Electrical Mustang won’t start.

Brad Hanks

5 Year Member
Jul 21, 2017
92
6
8
Hey, so I have a 90 with a 5 speed can’t start it with the key. ran and Drove just fine one day. Next day I go out to it won’t start with the key but will start with a screwdriver. Drove maybe two days this way. Then all it would do was blow the in-line fuse but would reset itself if I left it alone for a bit. Tried putting a fuse in the plug on the clutch switch and still would blow the inline fuse. Any advice on what to check would be great.
 
  • Sponsors (?)


Thanks to jrichker
 
  • Like
Reactions: 1 user
I tried step 4 here and it just blows the fusible link and nothing works.
Here you are saying 'blows the fusible link'
Are you taking talking about the red and blue from the clutch or the color of the fusible link? I don’t know the color of the link. I just know it keeps resetting itself.
Here you talk about it re setting itself.
The issue is a fusible link needs to be replaced, it's a wire fuse,
A relay is a little box that plugs into a wire harness
See the confusion?
 
Here you are saying 'blows the fusible link'

Here you talk about it re setting itself.
The issue is a fusible link needs to be replaced, it's a wire fuse,
A relay is a little box that plugs into a wire harness
See the confusion?
You’re right I did. Sorry. All I know Is I try it and everything goes dead. I leave it alone for a bit and everything comes back.
 
Jump down to the first video, it's a brand x truck but you should figure it out.
 
Jump down to the first video, it's a brand x truck but you should figure it out.
Thanks I’ll do it Sunday.
 
Thanks I’ll do it Sunday.

From the No Crank Checklist.....

A voltmeter is handy if you are familiar with how to use it to find bad connections. Measure the voltage drop across a connection while trying to start the car: more than .25 volts across a connection indicates a problem. The voltage drop tests need to be done while cranking the engine. It's the current flowing through a connection or wire that causes the voltage drop.

See http://assets.fluke.com/appnotes/automotive/beatbook.pdf for help for help troubleshooting voltage drops across connections and components. .

attachments\64167


Voltage drops should not exceed the following:
200 mV Wire or cable
300 mV Switch or solenoid
100 mV Ground
0.0V Connections
A voltage drop lower that spec is always acceptable.


Starter solenoid wiring for 86-91 Mustang
attachments\52294



Starter solenoid wiring 92-93 Mustang or earlier Mustang with upgraded high torque mini starter.
[
attachments\53216


The fuse links for all model years 86-93 live in the wiring harness near the starter solenoid.

64326.gif


Diagrams courtesy of Tmoss & Stang&2birds
Ignition switch wiring
IgnitionSwitchWiring.gif


Fuel, alternator, A/C and ignition wiring
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

Complete computer, actuator & sensor wiring diagram for 88-91 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

Complete computer, actuator & sensor wiring diagram for 91-93 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/91-93_5.0_EEC_Wiring_Diagram.gif

Complete computer, actuator & sensor wiring diagram for 94-95 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/94-95_5.0_EEC_Wiring_Diagram.gif
 
  • Useful
Reactions: 1 user
From the No Crank Checklist.....

A voltmeter is handy if you are familiar with how to use it to find bad connections. Measure the voltage drop across a connection while trying to start the car: more than .25 volts across a connection indicates a problem. The voltage drop tests need to be done while cranking the engine. It's the current flowing through a connection or wire that causes the voltage drop.

See http://assets.fluke.com/appnotes/automotive/beatbook.pdf for help for help troubleshooting voltage drops across connections and components. .

attachments\64167


Voltage drops should not exceed the following:
200 mV Wire or cable
300 mV Switch or solenoid
100 mV Ground
0.0V Connections
A voltage drop lower that spec is always acceptable.


Starter solenoid wiring for 86-91 Mustang
attachments\52294



Starter solenoid wiring 92-93 Mustang or earlier Mustang with upgraded high torque mini starter.
[
attachments\53216


The fuse links for all model years 86-93 live in the wiring harness near the starter solenoid.

64326.gif


Diagrams courtesy of Tmoss & Stang&2birds
Ignition switch wiring
IgnitionSwitchWiring.gif


Fuel, alternator, A/C and ignition wiring
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

Complete computer, actuator & sensor wiring diagram for 88-91 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

Complete computer, actuator & sensor wiring diagram for 91-93 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/91-93_5.0_EEC_Wiring_Diagram.gif

Complete computer, actuator & sensor wiring diagram for 94-95 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/94-95_5.0_EEC_Wiring_Diagram.gif
So I tried to do a voltage drop from solenoid to starter. I can’t get any reading because I hit the key to start and everything is dead. No voltage to anything. It’s like I took the negative battery cable off.
 
So I tried to do a voltage drop from solenoid to starter. I can’t get any reading because I hit the key to start and everything is dead. No voltage to anything. It’s like I took the negative battery cable off.
Have you cleaned both battery posts and cable clamps? They are major problem areas for a no crank condition

Voltage drop - Look at the picture - you start by measuring between the battery post and the cable clamp.
64167.gif
 
  • Useful
Reactions: 1 user
Have you cleaned both battery posts and cable clamps? They are major problem areas for a no crank condition

Voltage drop - Look at the picture - you start by measuring between the battery post and the cable clamp.
64167.gif
Oh nvm I got the wrong idea somehow thanks.
I haven’t cleaned them but both clamps and battery were replaced in September.