Starter solenoid wiring

[Danno]

Ashamed to ask this but here goes...........is it possible to have the pos and neg cables/wiring on the solenoid hooked up wrong and the car still start and run?

I ask this because when I got the car the PO had his homemade alt harness and connections hooked up to the solenoid. That was not bad enough, so he installed the solenoid upside down on the firewall and bent the bracket so the hood would close I guess.

I have since disconnected the wiring and repositioned the solenoid and straightened the bracket, and reconnected the wiring. Now every picture I see of a solenoid the positive connections are on the fwd post and the black cable is on the aft post, just opposite of what I have from my repair of his handiwork.

When I first got the car the upside down solenoid had the pos connections: on the front...if you can visualize...flipping it over puts the connections on the back..........I am grabbing at straws here, but the car has always started and run fine...........

 

[will e]

There are no negative wires.

When installed normally the large post near the batterry gets hooked up direct to the battery.

The large post on tbe otber side goes to the starter. Technically I think you could swap these.

The small post near tbe battery is what engages the solenoid. This gets 12v positive from tbe ignition switch when the switch is in the start position.

The other small post gets energized when the solenoid and typically is use to supply 12v to the coil during cranking.

If the small posts are reversed the solenoid will not work


Actually it might not work if you swap the large posts. This might cause the small12v to be energized all of the time. (Car won't stop running)

 

[BrandonDindorf]

This is correct, the only reason for the placement of power vs acc is how the contacts make connections. It's a longer life out of the relay. Some get ground through the main metal housing to the car (in most cases), some have wiring. But this is an easy determination. The engine is actually the negative side of that circuit.

 

[Danno]

There are no negative wires.

When installed normally the large post near the batterry gets hooked up direct to the battery.

The large post on tbe otber side goes to the starter. Technically I think you could swap these.

The small post near tbe battery is what engages the solenoid. This gets 12v positive from tbe ignition switch when the switch is in the start position.

The other small post gets energized when the solenoid and typically is use to supply 12v to the coil during cranking.

If the small posts are reversed the solenoid will not work


Actually it might not work if you swap the large posts. This might cause the small12v to be energized all of the time. (Car won't stop running)

What I have, is the fwd solenoid post, (nearest to the battery) has only the black cable going to the starter on it, the other post is connected to the pos battery cable, (red), there is also the larger yellow wire with a fuseable link and one more smaller yellow wire connected to it. The small posts must be ok 'cause it starts ok.

 

[jeff8877]

Here is a pic of what should look like...hope this helps.

Jeff

 

[Danno]

Here is a pic of what should look like...hope this helps.

Jeff

That is exactly opposite of what I have, and looks like every other picture I have seen. One question. do you have 3 connections on the fwd post, 2 yellow and the red positive cable?

 

[will e]

Danno, Don't be ashamed to have asked.

Here is the situation with electrical systems, especially on 40 year old cars.

1. Someone has messed with it.

2. You can't trust the colors of the wires to really mean anything, especially with the battery cables (I know, I once tried to jump start a car and assumed the red wire was positive, the black was neg. Not good)

3. Multi-meters are your friend.

4. Pictures are good but they won't replace a basic understanding of how the electrical system works and how each component operates.

Spend some time researching how a DC (Direct Current) electrical system works. Learn how each component operates too. You don't have to be an expert. I can explain 'how' to hook up a solinoid, a coil, a relay but I couldn't explain how each of them works.

I am not trying to be harsh. I am relaying my experience. Believe me, I have fried wires, batteries, caused small fires, etc. You can create a lot of trouble (and expense) for yourself messing with the electrical system if you don't understand how it works.

 

[Danno]

Danno, Don't be ashamed to have asked.

Here is the situation with electrical systems, especially on 40 year old cars.

1. Someone has messed with it.

2. You can't trust the colors of the wires to really mean anything, especially with the battery cables (I know, I once tried to jump start a car and assumed the red wire was positive, the black was neg. Not good)

3. Multi-meters are your friend.

4. Pictures are good but they won't replace a basic understanding of how the electrical system works and how each component operates.

