Engine won’t shut off with key removed after ac compressor change

[bigmann245]

Update…

I think I have an issue with the alternator charging cable that runs from the alternator to the battery. The truck keeps running with the key removed but when I disconnect the 2 wire connector that is next to the battery the truck shuts off but I also have to disconnect the positive terminal on the battery for the engine to stop running. I checked with a multimeter and the wiring checks good from the connector to the alternator. This is the only connector I disconnected during the compressor swap because it was in the way when I went to lift the compressor up and out. Now I have this problem. Side note, when I bought the truck it had a bad battery. I had oreillys check the battery and alternator and they said the alternator was good but the battery was bad. I bought a new battery a few weeks ago and this problem wasn’t there till I disconnected that battery charging cable for the compressor removal. Also when the compressor seized it started to smoke because it was so hot from the belt still going around but the pulley wasn’t turning with it. I parked it and let it cool down then when I went back the serpentine belt broke under the compressor pulley cause I think it was so hot it melted it because the belt is very brittle now. I changed the belt when I changed the compressor at the same time. Not sure if any of this has to do with the engine not shutting off when they key is put in the off position and removed.

I have an 04 expedition Eddie Bauer with the 5.4l engine. The compressor seized so I swapped it out with a brand new one. I vacuumed the system and added fresh new Freon. I started it up to continue to add Freon so the ac clutch would engage. Everything works great, ac blows super cold but when I turned the key to the off position and removed it the engine continued to run. I disconnected the battery and it still wouldn’t turn off. Then I disconnected a plug that comes from the alternator that is the only plug I disconnected while changing the compressor and the engine shut off. All I disconnected during the ac compressor change was the windshield washer reservoir connectors and the one plug I mentioned that came from the alternator. I made sure to reconnect all connectors I unplugged before I started the engine. Am I missing something? It ran perfectly fine before I changed the compressor and shut off without any issues. Is there a possible connector I jarred loose or maybe something during the compressor swap that will cause this? The battery is brand new but the cables are sketchy. What can be keeping the engine running with the key removed?

 

[S20Workstation4]

I would say check your grounds....check near the A/C Compressor.

 

[whtbronco]

Well I honestly have no idea, but there is a ground on the passenger side frame rail in that area. If it's a ground issue as S20Workstation4 suggested, that would be the one to check first.

 

[pitdexion]

I would suspect the ignition switch first. (coincidence). Remove plastic on steering column to reach it and while it is running, disconnect it. If it stalls, you got it figured.
Next would be pulling any ignition related relays. One may be stuck "latched" (on).

 

[bigmann245]

I replaced the ignition switch and I still have the issue. I unplugged the connector and it still runs. I also pulled fuse #28 and the engine shuts off. I even took a flathead screwdriver and removed the switch from the steering column while it was running without the key in the cylinder and kept the ignition switch connector on and turned the switch by hand to off and it still will not turn the engine off. The only things that turn it off that I know is disconnecting the battery AND the alternator OR pulling fuse 28. I can turn the key to the accessory middle position and the lights inside come on, the fuel pump primes and the beep goes off letting me know it’s ready to crank and if I turn it back to off it all shuts off as normal. Only when I actually turn the key to start and then back to off it does not turn off the engine but it seems like it works if I just go to the accessory middle position with the key and back to off. I can also hear a click inside the fuse panel when I took the flathead and turned the ignition switch by hand back and forth to the crank position and back to the off position.

I checked continuity in the fusible link and it checks good.
I looked everywhere for any sign of a damaged wire.

This started after I put a new belt in and changed the compressor. When I started it and found out the compressor was seized and the belt broke I immediately turned the key off and the engine shut off at that time. That was the last time it turned off with the key.

So frustrating I tell ya

 

[whtbronco]

I really don't know, but I would check for any connectors that belt could have damaged or the associated wires. The crank sensor is close to the belt and the compressor, but there are several. The other thing I keep thinking is have you checked for any codes?

