Centech wiring

[kdaug5]

OK, so the starter is not cranking. That really doesn’t have anything to do with the ignition coil or ballast resistor. Those are just for getting the ignition system working properly.
The lack of cranking is either something wrong with the ignition switch, the purple wire, the starter relay (solenoid), or starter, or starter cables.
So let’s do some basic testing.

Let’s make sure what we’ve got going on here.
The positive side battery cable should go to one of the large studs on the starter relay.
Sounds like you’ve got that, but just making sure.
The other large stud has a cable that goes down to the starter. No matter what color the cable is, this is not a negative. This is a positive and gets power to the starter.
But we also need to know what type of starter you have. Is it a standard Broncos starter, or more modern starter with its own solenoid on it?

Sounds good, but we need to make sure there is power to the purple/violet wire when the key is in the start position. We can test that a little later.

So that confirms that you have the battery cable connected. Do you also have the large red Centech wire connected to the same large terminal as the battery cable?
And it should have their 60 amp fuse in the red wire?
Think back then, and maybe still, they used a maxi-fuse and holder with a plastic cover.
Is that what you have?

Let’s test the starter circuit first.
With the vehicle in neutral or park, and the brake applied, (and your nerves intact and ready for surprises) jumper the starter relay to see if the starter cranks.
Be ready to be surprised just in case it actually does crank.
To jumper the relay, take a small bit of wire that you might have lying around, remove the purple wire from the S terminal, and touch your jumper wire between the battery positive side and the small S terminal.
Just doing so I should give you a major click, and the starter should crank.
If it doesn’t, we have more testing to do.
Try that and let us know what you got.

I have some work to do. I’ll be back with some results. Thank you

 

[kdaug5]

OK, so the starter is not cranking. That really doesn’t have anything to do with the ignition coil or ballast resistor. Those are just for getting the ignition system working properly.
The lack of cranking is either something wrong with the ignition switch, the purple wire, the starter relay (solenoid), or starter, or starter cables.
So let’s do some basic testing.

Let’s make sure what we’ve got going on here.
The positive side battery cable should go to one of the large studs on the starter relay.
Sounds like you’ve got that, but just making sure.
The other large stud has a cable that goes down to the starter. No matter what color the cable is, this is not a negative. This is a positive and gets power to the starter.
But we also need to know what type of starter you have. Is it a standard Broncos starter, or more modern starter with its own solenoid on it?

Sounds good, but we need to make sure there is power to the purple/violet wire when the key is in the start position. We can test that a little later.

So that confirms that you have the battery cable connected. Do you also have the large red Centech wire connected to the same large terminal as the battery cable?
And it should have their 60 amp fuse in the red wire?

I have the Centech red wire BATTERY connected positive battery cable of the starter solenoid. The red wire has the Centech fuseable link connected.

Think back then, and maybe still, they used a maxi-fuse and holder with a plastic cover.
Is that what you have?

Let’s test the starter circuit first.
With the vehicle in neutral or park, and the brake applied, (and your nerves intact and ready for surprises) jumper the starter relay to see if the starter cranks.
Be ready to be surprised just in case it actually does crank.
To jumper the relay, take a small bit of wire that you might have lying around, remove the purple wire from the S terminal, and touch your jumper wire between the battery positive side and the small S terminal.
Just doing so I should give you a major click, and the starter should crank.
If it doesn’t, we have more testing to do.
Try that and let us know what you got.

I’m the Centech harness there are 2 purple wires labeled START, one side I have to S on the solenoid, the other I have on positive side of started solenoid.

Also I’m running the old type starter.

Thanks

 

[DirtDonk]

As far as I remember, and I don’t have one of their instruction books in front of me, neither of those purple wires belongs on the red battery side.
The purple wires have one function only. That is to run from the ignition switch to the starter relay, on the little S post. Either directly, or through a neutral safety switch.
Now old Centech harnesses (and maybe current ones too?) had two separate purple wires. One is longer than the other and is meant for use with an automatic transmission neutral safety switch. The other is shorter and can be connected directly to the starter relay.

But no matter how yours is set up, remove the one purple wire from the constant battery power.
Since they are both out at the starter relay, check for power when the key is turned to START.
That helper would be an advantage here. So you could use the voltmeter or test light at the end of the purple wire, while the helper turns the key to start. Check for 12 V. I don’t think there is a fuse on that circuit, but double check.
In fact, double check that all the fuses are good.

Do you have an automatic transmission, or manual?

 

[DirtDonk]

And you’re right. I forgot Centech had a fusible link.
It’s the other companies that use a fuse, and I believe I’ve always used a maxi fuse in place of the fusible link.
Not that fusible links are not beneficial, but I feel that fuses are easier to service if ever needed.
Especially out on the trail!

