No Crank With Key

[CB93COBRA]

Engine doesn't crank with key, I've checked the solenoid it works fine.

I've tested for power, and I get power at the ignition wire (pink/white), but none, at any wire at the Clutch Safety Switch, it seems there should be power to at least 1 wire in the red/light blue group with power regardless of clutch position. I assume there is a short or break in the line someplace in between.

Are there any fuses that could cause this? I had a hard time tracing the wire from the ignition, it terminates into a larger all black wire and there are others next to it that make it difficult to follow, but I'm pretty sure I finally found it.

It goes into a black box with all the wires tagged and labeled with numbers on one side and description on the other. Then black wires come out the other side of the box. The pink/white wire traces to #4 labeled "Starter output +12V" I get 12v with key in Start position.

The other numbers are as follows:
2 Constant 12V 5A, it gets 12V to it with key in on position
3 Starter Input 12V I don't get any power at on, or start position
5 Ignition Input 12V I get 12V at on and Start
6 Ignition Output 12V I get no power at any key position
7 Earth
8 Earth
I see no label for 1

There are 4 screws that hold together the box all the wires go into it looks like it may just be some sort of wire organizer, the way it's put together, but I don't want to mess anything up by pulling it apart.

I'm hoping somebody has some knowledge of all this and can help me out, I don't see any bad connections, but it seems there must be one someplace. the car had been parked for a few months since last starting it and when I went to move it this last time it was a no go.

 

[jrichker]

No Crank checklist for 5.0 Mustangs

Revised 05-Oct-2010 to update Fluke references.

No crank. slow crank and stuck starter solenoid problems have the same root causes – low battery voltage and poor connections. For that reason, they are grouped together.
Use the same initial group of tests to find the root cause of both no crank and stuck solenoid problems.

Since some of the tests will bypass the safety interlocks, make sure that the car is in neutral and the parking brake is set. Becoming a pancake isn’t part of the repair process…

1.) Will the car start if it is jumped? Then clean battery terminals and check battery for low charge and dead cells. A good battery will measure 12-13 volts at full charge with the ignition switch in the Run position but without the engine running.
A voltmeter placed across the battery terminals should show a minimum of 9.5-10 volts when the ignition switch is turned to the Start position and the starter engages or tries to engage. Less than this will result in a clicking solenoid, or slow cranking (if it cranks at all) or a starter solenoid that sticks and welds the contacts together.

Most auto parts stores will check your battery for free. It does not have to be installed in the car to have it checked; you can carry it with you to the auto parts store.

The battery posts and inside of the battery post terminals should be scraped clean with a knife or battery post cleaner tool. This little trick will fix a surprising number of no start problems.

The clamp on with 2 bolts battery terminal ends are a know problem causer. Any place you see green on a copper wire is corrosion. Corrosion gets in the clamped joint and works its way up the wire under the insulation. Corroded connections do not conduct electricity well. Avoid them like the plague...

If the starter solenoid welds the contacts, then the starter will attempt to run anytime there is power in the battery. The cables and solenoid will get very hot, and may even start smoking. The temporary fix for a welded starter solenoid is to disconnect the battery and smack the back of the solenoid housing a sharp blow with a hammer. This may cause the contacts to unstuck and work normally for a while.

A voltmeter is handy if you are familiar with how to use it to find bad connections. Measure the voltage drop across a connection while trying to start the car: more than .5 volts across a connection indicates a problem.

See http://assets.fluke.com/appnotes/automotive/beatbook.pdf for help for help troubleshooting voltage drops across connections and components. .

2.) Check the battery to engine block ground down near the oil filter, and the ground behind the engine to the firewall. All grounds should be clean and shiny. Use some sandpaper to clean them up.

3.) Jump the big terminals on the starter solenoid next to the battery with a screwdriver - watch out for the sparks! If the engine cranks, the starter and power wiring is good. The starter relay is also known as a starter solenoid.

The rest of the tech note only concerns no crank problems. If your problem was a stuck solenoid, go back to step 1.

4.) Then pull the small push on connector (small red/blue wire) off the starter solenoid (Looks like it is stuck on a screw). Then jump between the screw and the terminal that is connected to the battery. If it cranks, the relay is good and your problem is in the rest of the circuit.

5.) Remember to check the ignition switch, neutral safety switch on auto trans and the clutch safety switch on manual trans cars. If they are good, then you have wiring problems.

Typical start circuit...
Diagram courtesy of Tmoss & Stang&2birds

6.) Pull the starter and take it to AutoZone or Pep Boys and have them test it. Starter fails test, then replace it. If you got this far, the starter is probably bad.


Starter solenoid wiring for 86-91 Mustang

Starter solenoid wiring 92-93 Mustang or earlier Mustang with upgraded high torque mini starter.

Electrical checks for the switches and starter solenoid

Remove the small red/blue wire from the starter solenoid. Use a screwdriver to bridge the connection from the battery positive connection on the starter solenoid to the small screw where the red/blue wire was connected. The starter should crank the engine. If it does not, the starter solenoid is defective.

If the starter does crank the engine, the problem is in the clutch safety circuit (5 speed) or Neutral Sense Switch (auto trans) or ignition switch.


