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2005 V6 Mustang (automatic) - electrical gremlins and repair advice

995 views 2 replies 3 participants last post by  Mnuckolls 
#1 ·
Hey everyone, I've seen bits and pieces of this issue come up a couple times but was having trouble finding resolutions to it so I was hoping to get some advice.

My Mustang is now 10 years old and has always had some issues. I've had a battery drain fixed, I've replaced my alternator once, front struts twice, and the battery probably 3-4 times (excessive, I know). I also have some weird issues like my speedometer setting 40mph to the new zero (usually on cold mornings), my gas gauge getting pinned way past full, or having to fill up by inverting the nozzle when putting it into my tank. However, I've never had an issue this sever.

The other day I was driving along and then my radio shut off, giving me a "low battery" message. Then, I noticed my AC was no longer working, it was just blowing hot air. Soon after that it shut off entirely. Naturally, I tried to roll down the windows so I wasn't sweating too profusely but alas those didn't work either. I also noticed that my ABS and traction control lights were on on the instrument cluster (no check engine light or anything). Okay, so at this point I figure I should get home before it gets worse. So I make a turn to go home and now my blinker wont shut off. A few minutes later, it starts making that beeping sound for when the door is open or seat belt isn't on. My car is actually crying to me at this point. Shortly after that, my whole instrument cluster goes dead. No gauge is giving any reading, every electrical thing in the car is just off. Luckily, it all comes back after about a minutes but it's still showing ABS and TCS lights and no other systems are working. Luckily, I'm almost home. Just as I'm about to turn onto my street, my car kinda had a little hiccup, it felt like I pushed a clutch in then release it kinda quick and EVERYTHING magically started working again. It was like nothing ever happened. I took it to a mechanic and spend $200 for them to tell me they couldn't find anything wrong other than a low battery.

Fast forward three weeks, the same thing happened again! This time, it never got to the point of fully fixing itself and now I can't start my car (wont turn over). Windows stutter when I try to lower them and I can see lights flickering and hear things clicking as I hold the window button.

tl;dr: All my electrical (radio, AC, windows, ABS, TCS, instrument cluster, etc.) took a **** then randomly fixed itself for three weeks. Now they all took a **** again, leaving me covered in **** without a car. Mechanics are baffled.

My question is: Does this sound like an alternator issue? The mechanic that checked it before said the wires were fine and the output looked good but that it might be "worn" and that could lead to "intermittent issues." Is it worth paying the $300-$500 to replace my alternator and cross my fingers or does it sound like more of a short issue where I'll have to replace my cluster?
 
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#2 ·
Could be the alternator, battery or if they check out ok, more likely the Smart Junction Box. It's behind the kick panel on the passenger side. Pull the panel and check for moisture. Known problem on our ponys.

So a search on AFM for SJB and/or Smart Junction Box. Lots of threads..
 
#3 ·
Being an intermittent problem, that is also systemic (affecting all systems) I would start with checking the battery connections, and the positive one at the back of the alternator. it could also be a loose connection at the junction (fuse) block.. hope this helps.
Typically if an alternator stator (the part that spins inside the case) is worn, it'll have a tell tale whine, that increases with engine RPM. the whine is from the bearings that hold the stator. another common noise would be "marbles in a can", that might be fairly quiet... this is either a total bearing failure, or from internal grime, grit, and bits if internals bouncing around as the stator spins around. usually you can judge this condition by fluctuating voltage at the back of the alternator. other than that, the inside of an alternator is just a bunch of magnets wrapped in copper wire (not much to fail there), and then the control board which houses the sensitive electronics (possible issues could arise here, and they would cause a fluctuation in performance.
if it happens again, have a Volt meter, and test at the back of the alternator, and watch for jumps in voltage, or even worse, switching (positive to negative, or AC) voltage. that would point to the control board one way diodes failing, and a need for a new alternator.
 
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