Electrical '93 5.0 won't turn over when cold.

[evintho]

12.5v at the batt all the way to the fender solenoid. It had been running fine but suddenly, In the morning when I try to start it I get one click. I pop the hood and jump the fender solenoid from one terminal to the other, with the key on and it fires right up. Also, after I've driven it awhile and I shut it down, I try to restart it and it fires right up. I believe it's the original '93 solenoid. Does that sound like it's probably just a solenoid replacement, or could it be something else?
Everything, including the entire wiring harness is brand new or rebuilt.

 

[AeroCoupe]

Solenoid is where I would begin. A lot of the auto parts stores sell junk so be careful when buying one. This would be what I would buy:

https://www.oreillyauto.com/detail/c/blue-streak/alternators---starters/starter-solenoid/bdc3bda9b2c0/standard-ignition-blue-streak-300-amp-4-terminal-starter-solenoid/std2/ss598/v/a/5471/automotive-car-1993-ford-mustang?q=starter+solenoid&pos=3

 

[LILCBRA]

I'd check your connections to be sure they're tight and be sure that the solenoid is well grounded to the fender well.

 

[Mustang5L5]

For 1993 there are two solenoids. It's essentially a double-relay.

Take a jumper wire and jump the small upper terminal to the post with the batter connections and see if the car will crank doing that, vs bridging the two main terminals.

What i mean by that is touch your screwdriver from here to here and see if it cranks healthily. If it does, this may be an ignition switch issue

Just for reference the wiring diagram. The above relay would be labeled "starter relay"

 

[85GTStangGuy]

Solenoid is where I would begin. A lot of the auto parts stores sell junk so be careful when buying one. This would be what I would buy:

https://www.oreillyauto.com/detail/c/blue-streak/alternators---starters/starter-solenoid/bdc3bda9b2c0/standard-ignition-blue-streak-300-amp-4-terminal-starter-solenoid/std2/ss598/v/a/5471/automotive-car-1993-ford-mustang?q=starter+solenoid&pos=3

That part has quite a few bad reviews. Multiple people had issues with the plastic cracking when they were tightening down the terminal nuts.

Here's a Motorcraft option (not saying it's better necessarily, but it does have fewer bad reviews, and more good reviews... for what that's worth!)....

https://www.amazon.com/gp/product/B000C5FTKY/ref=ox_sc_act_title_1?smid=ATVPDKIKX0DER&psc=1

 

[AeroCoupe]

I had a Motorcraft fail shortly after buying. The standard has been in the car for a few years now so that’s why I recommended it.

It’s a crap shoot anymore.

 

[85GTStangGuy]

I had a Motorcraft fail shortly after buying. The standard has been in the car for a few years now so that’s why I recommended it.

And post #5 goes down in flames. Touche!

It’s a crap shoot anymore.

That's the truth. Unfortunately.

 

[evintho]

For 1993 there are two solenoids. It's essentially a double-relay.

Take a jumper wire and jump the small upper terminal to the post with the batter connections and see if the car will crank doing that, vs bridging the two main terminals.

What i mean by that is touch your screwdriver from here to here and see if it cranks healthily. If it does, this may be an ignition switch issue

Just for reference the wiring diagram. The above relay would be labeled "starter relay"

I did just that. Jumped from the small stud to batt stud, w/key on and it fired right up. Ignition switch is a new Standard Products unit and all wiring is new.

 

[Jarhead67]

Replace the solenoid, they’re cheap