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Electrical Help me find a missing connection

  • Thread starter Thread starter Xavierg208
  • Start date Start date Feb 15, 2026
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Xavierg208

New Member
Nov 14, 2025
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Feb 15, 2026
#1
  • Feb 15, 2026
  • #1
I’m working on finishing up a rebuild that was unfinished and can’t seem to find where this pigtail connects to. It is located on the passenger side strut tower coming from the same harness as the MAF sensor. Any help is appreciated.

Edit: it is a 1991 mustang 5.0
 

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Last edited: Feb 15, 2026

AeroCoupe

lube between the nut and the face. I know my lubes
Founding Member
Oct 28, 2001
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Feb 15, 2026
#2
  • Feb 15, 2026
  • #2
If I had to guess it would be the O2 sensor connector. Would help to know what year car and a picture showing the color of the wires going into the connector.
 
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Xavierg208

New Member
Nov 14, 2025
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Feb 15, 2026
#3
  • Feb 15, 2026
  • #3
AeroCoupe said:
If I had to guess it would be the O2 sensor connector. Would help to know what year car and a picture showing the color of the wires going into the connector.
Click to expand...
Sorry got too ahead of myself. Original post is updated it’s a 91 mustang 5.0
 

Mcmahst

5 Year Member
Jan 19, 2021
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Laguna Woods CA, fort Mohave AZ
Feb 15, 2026
#4
  • Feb 15, 2026
  • #4
What are the color of the wires going to the connector. That’s the only way to be sure what it’s for.
 

85GTStangGuy

5 Year Member
May 19, 2021
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Feb 16, 2026
#5
  • Feb 16, 2026
  • #5
Xavierg208 said:
.... Any help is appreciated.

Edit: it is a 1991 mustang 5.0
Click to expand...

11 x 17 COLOR Wiring Diagram for Ford 1985 Mustang (Fox Body) US Spec 4 pgs | eBay

Make & Model: Ford Mustang (Fox Body Style). YOU WILL GET A DIAGRAM - NO MATTER WHAT. Prospero's Wiring Diagrams presents 11 x 17 - Bigger than other wiring diagrams. The Quick and Dirty on Our Wiring Diagrams.
www.ebay.com


Pardon Our Interruption...




Edit - correct link provided.
 
Last edited: Feb 17, 2026

AeroCoupe

lube between the nut and the face. I know my lubes
Founding Member
Oct 28, 2001
5,923
4,042
183
Claremore, OK
Feb 16, 2026
#6
  • Feb 16, 2026
  • #6
I think the link you posted is for a 1985.

11 x 17 COLOR Wiring Diagram for Ford 1991 Mustang (Fox Body) US Spec 7 pgs | eBay

Make & Model: Ford Mustang (Fox Body Style). YOU WILL GET A DIAGRAM - NO MATTER WHAT. Prospero's Wiring Diagrams presents 11 x 17 - Bigger than other wiring diagrams. The Quick and Dirty on Our Wiring Diagrams.
ebay.us
 

85GTStangGuy

5 Year Member
May 19, 2021
1,002
625
133
Jax, Florida
Feb 17, 2026
#7
  • Feb 17, 2026
  • #7
AeroCoupe said:
I think the link you posted is for a 1985.

11 x 17 COLOR Wiring Diagram for Ford 1991 Mustang (Fox Body) US Spec 7 pgs | eBay

Make & Model: Ford Mustang (Fox Body Style). YOU WILL GET A DIAGRAM - NO MATTER WHAT. Prospero's Wiring Diagrams presents 11 x 17 - Bigger than other wiring diagrams. The Quick and Dirty on Our Wiring Diagrams.
ebay.us
Click to expand...

Thanks. Fixt the post.

Grabbed the wrong link in my rush....
 

Mustang5L5

That is…until I whipped out my Bissell
Mod Dude
Feb 18, 2001
43,260
17,945
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Massachusetts
Feb 17, 2026
#8
  • Feb 17, 2026
  • #8
O2 sensor harness connector would be my guess based on location, but need to see wire colors
 

Mcmahst

5 Year Member
Jan 19, 2021
686
270
83
Laguna Woods CA, fort Mohave AZ
Feb 17, 2026
#9
  • Feb 17, 2026
  • #9
The HEGO harness, at least on my 88 5.0, is the only 8 pin connector on the engine. Mine is located at the back of the engine. Wire color will confirm.
 
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