I would go directly to ford for this solenoid, far less problems.


E7HT-11450-A or AA

Motorcraft # SW1507B

 

My son's 89 300/6 is doing the same thing. Had to cross the factory one to get it to start, so he replaced it. Next morning the starter seized. Replaced starter and made it 1 day then the relay went out and if the battery was connected, it was spinning the starter (even with the ignition wire off). Took the 2 day old relay off and when you shake it there was a big rattle in it. Took it back and had it replaced with it's lifetime guarantee. Put the new one on, 3rd start it's doing it again.

 

Where are you getting the relays? A lifetime guarantee product is only as good as the product. It is generally recommended to use only Ford Motorcraft relays(solenoids).

 

Seems usually due to bad ground or starter cable connections.

Chinese relays have bad metallurgy. This is why the contacts weld shut.

Suppressed relays solve arc pitting but if the circuit demands excessive current the contacts are going to melt.

 

Our longest time mechanic (I work at a Ford dealership) just also said the Chinese ones generally can't handle the voltage and to get the Ford one. So that's what we shall do.

 

If you have the two smaller wires (red/blue) and black removed and it still tries to turn then the solenoid is stuck in the closed position. If you replace the solenoid and it does it again there's two possibilities. The solenoid energizing circuit is not carrying enough current to hold the solenoid fully closed. This will cause arcing in the solenoid that can lead to it sticking closed. Trace back the small red/blue and black wires and make sure that the connections are clean and secure and that they are not chaffed as was previously mentioned.

Less common with Fords but possible is a bad starter that's creating a very large load at the solenoid and welding the contacts closed.

 

I went through several Napa relays until I replaced the old stock battery cable from the positive side of the battery to the solenoid with a new heavy gauge cable.

Theory being the cables corrode internally over time and the extra resistance causes a rip in the space time continuum! and that somehow bakes the solenoid.

But I also agree parts these days aren't what they used to be. Had a shiney new vacuum advance diaphragm fail in 1,400 miles. I swapped it back out with my rusty 30 year old original. Works fine.

 

i had the same issue on my 86, somehow the f usable links got burned up and the starter solenoid, once i replaced them all it started sticking, i replaced the solenoid to no avail, check the alternator if it remains hot after the truck shuts off, mine only stopped once i put a new alternator on, after that all my electrical problems went away

 

avellanada,

If the alternator is warm or hot the diodes are blown and the battery is discharging to ground through the alternator.

The most likely cause of frying all the fusible links is connecting the battery backwards (or jumpstarting it backwards)

 

yeap a buddy jump starting backwards at work

 

Hey guys, just wanted to give you help for this problem. So once the starter gets stuck on, throw the keys out. If it is still going, grab a pair a pliers and pull off the negative cable as soon as you can to prevent even more damage to the starter/battery. Once the battery is disconnected, tap in the starter solenoid located on the passenger side fender by the battery. Now grab the negative battery cable and lightly touch it to the negative in the battery, if it zaps then you are still connected some how. If it doesn't zap then you disconnected it. So for the best chance of fixing it (what I did) you need to replace all of the big thick battery cables going to the solenoid and from the solenoid to the starter. Also replace the solenoid with a Motercraft solenoid (original brand). Clean all connections and try again. If the problems keep going then either your starter is bad and grounding to the frame, the starter has too much resistance, or your alternator is grounding causing a direct short. Hope this helped!