Okay, I have a 78/79 f250 ranger 4x4. It has a 3512bbl NP 205/NP435 4 speed. I have had this truck for about seven years, and have never had a problem, until today. I came back from deployment for seven months, (im in the navy) and fired her right up. Nothin to it. she had been driving fine the last three days. This morning when I tried to start her, nothing, okay dead battery...right? wrong! I hooked a firebox up to her, and all she wanted to do was turn over with the key in the off position, okay Solenoid right? Wrong! I bought a Solenoid, new 1000 amp battery, cause the last one was dead anyway, and a tailamp lightbulb, and a side marker lamp bulb. I replaced the lights first, then the Solenoid. I hooked the old battery up, and then the jumpbox, nothing, the lights in the cab or under the hood dont even work. Then, I put the new battery in thinking "man this thing is really dead", I took out the voltmeter, and it read 12.74V....Ok, so did the solenoid. I have no idea what to think or do now, because to top it all off, I smacked the main positive wire onto the terminal of the battery for good measure, then the truck started turning over again.....in the OFF position.. What the heck do I do now? Its been a long while since I have been in this forum area. Anything will help at this point Im sure.. Im on base right now and am parked in a bad area, illegally, (moving a 4,250lb truck is a pain by yourself..) please respond as soon as possible. Thanks---Hardball----

 

Did you disconect the solinoid ignition wire to see if the starter would stop running ?

 

what do you mean? which one, and why would I do that? thanks..

 

Come on guys, I know shes old, and alot of you guys are into the new stuff, but isnt there anyone with any experience in the auto electric area? Im in a real jam here..

 

There should be 2 wires on the top of your solinoid the one closest to the front of the truck comes from the ignition switch. Maby it's hot all the time because of something wrong in the ignition switch.Pull it off and see if your starter stops running.
The other wire gives the ignition full battery voltage when cranking, and drops it down lower when the key is in the run position. make sure they are on the right posts the ignition is red.

 

The starter relay (solenoid) has 4 posts.
2 large
2 small
The 2 small ones are

1) *I* ignition boost of 12volts for starting engine.
2) The S Terminal for switching the relay to send big power from the battery straight to the starter.
Sometimes this connection stays locked because of cheap parts being used to make them.Unfortunately it usually gets stuck in the closed position causing the starter to keep turning.

You need to check the igintion switch for sticking.
To test this circuit without making the starter turn,disconnect the wire from the S Terminal ,

Fix a test light to the wire so you can see it out the windshield while you are in turning the switch.
Unless of course you have a helper

 

Hmmm, My solinoid is not on the starter, some folks thought it was, and another one of the probs is, is that the are some auxiliary things running off of the positive side of the solinoid ie: stereo, amp, and other stuff I'm not sure whats what. The solinoid is mounted seperatly from the starter, right next to the main battery tray. The second battery and solinoid not hooked up. The solinoid has four prongs. the first, closest to the front of the truck, is supposed to be the negative (as far as i know) There is one wire attached to it, it has an "in line fuse" on the wire towards the end, the next prong is small, it has a s on it, and I hooked up the matching boot, the next prong s also small, it has an I on it, I put the boot on it also, but not as easily. The last prong is in line with the other large prong: the first one. This is where all the red wires are hooked up. i am so confused about this stuff. Is there something wrong in my "electronic ignition"

 

my voltmeter reads 12.74 when plugged onto the solinoid terminals, ( the two main big ones) so I know there is power there. What trips me out, is that the battery will be connected, everything hooked up, but nothing will happen. No lights. No stereo. No underhood light. No Nothing, until I smack the wire end on the terminal of the battery, then nothing but the engine turning over, with a brand new solinoid? does this sound right? Could I be grounded out somewhere?I should at least have power to everything else right? There isnt the slightest trace of power anywhere visibly. I have looked everywhere and found nothing. The underdash fuse panel looks good. No burning smells or anything. And all the wiring is from the factory, this is a really clean truck. Do the wires ever tend to melt together? The wires that are wrapped together from the factory, or did something just totally screw my engine up? Does the key switch have a major role in any of this? Thanks for the help..

 

What am I looking for? all I have is a really old....but calibrated voltmeter. Thanks

 

You say the big terminal on the front of the solenoid is negative? I should be hooked up to the + post of the battery.
It also seems strange to me that all your other wires are hooked up to the back large terminal of the solenoid. It should only be "hot" when the ignition is turned to "Start" and then it feeds the starter. Your stereo etc. shouldn't work if its hooked here all the time, unless you have some serious wiring problems, and then your starter would be running all the time as well.

 

you are looking to see if the silenoid is geting power from the ignition switch.




in the picture.
big left term: battery and a smaller brown wire
the small left term: small red w/ blue stripe wire with rubber coated connector
the small right term: small brown wire with rubber coated connector
big right term: starter


take a small screw driver and use it ground the big term on the left to the little term next it, see pic.
this should activate the silenoid and start the truck if you have the igition switch on. if it works your problem is the ignition switch or somewhere in between.

 

Good idea F150Daniel. A picture is worth a 1000 words as they say.

 

Thanks for the pic, I bought an ignition switch this morning as per some mthe echanic buddies. I have yet to install it. Now as for the solinoid. Mine was set up so as you looking in this pic right now.. the ground is on left post, the two smaller posts are taken care of cause they are labled, and the post on the right has power from batt, power TO starter power for stereo, amp etc... sound wrong or impossible?

 

You shouldn't read any voltage across the two large bolts on the solenoid. They are both positive.

 

That's not right. It will burn things up like that...

The negative battery cable should be bolted to the engine block (make sure it's a clean tight connection).

Positive battery cable goes to left large stud on solinoid (as pictured above) - stereo wires would go here too. Large cable to starter goes to the right large stud on solinoid.

It's possible the way it was wired did some damage. Once the solinoid is wired correctly, there should be power at the "I" terminal with the key on. There should be power at the "S" terminal when key is in start position only. And power at the right large terminal when key is in start position only.

Check it and let us know what you find.

Marty