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

79' Electrical Issues

  • Thread starter Thread starter 93CalypsoConvert
  • Start date Start date Aug 16, 2022
  • Tags Tags
    electrical

93CalypsoConvert

Active Member
Nov 26, 2020
275
91
38
Virginia
Aug 16, 2022
#1
  • Aug 16, 2022
  • #1
Well one fox just wasn't enough. I recently picked up a 79 5.0 notch that has been sitting in a field for 21 years. I've got it running and yard driving, but I'm having some electrical issues.

The first is ignition. I must hot wire the coil in order to keep it running. It gets +12 while cranking, but is lost when the key is in run position. It has an ICM (duraspark II maybe?) and a traditional coil. I'm unsure if there is supposed to be a ballast resistor in this system.

Second is power to accessories. When the key is in run, none of the electronics work (blinkers, wipers, radio, blower motor) with the exception of headlights. However, once the engine is running and alternator is turning, everything works. Battery power doesn't seem to be reaching the electronics. Battery DOES charge though...

If anyone has pictures of how the ignition is supposed to look, that would be great. Going to look though my Haynes manual tonight and see if that leads me anywhere.
 

limp

wrap a little cheese around it and its a done
5 Year Member
Oct 4, 2020
5,454
2,888
173
Florida
Aug 16, 2022
#2
  • Aug 16, 2022
  • #2
Have you checked your grounds?? A 21 year field car must have a fair amount of at least superficial rust and corrosion.....
 

93CalypsoConvert

Active Member
Nov 26, 2020
275
91
38
Virginia
Aug 16, 2022
#3
  • Aug 16, 2022
  • #3
No I haven't. Thats a great point. Will do that tomorrow.
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
27,826
10,507
203
polk county florida
Aug 16, 2022
#4
  • Aug 16, 2022
  • #4
I think those years suffer from the same, although less frequent, ignition switch problem, not the key switch, the one under the dash.
Also the fuse link wire at the starter may be suspect.
 
Reactions: 93CalypsoConvert

93CalypsoConvert

Active Member
Nov 26, 2020
275
91
38
Virginia
Aug 17, 2022
#5
  • Aug 17, 2022
  • #5
You were right. A tab on the ignition switch had broken off and half of it was hanging down. Holding it up tight fixes both of the problems above. Thanks.
 
Reactions: Potomus Pete and limp

Mr.Kelley

Active Member
Aug 9, 2019
194
117
53
San Diego Ca
Aug 17, 2022
#6
  • Aug 17, 2022
  • #6
Check for rodent damage also. Chewed wires are a PITA to chase down and replace.
Glad you got it fixed. I'd still check....21 years in a field
 
Reactions: limp

93CalypsoConvert

Active Member
Nov 26, 2020
275
91
38
Virginia
Aug 17, 2022
#7
  • Aug 17, 2022
  • #7
Well I got lucky with rodent damage. The car was the home to at least three garter snakes. Maybe more. Counted a total of 7 snake skins in the interior lol.
 

limp

wrap a little cheese around it and its a done
5 Year Member
Oct 4, 2020
5,454
2,888
173
Florida
Aug 17, 2022
#8
  • Aug 17, 2022
  • #8
General karthief said:
I think those years suffer from the same, although less frequent, ignition switch problem, not the key switch, the one under the dash.
Also the fuse link wire at the starter may be suspect.
Click to expand...
General, do you have a picture of what you are talking about?? Thanks...
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
27,826
10,507
203
polk county florida
Aug 17, 2022
#9
  • Aug 17, 2022
  • #9
Look under the dash on the steering column.
 
Reactions: limp

limp

wrap a little cheese around it and its a done
5 Year Member
Oct 4, 2020
5,454
2,888
173
Florida
Aug 17, 2022
#10
  • Aug 17, 2022
  • #10
is this it? What do you look for on a bad one?? Plastic separating from the metal??
TY
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
27,826
10,507
203
polk county florida
Aug 17, 2022
#11
  • Aug 17, 2022
  • #11
Plastic part loose, slide sticky, the early models were less problematic.
 

limp

wrap a little cheese around it and its a done
5 Year Member
Oct 4, 2020
5,454
2,888
173
Florida
Aug 17, 2022
#12
  • Aug 17, 2022
  • #12
General karthief said:
Plastic part loose, slide sticky, the early models were less problematic.
Click to expand...
thanks......
 
You must log in or register to reply here.

Similar threads

H
New Built 91 Foxbody electrical failure. Need help
  • hassler
  • Aug 18, 2025
  • Fox 5.0 Mustang Tech
Replies
8
Views
437
Fox 5.0 Mustang Tech Aug 21, 2025
limp
T
2002 V6 3.8L Help Me
  • TheIncompetentMechanic
  • Apr 4, 2026
  • 1996 - 2004 SN95 Mustang -General/Talk-
  • 2 3
Replies
50
Views
657
1996 - 2004 SN95 Mustang -General/Talk- May 12, 2026
TheIncompetentMechanic
T
89 LX Electrical Troubles
  • fun331
  • Oct 25, 2025
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Replies
5
Views
316
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Nov 27, 2025
fun331
P
Crank but no start BUT no power to gauges
  • project_88LX
  • Jan 13, 2025
  • Fox 5.0 Mustang Tech
Replies
5
Views
506
Fox 5.0 Mustang Tech Jan 14, 2025
Mcmahst
Drivetrain 83’ Glx convertible C5 Trans help!
  • JacksonJared2113
  • Dec 25, 2025
  • Fox 5.0 Mustang Tech
Replies
2
Views
319
Fox 5.0 Mustang Tech Dec 26, 2025
JacksonJared2113
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?