Mustang wont start!

So, the car was running fine but this morning I went to start it and nothing.  No clicks, no growls, just noting.  Also, no dome light, no head lights no brake lights.  I tested the battery and it is strong at 12-13 volts and still shows green on the tender.  What should I look at first?  Is there a fuse panel somewhere that would kill all power from the battery to everything?  Looking for ideas here guys...I am out of ideas! 

The car also has a Street Fire spark box installed and it is not getting any power either.  It should at least light up the diagnostic LEDS on the unit but there is nothing going to it.

Barry

Clean the terminals first

Next try another battery - I see AGM on the battery, is it a glass mat ?

I have had ATV glass mat batteries act like that where one day they are just gone.

Load test the battery.

Some basic stuff that may help....Check the battery to chassis and engine ground for a good connection. Do you get good voltage from positive battery terminal to the chassis? Will it turn over if you jump the solenoid terminals?

That's weird that pretty much everything appears to be totally dead.

Jump the solenoid terminal. If it cranks you know it is NOT the battery.

You should at least get dome lights even if the battery is weak.

Easy test is to try to jump start the car. If nothing else, as soon as you hook up the cables the done light should come one.

If it doesn't then take the jumper cables off of the doner car but leave them on your battery. Put the negative on the engine block and the positive on the starter solenoid where the postive battery cable is attached in the picture. Again, you should get at least a dome light.

I'm thinking that it would almost have to be the solenoid on the fender since the main positive cable from the battery goes to it??  I wonder how I can test the solenoid?

Your power for the car is connected at the input of the solenoid, with the battery cable, so a bad solenoid shouldn't kill all power. I would normally suggest checking the fusible links in the harness wires near the solenoid, but it looks like you may have already removed them when you put the crimp connectors on. Crimp connectors can come loose or develop oxidation in the connector if not sealed. Do you have power at the fuse block under the dash?

Steve

I agree with Steve, check the fusible links, and as Don said, clean the battery terminals. I would also clean the connections on the junction block, that looks bad.

To check the solenoid jump from the positive battery terminal to the "S" terminal on the front of the solenoid.

Boy am I glad the electrical gremlins left here but sorry they came to you, lol. If you just hot wire the car like you are going to steal it, fire to coil and short across the solenoid and see what happens. I would use another battery they do crazy things for sure.

You also said something about battery tender. I would never leave the battery hooked up in the car when not in use. a quick disconnect at the battery. You never know what can happen and with battery hooked up in car could catch fire.

My 71 did this occasionally. If I disconnected the positive from the starter and then reconnected it, power would be back. No idea why but it did work.

you tried it in park and neutral? Bad NSS might cause it not to start.

That's weird that pretty much everything appears to be totally dead.

Jump the solenoid terminal.  If it cranks you know it is NOT the battery.

You should at least get dome lights even if the battery is weak.

Easy test is to try to jump start the car.  If nothing else, as soon as you hook up the cables the done light should come one.

If it doesn't then take the jumper cables off of the doner car but leave them on your battery.  Put the negative on the engine block and the positive on the starter solenoid where the postive battery cable is attached in the picture. Again, you should get at least a dome light.

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+1 on jumping the solenoid.

I would check all the grounds.  Do you have a grounding strap between the motor and firewall?  If the motor cranks by jumping the solenoid then battery and ground is good.  If it does not crank then battery, ground on motor, starter or solenoid is bad.  Assuming motor cranks then check continuity between motor and body.  if none check the ground strap if you have one or install one if you don't have one.

If none of this work then check for voltage at the fuse box.  If you have voltage then you should have some things working at a minimum.  If no voltage check harness between solenoid and fuse box by doing a continuity check.

Boy am I glad the electrical gremlins left here but sorry they came to you, lol. If you just hot wire the car like you are going to steal it, fire to coil and short across the solenoid and see what happens. I would use another battery they do crazy things for sure.

You also said something about battery tender. I would never leave the battery hooked up in the car when not in use. a quick disconnect at the battery. You never know what can happen and with battery hooked up in car could catch fire.

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Thanks for the reminder about the quick disconnect David - especially since my car is in an attached garage.  Went out and got one last night.  Good idea that I have been lazy about doing for a while.