Ok here goes trying to explain what is going on. Started truck and moved to driveway and cut it off. Everything was fine. Went to start it again 10 minutes later nothing. Wouldnt turn over. Checked battery connections everything fine. Thought maybe shifter wasnt all the way in park jumped in pulled it up. Nothing. Went to neutral. Nothing. Ok no problem start it from solenoid. Turn switch to run screwdriver across terminals. Nothing. Turned switch back off and noticed fuel gauge was reading empty with switch on. It has over a half tank in it. Turn switch to acc and gas gauge goes up to half. Turned switch off and hit starter solenoid across terminals again with screwdriver and engine turned over like it should. MMMM bad ignition switch I thought. Pulled plug from ignition switch jumped from bat terminal to acc 1 and fuel gauge goes up. Jumper across acc 2 to bat and nothing. Jumper across acc 1, bat, and start and engine turns over but will not start. Jumper across acc 2, bat and start. Nothing I would think that one off the acc points in the ignition plug is the run side of the switch but if it is it is doing the same thing as if I was turning the key. The truck is a 78 150 4x4 so it has the big plug on the ignition switch. When I turn the switch to the on position should I have voltage at the red wire on the R side of the starter solenoid? I have voltage at the coil. Any ideas?

 

Which terminals did you jump across? The ONLY terminals you should jump across are the large stud on the battery side to the small 'S' post. Be very careful not to touch sheetmetal.

The solenoid terminals, and their function, are as follows:

1) Large stud closer to the battery. This is hot at all times because it connects directly to the battery.
2) 'S' post. The ignition switch applies 12 volts to this post when the key is turned all the way to START. This closes the solenoid.
3) 'I' post. This post is connected directly to the battery when the solenoid closes (which should be the case when you turn the key to START and apply voltage to the 'S' terminal). If the key is in RUN, you will see 6 to 7 volts at this terminal because the coil power backfeeds through the bypass circuit.
4) Large stud on the opposite side of the battery. This goes directly to the starter. Like the 'I' post, this terminal gets connected directly to the battery when the solenoid closes - except in this case, the contacts carry a lot heavier current for the starter motor.

 

Bad solenoid i believe if all of the connections and grounds are good in the wiring harness .

 

Off topic, but what part of obx are you from?

 

I agree, it's probably a bad selenoid. If it was the ignition module the truck would still turnover but wouldn't start. If the truck isn't receiving power from the battery when the key is turned but turns over when you jump some wires then something is wrong with power getting from the selenoid to the igntion switch. Def check all ground first, that has saved me some money a few times.

 

After putting a new ignition switch and solenoid on the problem was still the same. So after reading a few more threads about ignition troubles and one of the things to check was to see if the headlights were working and as I hadnt even thought about the headlights workin (I had already checked both headlight harness plugs and tail light plugs because I know these trucks will not start if they arent plugged in) I pulled the headlights on and nothing. I crawled under took the battery ground off the block made sure it was clean and checked again. Nothing. I pulled my portable steps up to the front crawled over to the back of the engine and my ground from the hood to body was good and then there it was. My ground strap from the block to the body was broken at the eye. To be sure this cant be my problem I thought. Jumped back down to the ground grabbed a jumper wire clamped one clip to the negative and touched the other clip to the radiator support and sparks. Clamped it on and we have headlights. Ran around to the drivers side and turned the key and my gas gauge started rising. Pushed the gas pedal to the floor 2 times and turned the key and that big ole 466 came to life. I had a tear in my eye. lol. After 3 days of thinking about everything that could be wrong and checking miles of wiring (it seemed like it) It was a broken ground wire. At least I didnt give up and call the crusher lol. Thanks for all the tips fellas and all I can say is for anyone messing with these old trucks dont give up on them usually it is something simple and once you find out what it was you will say damn I sure feel stupid now lol

 

Hey Patient Zero. I am in Kill Devil Hills down in Colington.

 

Very nice. I used to go out to kinnakeet every few months.

 

See "grounds" cost people money lol. Glad ya got it fixed!