• Mustang Forums
  • 1996 - 2004 SN95 Mustang -General/Talk-
  • SN95 4.6L Mustang Tech

Bad Alternator?

  • Thread starter Thread starter JamesD87
  • Start date Start date Mar 24, 2014

JamesD87

Member
Feb 25, 2014
39
0
7
Mar 24, 2014
#1
  • Mar 24, 2014
  • #1
Alright so my battery died the other day randomly. I didn't leave any lights on or anything like that. I thought maybe there was a short somewhere but cant find one. I was thinking it was the alternator so I got online and started doing some research. I read something that said to start your car and unhook the battery and if the car dies its your alternator. So I went out there and with a booster box I jumped the car. I went to unhook the booster box and the car died...I didn't even have to unhook the battery. Is this test accurate and does it sound like that's the problem...my alternator? Thanks guys.
 

wmburns

SN Certified Technician
Aug 14, 2009
5,892
514
204
Houston Texas
Mar 24, 2014
#2
  • Mar 24, 2014
  • #2
For today's cars

No battery = No Alternator.

The first test should be the battery and battery cables. This is a PRIME symptom of a bad battery. IE, the motor randomly dies and then restarts OK.

Then have the alternator tested for correct output and excessive AC ripple (bad diode).

Bottom line. Today's cars simply will not run right without a strong battery and charging system.

The disconnect the battery to test the alternator test is a relic from the old days. The days when 30 amp alternators were the norm. Today's 100 amp alternators are different which is why the battery is so important.
 

JamesD87

Member
Feb 25, 2014
39
0
7
Mar 24, 2014
#3
  • Mar 24, 2014
  • #3
I'm pretty confident the battery is good...I bought it brand new about 2 weeks ago...do I need to remove the alternator for it to be tested or can that be done without removing it?
 

Mattstang04

15 Year Member
Sep 15, 2006
1,152
144
104
St. Louis, MO
Mar 25, 2014
#4
  • Mar 25, 2014
  • #4
If the car is driveable, take it to almost any local autoparts store. Autozone, Advance, O'Reilly's, Napa, etc. They are easily tested on the car. Have them double check that battery too.
 

JamesD87

Member
Feb 25, 2014
39
0
7
Mar 31, 2014
#5
  • Mar 31, 2014
  • #5
Just an update...I bought a new alternator that I found online and installed it Friday and all my problems have since gone away.
 
You must log in or register to reply here.

Similar threads

A
Resolved Electrical Help Please
  • Alabama
  • Jan 22, 2026
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Replies
2
Views
243
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Jan 22, 2026
AeroCoupe
B
Cant Figure Out P0340 Issue
  • Blackout67
  • May 31, 2025
  • SN95 V6 Mustang Tech
Replies
5
Views
359
SN95 V6 Mustang Tech Jun 8, 2025
Blackout67
B
F
2004 Mustang GT – Fuel Pump Not Priming
  • Fayio
  • Apr 22, 2026
  • SN95 4.6L Mustang Tech
Replies
7
Views
176
SN95 4.6L Mustang Tech Apr 27, 2026
n0v8or
N
Fox Jump/start - Charging
  • PonyGTrider
  • Oct 12, 2025
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Replies
8
Views
345
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Oct 13, 2025
PonyGTrider
Electrical Ron Francis Headlight / Alternator Harness
  • dan50
  • Apr 30, 2026
  • Fox 5.0 Mustang Tech
Replies
0
Views
179
Fox 5.0 Mustang Tech Apr 30, 2026
dan50
Share:
Bluesky Email Share Link
  • Mustang Forums
  • 1996 - 2004 SN95 Mustang -General/Talk-
  • SN95 4.6L Mustang Tech
Menu
Log in

Register

  • Forums
  • What's new
  • Media
  • Resources
  • Contact
  • Sponsor
X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?

X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?