 

[kdaug5]

As far as I remember, and I don’t have one of their instruction books in front of me, neither of those purple wires belongs on the red battery side.
The purple wires have one function only. That is to run from the ignition switch to the starter relay, on the little S post. Either directly, or through a neutral safety switch.
Now old Centech harnesses (and maybe current ones too?) had two separate purple wires. One is longer than the other and is meant for use with an automatic transmission neutral safety switch. The other is shorter and can be connected directly to the starter relay.

But no matter how yours is set up, remove the one purple wire from the constant battery power.
Since they are both out at the starter relay, check for power when the key is turned to START.
That helper would be an advantage here. So you could use the voltmeter or test light at the end of the purple wire, while the helper turns the key to start. Check for 12 V. I don’t think there is a fuse on that circuit, but double check.
In fact, double check that all the fuses are good.

Do you have an automatic transmission, or manual?

Yes I do have an auto transmission. I will try the volt test tonite. Thanks again

 

[kdaug5]

Well I am just trying to get the engine to crank. Body not on. Doing the minimum. I believe I have a ground problem. Trying to figure that out. Here is a pic.
Well I can’t figure out how to attach a pic.

 

[DirtDonk]

To post images, you either have to become a contributor for 12 bucks a year, use an online image hosting site such a super motors, and then link the picture to here. Or you can use your “garage”” gallery“ functions in your user CP above.

 

[DirtDonk]

Without the body on, how are you even running your harness? I know you mentioned that fact in your first post, but I totally forgot you had no body.
Are you grounding your starter relay?
Do you even want to do it with the harness? Or are you just trying to get the engine to crank? If so, you just need battery cables, and a couple of lengths of wire.
You also need to ground the starter relay. Run a wire to one of the mounting ears.

Positive battery cable to starter relay stud, other stud to starter, negative to engine block.
A negative jumper to the starter relay mounting bracket is critical to its function.
Connect to distributor to the coil however it’s supposed to be done. What type of distributor are you running? Sorry, I forgot if we already talked about that.
Power to the positive side of the coil temporarily. Don’t leave it there while you’re just puttering about because you can burn out the coil and perhaps other things. I should say power to the ballast resistor and then to the coil. Don’t let ballast resistors get near anything that can melt or burn. It gets really hot!
Run a jumper, either with a wire or metal tool of your choice, even a screwdriver, and touch the small S post on the relay to positive battery.

Unless there is a defect, your starter will crank!

 

[kdaug5]

Without the body on, how are you even running your harness? I know you mentioned that fact in your first post, but I totally forgot you had no body.
Are you grounding your starter relay?
Do you even want to do it with the harness? Or are you just trying to get the engine to crank? If so, you just need battery cables, and a couple of lengths of wire.
You also need to ground the starter relay. Run a wire to one of the mounting ears.

Positive battery cable to starter relay stud, other stud to starter, negative to engine block.
A negative jumper to the starter relay mounting bracket is critical to its function.
Connect to distributor to the coil however it’s supposed to be done. What type of distributor are you running? Sorry, I forgot if we already talked about that.
Power to the positive side of the coil temporarily. Don’t leave it there while you’re just puttering about because you can burn out the coil and perhaps other things. I should say power to the ballast resistor and then to the coil. Don’t let ballast resistors get near anything that can melt or burn. It gets really hot!
Run a jumper, either with a wire or metal tool of your choice, even a screwdriver, and touch the small S post on the relay to positive battery.

Unless there is a defect, your starter will crank!

Well thanks for the help. I have a new battery. Everything connected like you said. I can get a spark at the relay with a screwdriver but no crank and no clicking.
The body is off. The rolling chassis has been pretty much rebuilt but has sat awhile. I installed a motor and looking to just get it to crank.
Don’t get much time to work on this but I need to go a little deeper.
Thanks again

 

[DirtDonk]

When you jump the relay to get the spark, are you jumping from the battery side big terminal directly to the starter side big terminal? Or the battery to the small “S” terminal?
If jumping to the small terminal, your next test is to take a large wire, such as a jumper cable, and jump directly to the starter cable.
If you still have nothing happening, then either the engine isn’t grounded properly, the starter is defective, the engine locked up, or maybe something else.
You can eliminate the engine being locked up by turning it by hand. if it turns easily, but the starter won’t crank, you may have a defective starter, or bad cable.

To review, you should have a large negative battery cable bolted directly to the engine. Closer to the starter is better.
If you want to keep the starter relay solid, you could temporarily bolt it to the frame and run a ground wire to that bolt. Then run your cables.

Are they new cables, or old ones?