Keep Blowing Fuse #6 Under Dash(starter Relay Fuse) When Turning Let To Start/ Pushing Clutch In(5sp

Jordan posey

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May 29, 2017
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Car won't start, blows starter relay fuse under day every time I push clutch in and turn key to start,

I have made sure connections to starter solenoid are right.

I have traced white/pink wire from Starter solenoid to clutch safety switch( when I try to bypass the switch and put a fuse into the prongs of the switch it doesn't blow the fuse under the dash, but actually blows the fuse I put into the prongs of the CSS) this is a 5 speed manual btw.

I have made sure all grounds are good and tight, I have made sure battery terminals and good and tight/clean

I have made sure the female plug that thewhite/pink wire from Starter solenoid goes into the spade is good and clean and tight/plugged in

So I'm kinda leaning towards having a bad CSS? or possibly a pcm/ECU/ccrm problem?

I'm kinda at a loss as this is the 9th sn95 mustang I have owned and I know every inch of the electrical circuit/everything under the hood and I have put many engines in these cars

Any help would be appreciated, this is my first post btw, so thanks for having me and once again thank anybody for any help
 
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wmburns

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Aug 14, 2009
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So I'm kinda leaning towards having a bad CSS? or possibly a pcm/ECU/ccrm problem?
FWIIW, it might help to mention the model year of your Mustang. There are difference across the 1996 through 2004 model years.

Sounds like you are moving in the right direction. But are getting off track closing the deal.

First. You don't have a PCM problem. WHY? Because the 1996-2004 Mustang pilot duty starter circuit does NOT go through the PCM. In the same vein, the starter circuit does NOT go through the CCRM.

I'm having trouble believing that the CSS is bad. Why? Because IF I understand the test done, the CSS switch was disconnected and a fuse put in it's place. Therefore the CCS has been removed from the circuit but there still was excessive amp draw. So how could it be a bad CSS that's not even in the circuit?

There are tons of ways to trouble shoot this. Some are better than other's. The method used often depends upon the tools you have on hand and your electrical experience. Here's a low tech, no tool method to get you started. In the engine bay near the battery there's a single pin connector that goes directly to the starter solenoid. The wire color is usually WH/PK. Disconnect this wire. This will isolate the starter solenoid.

Now try to crank the motor.

IF the fuse does NOT blow, then you will KNOW the problem is in the starter itself or the wires leading to the starter.

IF the fuse still blows you will KNOW the short is upstream of that point. Additional tests will be needed.

A set of wiring diagrams can be a huge help tracking down a short. If interested in getting a set for yourself I maybe able to help. PM if interested.
 
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Jordan posey

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May 29, 2017
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I unplugged the white and pink wire from the starter and crosses it with a screwdriver and it cranked , so that rules out starter/ solenoid, I'm guessing it's that wire ?
 

wmburns

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Take the CSS switch out. Don't replace with anything. Does the fuse still blow?

You know that VOM's are not that expensive. Viable piece of test gear. It's not really possible to trouble shoot today's electrical cars without a VOM.
 
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Jordan posey

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May 29, 2017
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I removed the white and pink wire from starter and ran a new wire from the starter to where the single pin connector was by the battery and my car cranked 3 times, I drive down the road, came back home went inside for a little bit came back out to crank it and it blew the fuse under the dash again , the only thing I can think of is either I need to replace the wire from the single pin connector to clutch safety switch , OR it's actually the switch itself working sometimes and not working the other times , but I'm going to buy a volt meter after work and do what you said.
 

wmburns

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IF the fuse is blowing with the CSS electrical connector physically disconnected the short is in the RD/LB wire between the CSS and fuse F2.6. OBTW, it is fuse F2.6 that's blowing right?

One method to locate a ground short is to remove the fuse. But the VOM into continuity mode. Many VOM will also beep when the circuit is complete. Connect one prob to the output side of the fuse (load side). Be careful to not spread the terminals with the probe. Connect the other lead to a KNOWN good ground.

Start wiggle test by moving up and down the harness in question. When the circuit grounds out the VOM meter will beep. Pay special attention to any loose wires that may have gotten near moving parts. Also pay close attention anytime a wire passes through or near sharp metal parts.

Remember when performing resistance measurements the circuit must be dead and isolated. If there is any other voltage on the line the measurement will be in error.

Normally the odds would favor a bad CSS. The part is not all that $$ and wouldn't be all that far out to replace it just for diagnostic purposes. However I still feel the problem isn't in the CSS if the fuse still blows when the CSS is disconnected.

https://lmr.com/item/LRS-11156A/86-93-Mustang-Clutch-Pedal-Safety-Switch
 

Jordan posey

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May 29, 2017
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So I have noticed that it will crank when it's cold , but after I drive th car down the road and it warms up, it starts blowing the fuse again, which is making me think it's the starter , I just got home I'm about to check with the volt meter and post results
 

wmburns

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Aug 14, 2009
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^^^^THIS makes ZERO sense! Why? Because the starter solenoid is driven from fuse F1.3. A totally different fuse than the pilot duty fuse F2.6.

So unless all of the other trouble shooting steps posted so far were completely wrong you need to stay focused in the area already mentioned.

If the previous trouble shooting steps are in error, then start from the top and re-post the results. Expect a wild goose chase without careful well thought out trouble shooting steps.
 
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wmburns

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Aug 14, 2009
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Here's a very good video that goes through the steps and thought process needed to locate a short to ground. IMO the test can be done with a VOM meter or a smaller brake light bulb. But the concepts are VALID for the problem at hand.

Note how the tech uses the wiring diagrams to FOCUS where to look. Also note how tech was able to visually identify the problem once the wire was followed. IE by looking for burned points and physical wiring harness damage.

View: https://www.youtube.com/watch?v=G1RIXqcuNKY

Here's yet another video regarding how to locate a short to ground. This one is longer but more detailed. Again note how the wiring diagrams are used to focus trouble shooting efforts.

View: https://www.youtube.com/watch?v=FK9STP4G9-I
 
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