2019 F350 6.7L. New to me. Bought it with 46k miles and have put about 5k miles on it.
Drained coolant and installed new SPE upper and lower rad hoses, oil cooler hoses, upgraded oil cooler and SPE thermostat. Drained 6ish gallons. Pulled a vacuum on the system and pulled 6ish gallons of Motocraft coolant back in. Everything went perfect. Barely spilled a drop! Drove the truck about 30 miles with no issues at all. Go to start the truck this morning and it will not crank. Will not even attempt to crank and multiple error messages magically appear. Got "Engine Coolant Over Temp" "Full accessory power active" "service advance trac" "hill descent unavailable". Batteries are good. Replaced both batteries about two weeks ago with AGMs. Both batteries tested 12.9V.

I am scratching my head on this one. Couple weeks ago I was dealing with a 2amp parasitic draw that I traced to the gray connector by the spare tire. I felt like a champ for fixing that one and now this. I am not even sure where to start with this one. I did not mess with anything electrical at all.

Y'all got any ideas?

 

Is there a sensor that is either not connected or loose

 

I would be doing a slow and careful inspection of the areas where I was working for a wiring plug or harness issue.

 

In your other thread you said you put “a ton” of dielectric grease in the connector by the spare tire. Try cleaning it out with contact cleaner and reassembling with just a smear of grease across the surface of the female side of the connector.

Dielectric grease is an insulator and too much can inhibit good electrical connections.

 

Disconnected positive and negative leads from the batteries. Left them sitting overnight. Replaced coolant temp sensor. Cleaned out the senor plug with contact cleaner. Plugged it in and the truck fired right up!!

Maybe it was just a glitch?

 

Bingo!

Widespread misinformation out there that it conducts electricity. Its a silicone based grease that - might ? - seal out water and prevent arcing in a connector etc. Thats all.

If one smears it all over the metal pins of a connector, in order to function when reconnected, the friction fit of the male-female pin assembly needs to smear off enough grease to get a good metal to metal pin fit contact. If not, then is open circuit.

 

Well scratch that. I just went out to start the truck and all the same error messages reappeared and it will not attempt to crank. Any ideas?

 

Once my thoughtful brother decided to top off my coolant on my jeep after borrowing it for the day. It had a very slow leak that later required a water pump.

After achieving this feat with some difficulty, he went inside to relax. A few minutes later, he heard some old car in the driveway and ignored them hoping they would leave, but they persisted. Eventually, he went outside to run them off.

He was greeted by a cranking jeep engine with smoke billowing out from under the hood! He had spilled a little coolant into the fuse box while the cover was misplaced and circuits had connected unexpectedly!

Check the under hood connectors, clean each with plastic safe, non-chlorinated electrical cleaner. Allow to dry and use a very small amount of dielectric grease inside of the female connector.

FYI: My '96 Cherokee had to be rewired and it took two trips back to the dealer to correct all but one error and I fixed that one myself. The washer pumps were reversed.

 

Did the parasitic draw come back?

See if disconnecting the batteries for a bit allows it to start again. If it does that tells us something. I’m not sure what it tells us, but every clue helps find the suspect.

 

The parasitic draw has not come back. I unplugged the ecm/bcm/tcm plugs, plugged them back in and it started. I unplugged them again, blew them out, used contact cleaner on the male pulgs, small amount of dielectric on female plugs and it has started 2-3 more times since then.

We will see.

 

This truck is really kicking my ***. Took it out for a drive yesterday with the wife. First drive since I thought I had solved this electrical gremlin. Got about 10 minutes from the house, went kind of fast over a railroad crossing and immediately all the codes starting popping up and the engine died. I coasted over to the side of the road. Popped the hood, unplugged all three plugs again, had wife try to start the truck and nothing at all, totally dead. All battery connections were tight. Tried the same thing a couple more times with no luck. Disconnected the batteries, crawled under the truck looking everywhere for loose ground, etc and couldn't find anything. Reconnected batteries after 10-15 minutes, wife tried to start and got nothing. After about 45 minutes of this I gave in and called a tow truck which was about 15 minutes out. Five minutes go by and
I've given up at this point, wife hits the start button and boom it fires up! WTF!? Call the tow company, cancel the truck and we slowly drove home avoiding every bump!

Wife is saying F that truck, so that sucks. Especially when we are supposed to be taking it on a trip to Wyoming in a few months......

I am really scratching my head on this one. Been chasing gremlins for like a month now. Absolutely cannot be connected to changing the coolant. Do I just crawl around the truck cleaning and greasing every connector? Could this be tracked down with Forscan? I don't have it and suck with tech stuff anyway!!

Anyone got any ideas?

 

In your other parasitic draw thread you mentioned pulling fuses, and it sounds like this multiple error messages and truck dies was after the parasitic draw and fuse pulling investigation. I suggest going back and checking every fuse. The truck died going over railroad track bumps so it sounds like a loose or bad connection, but maybe that's a fuse. There are a few threads on the F150 forums about their fuse 27 causing somewhat similar problems.

 

After checking the fuses check for water entering the fuse box. There were some 2020 recalls on the fuse box lid not sealing. Could be water intrusion.
There has been some that had to change the BCM because of electrical gremlins.

https://www.powerstroke.org/threads/...ssues.1411748/

 

Batteries load tested?

battery terminals torqued?

 

Thanks fellas! Gonna read up on fuse 27 and double check fuse box and BCM.

Batteries are brand new AGMs with tight terminals.