Engine won't shut off while headlights are on

I have multiple wiring issues lately. For starters my engines stays running after turning the key off, this only happens when I have the headlights on

Next: every time I push the brakes my radio turns off and then turns back on. This has been getting worse lately.

When I have my headlights on my radio won't turn on at all. It may flash like it wants to turn on but fails.

I have taken all the bulbs out of the front and tail lights, pulled all the fuses to see which line might be doing it, and started disconnecting wires to narrow it down.

I suspect that it is the tail lights because when I disconnect them then everything works fine. I have followed the lines back checked the bulbs and cut the entire camper line out in frustration with little change at all.

Here's where you come in: I have been searching for a wiring diagram trying to see where the line might connect. All I have found is a master schematic for a gasoline motor and a schematic for something that is similar to my truck but different enough that it doesn't match up.

I have an 85 f250 with a 6.9 non turbo. Stock wiring stock headlights no
Aftermarket relays.

If there is a chassis diagram that you think would be of some help, I would greatly appreciate a link to this knowledge. Thanks for any advice that you can pass on. My last thought is that it might be the starter solenoid but I have no freakin idea.

The Bugman

If you think it's tail light wiring related, maybe you have some trailer wiring issues.
Sounds like your lights are back feeding power in.
Check to see if you have the trailer light relays.
Also ground problems can cause all kinds of weird occurrences.

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Check your headlight switch, it may be burned up and shorting, or just get a new one.

Wow....sounds like a fire waiting to happen to me..

What year are we working with BTW...stick yer info in your signature so we know!

somethings are clearly shorting out all over in that truck...be careful and carry a good CO2 extinguisher with you JIC you set fire to truck...dry chemical is a hoo haaa to clean up so I suggest CO2 or Halon for that reason

I agree on the fire extinguisher, Carry one, and it should be CO2 or Halon (If you can still get Halon, thought I remembered it being outlawed in the states, maybe not). Make sure it is big enough too, don't carry one around the size of a can a peas and expect it to put out much more than a cigarette........

The dry chemical do a good job, but the powder is HORRIBLE to clean up. We had a Cub Cadet Garden Tractor catch fire several years ago, had a fuel leak that caught fire.... we used a dry chemical extinguisher to put it out, and I think it took 5 or 6 trips to the car wash to get all that crap out from everywhere it was hiding....... it was a nightmare.

If it is and acceptable type of fire (not oil, gas or electrical), I really like a "*** can" extinguisher. They are the big stainless steel ones with the hose and little nozzle on the side of them. They use just regular tap water, and are pressurized with an air hose. You can use them over and over and over without having to have the serviced every time. Depending on the fire, that is one of the first things we would grab off the Engine..... if it was something small, or we were investigating smoke or the like. One of those "*** cans" will put out a surprising amount of fire....... or cool down something that is hot and smoking......

This is probably just a simple ground issue. Obviously the ground to the block is good, since the engine turns over and runs. But the engine, tranny, transfer case, and rearend springs are all mounted in rubber, as well as the cab mounts. A very important ground that gets left off all the time is the one from one of the bellhousing bolts up to the firewall. If you can't find it, just add another. You can also run a new ground wire from the engine block to a clean spot on the frame. My 89 has a factory ground also from the pass side frame and clips to the bottom of the cab under the pass side door.

to add to the fire extinguisher idea, you have two batteries feeding this possible short, you may put the fire out, but if the batteries keep feeding it you will lose. Saw a truck recently that had a short under the hood causing a small fire. Fire was put out quickly, but kept coming back, because of the batteries. Three fire extinguishers later, it was a lost cause with no way to disconnect the batteries. Truck was a total loss.

Haha thanks for the fire extinguisher tips I actually don't have one so I will get on that because I would hate to lose OL Bessy.

So I took some jumper cables and grounded my batteries to the frame of the car and I got a little spark and my headlights lit up like probably twice as bright so I'm guessing I don't have my motor grounded. So am I suppose to see sparks from battery to frame. I am 100 percent sure it was the negative terminal on the battery. I am a little worried now.

Oh I changed my headlight switch a few days ago and there was no change in behavior.

1985 f250. 4 speed manual trans. 4wd. 6.9 non turbo.

Sounds like it's backfeeding to me. Maybe some wires touching somewhere. And after rereading your post I'd say a possible ground issue on top of that as well.

Doh

1985 f250. 4 speed manual trans. 4wd. 6.9 non turbo.

Do the headlights have to be on for this to happen, or does it happen with just the parking lights?

bugman40284 said:

So I took some jumper cables and grounded my batteries to the frame of the car and I got a little spark and my headlights lit up like probably twice as bright so I'm guessing I don't have my motor grounded. So am I suppose to see sparks from battery to frame. I am 100 percent sure it was the negative terminal on the battery. I am a little worried now.

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There's your problem right there. You sure will get a spark to ground, if everything is trying to find a ground through something else. The IP is probably trying to find a ground through one of the lighting circuits. It's doing well enough like that, only it's barely making it. As soon as you turn the lights on, that puts 12v on the circuit that it's using for a ground path, so that means it has 12v on both sides of the ip solenoid, and it makes the engine quit.

Run a decent sized ground wire from the block to the frame, and run another from the block to the firewall sheetmetal to ground the cab.

Ground problem.

I have a wiring diagram, PM me your email.

Thanks for the wiring diagrams and thanks for everyones input. It was the ground. Apparently I didn't put it on when I put the engine in but everything seems to be working perfect now. It was hard for me to believe at first because I've left ground straps off of other cars and never had a problem. So thanks again for your help.

1985 f250. 4 speed manual trans. 4wd. 6.9 non turbo.