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

Fox Lost all gauge cluster function after Holley Terminator X install

  • Thread starter Thread starter Justin17383
  • Start date Start date Monday at 4:57 PM
  • Tags Tags
    dash board foxbody foxbody 5.0
J

Justin17383

New Member
Nov 9, 2026
1
0
1
United States
Monday at 4:57 PM
#1
  • Monday at 4:57 PM
  • #1
I recently installed a Holley Terminator X on my 1987 Foxbody and lost all gauge cluster function including Battery reference, coolant temp, oil pressure, tach, and fuel level.

I cut the two plugs from my old harness the Grey and Black one i think they're called c110 and I hooked them up as follows.

Gray plug
  1. I have the Green/Yellow and the white tach wire from the Holley TFI pigtail plugged into the negative side of the coil.
  2. I have the Red/Green plugged into the positive side of the coil.
Black Plug
  1. I have the Red/White and White/Red hooked up to there designated sensors.

*******My lights work on the dash including turn signal indicators, headlights, etc.*******

I have no issues on the Holley side my ECU reads RPM just fine and i have no issues starting my car. I'm not sure if i shorted my dash or when i removed the engine harness i removed some sort of common ground for the cluster. If anyone has ran it a similar issue or knows a way for me to test the cluster that would be helpful.

Thanks, Justin
 
Last edited: Monday at 6:42 PM

Kid wita 5oh

I'm definitely not in the original hole
Founding Member
Nov 5, 2000
1,415
154
93
Saugus, MA
Wednesday at 7:37 PM
#2
  • Wednesday at 7:37 PM
  • #2
Sounds like you physically cut the wires to the cluster.
When I did my Holley install I made a custom sensor harness (with the correct plugs ) to plug into the two body harness connectors (both round 6 or 8 pin, I don't remember)
Everything worked perfectly
 

AeroCoupe

lube between the nut and the face. I know my lubes
Founding Member
Oct 28, 2001
6,222
4,317
183
Claremore, OK
Wednesday at 7:57 PM
#3
  • Wednesday at 7:57 PM
  • #3
You need a wiring diagram for an 87 to figure out what all needs to be reconnected at the two plugs.
 
Reactions: LILCBRA

LILCBRA

I wish I didn't have all of these balls in the air
Mod Dude
Dec 6, 2005
6,630
5,658
194
Corn County USA
Wednesday at 8:05 PM
#4
  • Wednesday at 8:05 PM
  • #4
I have these and highly recommend them if you're looking to pick some up. They can also be found on Ebay.

Ford 1987 Mustang (Fox Body) US Spec 6 pages

Prospero's Wiring Diagrams presents: 11 x 17, Laminated, Full Color Wiring Diagrams for Motorcycles & Vintage Sports Cars! PROSPERO'S WIRING DIAGRAMS offers the Sports Car Enthusiast the finest color wiring diagrams available. Our diagrams are accurate and easy to use - they are based on Factory...
colorwiringdiagrams.com
 
You must log in or register to reply here.

Similar threads

M
1996 GT Speedometer electrical nightmare
  • moon96gt
  • Oct 7, 2026
  • SN95 4.6L Mustang Tech
Replies
2
Views
168
SN95 4.6L Mustang Tech Oct 17, 2026
CAMTWO1070
S
Preparation for Holley Terminator X install – Foxbody 306 (electrical fan, alternator, MSD Ignition, etc)
  • So_Flo
  • Mar 1, 2026
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • 2
Replies
22
Views
3K
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Mar 4, 2026
General karthief
Resolved Holley terminator integration into CCRM
  • BrandonMP
  • Feb 25, 2026
  • SN95 4.6L Mustang Tech
Replies
8
Views
583
SN95 4.6L Mustang Tech Aug 23, 2026
fasterthangas
F
J
Engine Tuning...?
  • justadude07
  • May 30, 2026
  • Fox 5.0 Mustang Tech
Replies
8
Views
379
Fox 5.0 Mustang Tech Aug 21, 2026
Qtrhrse23
F
3G Alternator install question
  • fathead429
  • Oct 24, 2026
  • 1974 - 1978 Mustang II Talk & Tech
Replies
7
Views
245
1974 - 1978 Mustang II Talk & Tech Oct 25, 2026
LILCBRA
Share:
Bluesky Email Share Link
  • Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
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?