Typical start circuit...
Diagram courtesy of Tmoss & Stang&2birds

You will need a voltmeter or test lamp for the rest of the checks. Connect one lead of the voltmeter or test lamp to ground. The other lead will connect to the item under test.
Look for 12 volts on the white/pink wire when the ignition switch is turned to the Start position. Check the ignition switch first.
No 12 volts, replace the ignition switch.

The next step will require you to push the clutch pedal to the floor (5 speed) or put the transmission in neutral (auto trans) while the ignition switch is turned to the Start position.
Good 12 volts, check the clutch safety switch (5 speed) or Neutral Sense Switch (auto trans) for good 12 volts on both sides of the switches. No 12 volts on both sides of the switch and the switches are defective or out of adjustment. Check the wiring for bad connections while you are at it.

 

[CB93COBRA]

I was hoping for more specific info on where the wires route, and where a likely break would occur. I've done all the testing I can, I've seen the info you posted many times in searches, that's why I posted as much info as possible in my original, hoping somebody would read it all and have a suggestion on where to go from here.

I wouldn't have bothered posting another no crank post if I hadn't searched and done everything I could already.

Battery is new, terminals are new, solenoid works as per the instructions above (removing blue/red wire and jumping), Power is good at pink/ white wire, but none at any of the blue/red wire going to clutch.

No power even going to the CSS tells me there is a problem between the IGN wire and the CSS, am I wrong here?

 

[jrichker]

Sorry, if you searched, you also found that very few people will tackle electrical problems over the Internet. Unless someone else is feeling daring, I am the last and only resource.

CSS - are you referring to the Clutch Interrupt Switch shown on the diagram? Blue/red wire? Are we looking at the same diagram?

 

[CB93COBRA]

Yes, Clutch Interrupt. Have seen it labeled Clutch Safety Switch, hence CSS, sorry for the confusion.

I wasn't exactly looking for a diagnosis I was just hoping somebody had specific info on wire routing from previous experience, or knowlege of a fuse if one existed, I don't see one in the diagram, but in my mind it didn't mean there could be one tied to it someplace.

Am I correct in assuming that there should be power at one side of the plug for the Interrupt switch with key at start?

 

[liljoe07]

With the clutch pedal up, yes. Down, both will have power. Sounds like you have some sort of aftermarket alarm on the car. The black box you speak of is not factory.

 

[CB93COBRA]

I'm guessing Pink/White going to a black wire isn't factory either?

That makes sense, and gives me some options to look at for diagnosing further.

Thank you both for the help.

 

[liljoe07]

I'm guessing Pink/White going to a black wire isn't factory either?

Nope, thats not factory either.

 

[CB93COBRA]

Great... I mean now I have a clue about what could be going on, was really hoping somebody would have some insight as to the wiring that helps a lot to know where aftermarket starts.

I thought it a bit odd that a say 16 ga pink/white went to what looks more like a 12 ga solid black wire, but I haven't had any experience looking at the factory unmolested wiring on a mustang before.

 

[liljoe07]

Great... I mean now I have a clue about what could be going on, was really hoping somebody would have some insight as to the wiring that helps a lot to know where aftermarket starts.

I thought it a bit odd that a say 16 ga pink/white went to what looks more like a 12 ga solid black wire, but I haven't had any experience looking at the factory unmolested wiring on a mustang before.

It may even be a remote start deal. Not sure. And it could be either that or an Alarm. Either way, you should be able to trace down the other side of the white/pink wire. It looks to me like they have the labels mixed up. And it might be adding to the confusion. You are getting 12v in crank, at the starter output wire. If that was correct, the engine should be cranking over. Since its not, you could probably assume its actually an input. And the the one thats labeled Input, should be the output. Confused yet? LoL

You could try taking a spare piece of wire, and bypassing the box, by connecting the wires for Starter Input and output together. Then try it the key and see if it cranks over.

 

[jrichker]

It may even be a remote start deal. Not sure. And it could be either that or an Alarm. Either way, you should be able to trace down the other side of the white/pink wire. It looks to me like they have the labels mixed up. And it might be adding to the confusion. You are getting 12v in crank, at the starter output wire. If that was correct, the engine should be cranking over. Since its not, you could probably assume its actually an input. And the the one thats labeled Input, should be the output. Confused yet? LoL

You could try taking a spare piece of wire, and bypassing the box, by connecting the wires for Starter Input and output together. Then try it the key and see if it cranks over.

That's what I like about Stangnet: sometimes a different view can add a great deal of clarity and thought when trying to solve a problem. I am glad some one else decided to jump into the fray to help you get this problem resolved. It is a community effort.

 

[CB93COBRA]

I thought the labels seemed weird at least the one for the ign wire.

No remote start, I'm guessing either a bad connection from the alarm side, or maybe a fuse on that end, it seemed to unlock the doors with the remote, so initially I assumed the starter circuit was good, and didn't even really think about the alarm being an issue past that, I guess I just had some tunnel vision going on.

Once the alarm was mentioned, I about slapped my forehead and thought "duh" the alarm would probably have a starter lock out to keep it from getting stolen.

Thanks again!!