Ground strap from engine to firewall gets hot while starting and then stops getting hot,
had batteries checked, replaced alternator, checked all battery connections, check all battery wire and connections, check ground from engine from block to fire wall , checked ground from battery to fender


any ideas

2003 ford excursion,

 

When you say checked, you mean took apart and cleaned?

 

Well, there's a lot of amps running around your chassis while the starter is cranking. How did you come to know the ground strap was getting hot, was someone holding it during cranking? How hot is hot?

 

yes cleaned and inspected all, reason i seen the 4x4 would not actuate, found vaccum lines melted , and noticed ground strap, i touched it and was cool , so i started engine and went back to strap and was hot, contiune to hold and it cooled down , so i had friend restart and it got hot,

 

also changed the actuator solenoid today had no vacuum thru it it worked for 15 min and stopped , maybe it got fired

 

maybe fried, and it would get hot enough to burn , that ac box, it had melted into it,

 

Might be time to see if your battery cables are swollen. Battery cables will corrode under the outer jacket and resistance will increase! Heat is a result of resistance!

 

I'd say you need to replace the ground wire...

 

Can you clarify what you mean by "checked" ?

Simply put resistance causes heat, use a multimeter to check all the connections and ground wires, I would think you have a corroded, loose, broken or missing ground wire somewhere which is causing to much resistance and the associated heat.

 

The only way that high current carrying cables can be checked for resistance is while they are under load.

They should not be getting hot, as mentioned above something is either loose or missing, possibly the starter is going bad, etc.

Here's how cables and connections are tested correctly

http://www.aa1car.com/library/voltage_drop_testing.htm

 

Replace the battery negative cable, for certain, making sure it's properly connected to a clean and secure grounding point.