did.. I might start keeping a log. Downey thanks again for your response... I'm am now throughly confused. Lol.

 

[bkdraft]

One side is hot all the time, other side only hot when voltage applied to center wire. Since it has more than one wire hooked to post, I am assuming this is NOT the starter solonoid. Appears to me to be used to cut off voltage to certain things via manual switch or ignition switch. Need to trace out wires and see where each on goes.

 

[Aliveiride]

I'm certainly not the last word on wiring, but I will tell you what I see in your top photo:
Passengers side post has 12 volts coming to it, plus many wires going to things that would get a constant 12 volts, even with the key off, engine not running. Drivers side post appears to be wiring things that would only receive 12 volts when the key is on and the engine running. The center post is probably wired to the starter, giving the starter power only when cranking, with key in the start position. Does this make sense???

The power in/power out is correct. The passenger side terminal should have continuity with the battery 12V+ when the solenoid is not energized and the driver side should have continuity with battery 12V+ when the solenoid is energized.
That type of solenoid is designed to be used where the voltage you are switching is the same as the coil voltage of the solenoid, that's why there are only 3 terminals. The positive for the coil is internally jumped from the battery 12V+ terminal( passenger side) and the coil 12V- is coming from the small center terminal. To fire the solenoid you provide ground(12V-) to the small terminal and it energizes the coil and provides continuity between the 2 large terminals. Whatever is controlling the solenoid (toggle or key switch) is just providing the ground(12V-) to the solenoid coil.

 

[awynne56]

I'll check. Today .. either way you think it ok to piggy back off the hot side to a aux fuse box running about 60 amp stuff

 

[awynne56]

Wow I'm learning alot. Thanks everyone

 

[bkdraft]

Will be OK to piggy back off hot side, IF, the main feed wire from the battery is large enough to handle the load of everything attached there. Again, you need to trace all the wires and see what is attached and how much current it all draws.

 

[Living in the Past]

The power in/power out is correct. The passenger side terminal should have continuity with the battery 12V+ when the solenoid is not energized and the driver side should have continuity with battery 12V+ when the solenoid is energized.
That type of solenoid is designed to be used where the voltage you are switching is the same as the coil voltage of the solenoid, that's why there are only 3 terminals. The positive for the coil is internally jumped from the battery 12V+ terminal( passenger side) and the coil 12V- is coming from the small center terminal. To fire the solenoid you provide ground(12V-) to the small terminal and it energizes the coil and provides continuity between the 2 large terminals. Whatever is controlling the solenoid (toggle or key switch) is just providing the ground(12V-) to the solenoid coil.

My guess is the center post gets + positive 12 volts for the coil and ground is thru the housing. One of those small wires off the right side goes to the ignition switch and comes back to the center post when the key is on. Otherwise would need another relay to switch ground to the soleniod.

I'll check. Today .. either way you think it ok to piggy back off the hot side to a aux fuse box running about 60 amp stuff

Would need to know the current load of solenoid and solenoid rating to answer this.

 

[Aliveiride]

I'll check. Today .. either way you think it ok to piggy back off the hot side to a aux fuse box running about 60 amp stuff

The gauge of the wire coming from the battery along with fuse rating are the limiting factors for what can be piggybacked off that solenoid terminal. You will need to determine what is already being supplied from that wire and look up what the wire gauge is rated for. There should be a fuse or fusible link somewhere between the battery and the solenoid terminal. If there isn't a fuse, it would be a good idea to add one. If you want to add an aux fuse box that is hot all the time then it doesn't really make sense to add it to the solenoid circuit, just run the appropriate sized wire/fuse from the battery to your aux panel. If that is not feasible and you must go from the solenoid, up the size of the wire going to the solenoid and install a larger fuse. Un-fused power is never a good idea I'm my opinion.

 

[awynne56]

Yes you are all correct selioind I guessed used as a large relay? Left side always on left side on when started


Thank you all for schooling me

Andy

 

[awynne56]

Would the buss man fuse at battery terminal 150 amp the one that sits on the terminal. It's 2 awg wire... I've been reading lot of posts and everyone has a fuse on battery except ofcourse me. That will be ordered up. Thanks again everyone

Andy

 

[Downey]

Not to change the subject, but the further back the battery is positioned, the larger diameter the battery cable has to be. With your battery under the passengers seat you might want to check your battery positive cable now and then to make sure it is not heating up (which will happen if the cable is too small for the distance it has to travel). A very righteous place for your battery would have been the area where the heater blower motor was removed from.

 

[awynne56]

Downey thanks I just checked after running it and everything is a-ok wire are good. Light and everything was running sans heat ofcourse.