Spend some time researching how a DC (Direct Current) electrical system works. Learn how each component operates too. You don't have to be an expert. I can explain 'how' to hook up a solinoid, a coil, a relay but I couldn't explain how each of them works.

I am not trying to be harsh. I am relaying my experience. Believe me, I have fried wires, batteries, caused small fires, etc. You can create a lot of trouble (and expense) for yourself messing with the electrical system if you don't understand how it works.

I appreciate your input, I have a good idea of how a 12v dc system works, and I have a test light and a vom that I use religiously. I was just given an electrical nightmare by the PO. Being that I never had any problems before the alt harness change, I never really looked at what mess I had in the engine compt. I worked from the trunk forward last winter, starting with a severely butchered taillight harness I sent to MIDLIFE. I should have figured that was only the start of the gremlins.

NOW I have an alternator that is warm too long after I shut the engine down. Went out today and the battery was 2 volts, something is dragging it down over night, but this never happened before, even over the winter I was able to start the car whenever I wanted to. I wonder if I have a couple of problems going on? I also noticed 'something" floating in one of the battery cells yesterday. Since I never had the caps off this is the first time I have seen this. Prolly a cell coming apart. I probably shouldn't, but I for troubleshooting I am recharging it just to get the car running again,

and I also switched the cables on the solenoid. I confirmed that the vr plug wires were going to the correct posts on the alt. I have narrowed it down to maybe a bad alt ground, the cables being switched on the solenoid, ( but they were always like that), or just a bad harness. BTW no offense taken.:s

 

[will e]

Cool, thanks Danno.

Check the battery voltage (for reference)

I would test the solinoid. With it all hooked up you should have current battery voltage at one large post and no voltage at the rest. It might be that the small 12v post to the coil is remaining on (I think this one is marked "I"). This could be draining your battery.

I would then disconnect the big post to the starter side. Apply positive current to the small terminal closest to the battery, I believe it is marked 's'. THen test the other small post as well as the starter side large post. These both should have 'battery voltage'.

 

[midlife]

Cool, thanks Danno.

Check the battery voltage (for reference)

I would test the solinoid. With it all hooked up you should have current battery voltage at one large post and no voltage at the rest. It might be that the small 12v post to the coil is remaining on (I think this one is marked "I"). This could be draining your battery.

I would then disconnect the big post to the starter side. Apply positive current to the small terminal closest to the battery, I believe it is marked 's'. THen test the other small post as well as the starter side large post. These both should have 'battery voltage'.

Disconnect all wires from the starter solenoid before performing this test. If you apply voltage to the S terminal, the starter could engage...

 

[grey169]

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HELP???!!?!?!


I would first like to thank everyone in advance for the answers to my questions.

 


I know that in the morning I will figure it our but I thought that I would ask for help in case I can't figure it out.

 


I had also purchases a cobble job of wiring from someone. I have since been rebuilding it but I do not remember how it was wired for the strarter. Please tell me what I have wrong or need to add to make the starter engage.

 


The positive post of the battery goes to the left side of the solenoid.


The ground of the battery goes to the engine block.


The right right side of the solenoid goes to the starter.

 


Do I have this correct?

 


Please help. I have a 71 mach 1 with a 351C.

 

[midlife]

[/font]

 

 

 


The positive post of the battery goes to the left side of the solenoid.


The ground of the battery goes to the engine block.


The right right side of the solenoid goes to the starter.

 


Do I have this correct?

 


Please help. I have a 71 mach 1 with a 351C.

That is correct.

 

[73vertproject]

[/font]

 

 

 


The positive post of the battery goes to the left side of the solenoid.


The ground of the battery goes to the engine block.


The right right side of the solenoid goes to the starter.

 


Do I have this correct?

 


Please help. I have a 71 mach 1 with a 351C.

That is correct.

 


+1