• Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 Mustang Tech

Volt meter and speedometer not working????

  • Thread starter Thread starter ebk06
  • Start date Start date Oct 15, 2007
E

ebk06

Member
Feb 23, 2007
113
12
18
Oct 15, 2007
#1
  • Oct 15, 2007
  • #1
In my 87 lx the stock voltage hasnt worked since I got the car. When I start it is shoots right up to the highest reading. I replaced the cluster for other reasons and this one does the same thing. It cant be right because I've had the car for a while with no charging problems but I have no idea how to fix this. I know its not a big deal but I hate seeing it shoot right up all the time.
Next I replaced my speedo cable (old cable was melted through) and VSS sensor this weekend and it smoothed out the the speedometer a little but it still climbs way to fast and shows me going 85+ when im only doing about 50. Im guessing it the cluster since my old clusters speedo worked fine until the cable melted but just want to make sureI'm no missing something?
 

jrichker

StangNet's favorite TOOL
In Remembrance. Thank you for your contributions
Mar 10, 2000
27,512
2,811
234
Dublin GA
Oct 16, 2007
#2
  • Oct 16, 2007
  • #2
Put a digtial voltmeter across the battery while the engine is running at 1200 RPM. If you see more that 14.5 volts, you have a voltage regulator problem. All 86 and later Mustangs used an alternator with the voltage regulator buit into it. The exception to this rule is the SSI police/highway patrol cars, which may have an exteral regulator.

Your rear end gear ratio may be other than stock. That would make the speedometer read faster than you are actually going. Jack up the car and turn the rear wheel one turn and cout the number of turns the driveshaft makes. Stock gears were 2.73 or 3.08. Possible replacement gears are 3.23, 3.55, 3.73, 3.90, and 4.10. A different driven gear on the speedo cable changes the calibration of the speedometer.
 
You must log in or register to reply here.

Similar threads

Removing speedo cable from the VSS
  • 91AOD5.0LX
  • Mar 25, 2026
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • 2
Replies
27
Views
721
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Apr 25, 2026
91AOD5.0LX
J
Speedometer cable
  • Jimwbx
  • Sep 12, 2025
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Replies
1
Views
130
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Sep 12, 2025
Noobz347
Z
Right side of cluster not illuminating 91 LX Hatch
  • Zeke1995
  • Jul 21, 2025
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Replies
1
Views
128
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Jul 21, 2025
General karthief
Drivetrain Speedometer and odometer stopped working
  • AnthonyA1234
  • Oct 19, 2024
  • Fox 5.0 Mustang Tech
Replies
7
Views
474
Fox 5.0 Mustang Tech Nov 8, 2024
Noobz347
S
Engine Stalls when downshifting/coasting
  • Scott_S
  • Nov 5, 2025
  • Fox 5.0 Mustang Tech
Replies
11
Views
648
Fox 5.0 Mustang Tech Nov 6, 2025
Mustang5L5
Share:
Bluesky Email Share Link
  • Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 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?