sonnier

Over the past few weeks, my 06 GT has developed an intermittent starting issue. Over the past year I have upgraded the head unit(soldered all connections), replaced speakers, I upgraded the battery to an Optima red top just a few months ago. All these changes were in the car and everything was working fine for quite a while so I don't believe any of it may be my cause.

All of a sudden, a few weeks ago my Mustang refuses to start. It was at my in-laws so I left it there and came back to jump start it later but when I went to jump start it, I tried the key first and if fired right up. A week later it happens again but this time at a local Target. I try to jump the car and that doesn't work but all electrical systems are working fine, I hear the starter relay click even. I ended up push starting the car and that worked and got me home.

I figured I had a starter issue, so pulled it and brought it to Autozone. They tested it and it worked fine. I figured maybe it only happens sporadically like when it gets hot and I've got 51k miles on the car so I'll spend the money and just pop in a new one to eliminate that as the possible cause. I get her all buttoned up and still no start.

I woke up the following morning and figured I would put it in the shop. Went to start it hoping I wouldn't have to push start and it fired right up. I brought it to my buddy's shop and he figured it to be the starter relay, so we swapped that out.

It's been working fine for a week and half but then this morning it wouldn't start again, so I'm stuck driving my wife's Beetle to work. I turn the key and it clicks (the relay by the sound of it). All other electrical works fine.

I think I've eliminated most of what could be my cause(s) so I'm scratching my head on this one. I suppose I could get the battery tested but I don't think that's the problem. All the changes I've made prior to this happening have functioned properly and at 51k, this is the first problem I've had with the car. From the research I've done, and I've done quite a bit of searching on different Mustang forums and even google, I've addressed the components that could be causing this. The only thing left could be the part in the steering column that syncs with the key perhaps. I've even tried both of my keys and get the same no start result.

I'm at loss. Any ideas before I bring it to the dealership?

wayne613

Plenty of ideas..
Only 1 of them is the problem though.

http://iihs.net/fsm/?dir=40&viewfile...g%20System.pdf (wiring diagram)
http://iihs.net/fsm/?dir=206&viewfil...g%20System.pdf (service manual)

If you don't get the normal clicking sound from insufficient power, the lights don't dim even slightly, then power isn't getting to the starter. There are only a few things that can be the culprit in this case, you've already checked the first couple, the one that stands out, coming to mind right away is:

Switch, or wiring from switch (not being fully pushed in for one reason or another, happened to others)
a. Digital transmission range(TR) sensor (automatic transmission only)
b. Clutch pedal position (CPP) switch (manual transmission only)

Mr.Ski

How old is that battery....?

wayne613

Second sentence, first paragraph...

sonnier

I guess I should have noted that it is a manual, this is why push starting worked on it.

I have yet to get a multimeter to check wiring/switch.
I'll also have to check the clutch pedal position switch (I had that issue in a Honda Civic before)
I haven't noticed the PATS light come on so I'm hoping that isn't the issue.

wayne613

Yeah, I yanked that, upon thinking about it for more than a second, if you can push/jump-start, you're good there.

Switch seems likely with the symptoms. Jump in, doesn't start, come back, do exact same thing, works without a hitch. Either due to switch going bad, or perhaps being slightly out of place now so it doesn't always get fully depressed.

sonnier

I may just go buy a sensor since they are cheap just to eliminate that as a possible cause.

Damn I hate crawling under dashes, they just don't make them easy for ample gentlemen such as myself.

sonnier

I pulled the switch and upon inspection, it looks physically okay. I'm burnt out from a long day at work or else I'd jumper the circuit to verify if the switch is bad or not but then again a new one from Rockauto is only like $20.

wayne613

The few that I've seen on the forums where this was the culprit wasn't due to the switch itself, but from it being recessed back over time so that it no longer worked every time. Most macGuyver'ed something to the housing. Otherwise, replacing the entire assembly is the "approved" fix.

sonnier

I ordered a new one so I'll update once that comes in. At least I have another car to drive while the Mustang is down.