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relay, switch, and solenoid - same things?

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Old Apr 8, 2004 | 10:15 AM
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relay, switch, and solenoid - same things?

Hey all - an amateur mechanic here, looking to learn as much as I can about my 75 f100.

1st question - is the starter solenoid the same thing as the starter switch? what about the relay? if not, where do I locate these things. What about the neutral starter switch? I'd like to replace all parts of the ignition system

I've replaced my battery, starter, solenoid, and battery cables, but still can't get the engine to crank...it just clicks.

...short description of truck and problem: I Think it's a 302 V8 with edelbrock heads and edelbrock 4-bbl, auto trans - good running shape, although I don't know much about its history. I just got the truck a couple days ago and haven't had time to check the block for a code. Anyway - truck drove great for the couple days that I've had it, but when I stopped to get gas, I couldn't get it started again. Tried beating on the starter and checked all the wires. At first, I got a little crank from the engine, but then only clicks.

now after replacing starter, solenoid and battery cables, I still only get clicks.

ANY help would be appreciated.

thanks! - xminust
 
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Old Apr 8, 2004 | 10:28 AM
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Welcome to FTE... Sounds like a good truck.

First I'd use a ratchet/socket on the crank bolt and check that the engine will turn over by hand. This will eliminate engine damage.

Make sure the battery is fully charged and the connections are clean and tight - especially the ground to the block. Use a voltmeter or test light and check that there is power at the starter when you turn key to 'start'.

Let us know what you find.

Marty
 
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Old Apr 8, 2004 | 11:05 AM
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thanks!

thanks - I will!

xminust
 
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Old Apr 8, 2004 | 04:05 PM
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From: Houston/Hope BC
If you are still interested:
a switch is a manually operated device, it can be momentary or maintained in all kind of varios pole configurations. You have a combination ignition and starter switch that the key goes into.
A relay is an electically operated switch composed of a coil and a set of contacts. You have a starter relay, technically speaking, but calling it a solenoid will not get you the wrong part.
A solenoid is a coil that moves an armature to perform some kind of mechanical work. A GM starter has an solenoid that operates the throw-out lever to engage the gear, and, incidentally, is also a relay, because it sends the high-current to the starter windings.
The neutral safety switch is down by the trans linkage, but I don't know if it is internel or external, it connects to a two-pin connector up near the back of the engine. This is the ideal place to jump around it... it is a closed curcuit to enable starting.
 
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Old Apr 9, 2004 | 09:28 AM
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yes...thanks for the info. very helpful.

but, what do you mean when you talk about "jumping around" ? How do I bypass or jump around one of these components? what size wire or cable do I need to use?

thanks for the help

chris
 
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Old Apr 9, 2004 | 12:01 PM
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From: Houston/Hope BC
It is really hard to teach basic electric concepts/troubleshooting in this format, perhaps the library where you live might have something. But to answer the specific question on the neutral switch: pull apart the connector and shove some wire it it. This completes the curcuit for starting.

Use the same or a larger guage wire than whatever you are working on, smaller will make a "fuseable link"; you may of heard of these, they are a manufacturer's charity program for mechanics.
 
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Old Apr 9, 2004 | 02:21 PM
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thanks - will do.
 
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Old Apr 9, 2004 | 02:29 PM
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Ignition switch = The Starter Switch

Starter Relay = Starter Solenoid

The Combination Neutral Safety Switch/ Back-up lights switch is just that.
When the curcuit is closed power is allowed to go through the switch to the starter relay/solenoid.
Your NSS/BULS is located on the steering column, just under the dash.
 
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Old Apr 9, 2004 | 02:53 PM
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thanks!

so when my back-up lights go out, does this indicate a problem with my starting circuit? or vice versa?
 
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Old Apr 9, 2004 | 03:05 PM
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No.

They are 2 different circuits, but the current is sent from the same place
 
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Old Apr 9, 2004 | 03:48 PM
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From: Houston/Hope BC
They are two independent sets of contacts (switches, if you like). Dennis may know if they reside in the same housing and be subject to a common failure mode, but, generally speaking, IMO, no.

Dennis, thanks for correcting me on the location, mine has always been out and I assumed the connector went down to the transmission, I would have swore there were some connectors down there on my C6.

more on the solenoid vs relay fun: http://www.carcarecouncil.org/Electrical/solenoid.shtml

And not to whip a dead horse, but technically (an this is a technical fourm), the keyswitch (the right name for it) is an ignition switch and a starter switch in one unit, an ignition switch (the part that turns the ignition system on) in a maintained device and a starter switch (that signals the starter) is a momentary device. Yes, they are in the same housing now, but in the early days we had a physically seperate switch for each. Sure, the parts man will give you the right thing whichever you ask for and we use the names interchangably, but I wanted X to get a clear understanding of what what was going on; and hopefully, correct nomenclature. Thanks, hope I don't sound like a nit-picky jerk.
 
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