Thanks for the help and diagrams.
First priority is the starter circuit.
Found 3 relays involved.
0) "Isolator" (I assume added for motorhomes etc). Mounted on firwall. I assume signal from ignition switch (key on and start) will close the relay, connecting the car battery to the house battery. No information on wiring etc of this relay.
1) ignition switch sends 12V to 'starter relay' (at radiator support). That has big red 12V from battery, and the switched contact (smaller red wire) together in a "C" formed part. Signal wire (small, from ignition switch). GROUND is through contact of backside to radiator support
2) switched starter relay wire goes to "starter motor solenoid. Big red wire coming from battery. Solenoid closes to connect to battery. Ground is from housing contact to engine block.
Side note: When 'cranking' getting slower and slower, I ADDED a ground strap (for good measure, can't hurt) from one of the starter bolts to a nearby chassis bolt. Yesterday, I found this wire MELTED (still having continuity to ground).
This indicates that starter does NOT have good ground through the chassis/bolts (requiring additional amps to flow through the secondary add on wire, enough to melt it).
I removed the starter relay and tested, working fine.
I removed the starter, tested, working fine.
Next:
- clean starter relay contacts, backside and radiator support mounting area for good electrical contact
- clean starter contacts, BACKSIDE and engine block/bellhousing contact area for good electrical contact
- take both battery terminal clamps apart, clean and rewire
Need to find information on wiring the "isolator" relay.
I will double check, but I am pretty sure the Ford chassis is 1994 manufacturing year; not sure if there is a difference between 1995 and 1994.
