I just recently bought a 1988 ford f350 with either the 6.9l or 7.3, i was told it was the 7.3l, 5 speed standard. Previous owners didnt give me a whole lot of detail to why it wouldnt start and said it had some wiring issues. There is no power whatsoever inside the cab. I have already bypassed a plug in the main harness because the plug was melted. Still no power, the dash cluster also looks melted so could be in kver my head. This truck is my dream tow rig and i would really appriciate some help figuring out where to look next and what to test

 

The 6.9L only needs power to the starter to start and run. Maybe do some electrical checks with your multimeter to see if you have power down to the starter, and to the starter solenoid when you turn the key.

 

So i just went and bought 2 brand new batteries for the truck and there is power to the starter, but its got power to it weather the key is on or not, im going to swap the wires around on the solenoid in the engine bay and see if thats the issue, i figure there shouldnt be a constant 12v to the starter at all

 

The 7.3L should have constant power to the starter motor contact, and a PCM operated (ground applied) relay would power the solenoid for the starter motor to crank.

 

Yeah, that just clicked in my head that there is usually a constant 12v to any starter, So when i turn the key to engage the starter the small ignition wire on the starter solenoid should have power to it correct? There isnt any power to mine, there also isnt any power to anything inside if the cab while i have the key turned to accessory, i seen there are inline fuses on the starter solenoid the go into the main harness, im wondering if one of those needs to be on the constant 12v side of the solenoid

 

Yes - when you turn the key, the starter solenoid wire should be powered.

Trace the starter solenoid wire backwards from the starter, and when you do, you will find the starter relay (passenger fender well) - many people call this your starter solenoid. You then need to test for voltage at the starter relay. You should have have power to one relay contact at all times. If you do not, then a fuse is likely to be blown, or (as in the video) there is an issue with the neutral safety switch, or the wiring. When the ignition switch is turned to crank, the starter relay should activate, and power should be supplied to the starter solenoid wire - assuming you are in park or neutral.

Do you have an owners manual for fuse location? Also, IIRC, there are fusible links in the wiring. I do not know where they would be on your year model. No doubt others would know the location and hopefully help out soon.

 

Previous owners said there are wiring problems on the truck, so it is likely there is just a broken wire grounding out or something, i will take a look at it tomorrow and see what i can find, i really appriciate the help, hopefully ill be able to get it cranking tomorrow

 

I believe it is a std shift, so might be a good move to make sure the clutch safety switch is working.

 

Well darn, I missed that.

 

I just got it figured out, the main 12v on the starter solenoid was on its own and all my fused wired for the harness were on the other side along with the starter wire, i moved all the fused ones to the constant 12v and now i have power inside the cab and can get it to crank from inside, now its just figuring out why it wont run, most likely a fuel issue which shouldnt be too difucult to figure out