 

[bigmann245]

The only code that showed was battery voltage out of regs.. it’s a brand new battery and I had the battery and alternator tested at O’Reilly 2 times and the first time they said the battery was bad so I replaced it and the second time they both checked good. Here is a picture of my fuse panel. I noticed a few fuses are missing and also there is a red wire with a fuse inline that is jumping the dark green / yellow wire from one side of the fuse box to the other. What is that for?

 

[bigmann245]

One other thing to note is since buying this expedition I noticed when the fuel level gets to a certain low level it starts reading all the way full and back down to completely empty when there’s about a 1/4 or so tank left. Can the engine not shutting off be related to the fuel pump reading weird? When there’s over 1/4 tank it reads fine, just floats all up and down the indicator when it reaches 1/4 or less.

 

[whtbronco]

I can't think of how the fuel level sender could do what you described. Maybe it's sending incorrect resistance. Mine is, sometimes it exceeds the maximum value and displays nothing.

Based on your comment that your an aircraft electrician the service manual with wiring diagrams will be most helpful I think. https://charm.li/Ford/2004/

 

[bigmann245]

They would lol I just bought the truck recently and stubborn buying it… everything before the engine not shutting off was easy or just took some time chasing down. This one has me for a loop. The fuel pump and relay I know need replacing I just hope it’s somehow in some way related to the engine not shutting off with the key removed. But yea the fuel gauge fluctuates from empty to full and sometimes reads normal but it is weird

 

[whtbronco]

You got some weird stuff going on. it sure will be interesting to get it figured out. Obviously to stay running you need to maintain fuel flow so it's related, but what's maintaining spark?

 

[bigmann245]

I visually looked everywhere especially all around anywhere I was working when I swapped the compressor out. The belt did break while the engine was running so I know it didn’t fling and break anything. Smoke was coming from the compressor it got so hot when it seized so I popped the hood with engine off and saw it smoking from the compressor itself. The belt was still tight at that time. Then I left it alone for 30 min and when I went back I had my fiancé start it and then I noticed the belt was loose and broken from under the compressor pulley. When she turned the key to off it shut the engine off like it should. I tow it home, swap compressors and now it won’t shut off. Disconnected the compressor connector to make sure it wasn’t the compressor itself and still won’t turn off. I can’t even think of anything I could have done while changing the compressor that can cause the engine to stay running with key off. Swapped ignition switches still runs. Turned the ignition switch by hand with a flat head with it connected and it still runs. I may have to just bite the bullet and take it to ford and have them see. I just hate paying for diagnostics for them to say they have no idea what’s wrong. I fix one thing and bam here comes another.

One thing I did realize. The fuel relay is jumpered and the jumper has a fuse. If I pull that fuse the engine turns off BUT I can hear the rear ac blower still faintly blowing through the air vents. The front vents shut off. But if I disconnect the battery and alternator everything shuts off and resets as if I turned the key off. Something is energizing a relay somewhere. I am waiting on a replacement fuse box and will swap that and the fuel pump and fuel filter out just to make sure.

 

[whtbronco]

Swapping the fuse panel is a good idea. I'd consider removing that rigged up wiring the fuse panel as well.

 

[bigmann245]

I agree… the more I search the more it sounds like it’s the fuse box. When we towed it home I remember it rained real hard and I see that this expedition is notorious for leaking on that side into the fuse box. The new one will be here Monday so when I take the old one out I will see if it was damaged by rain and how bad. Either way it had to be changed. I don’t know why they solder those middle relays in but make the rest changeable.

 

[DieselMonk]

Check the relays… something keeps supplying power to the ECU while it shouldn’t. Get a pin out from the wiring harness to the ECU. Maybe also the BCM. Maybe it is simple as a welded closed relay or the relay doesn’t get turned off. That’s where I would start digging. Get yourself a diagram and start tracing.

 

[bigmann245]

So the more I researched the more I started to see posts about other people’s issues that were similar to mine outside of the engine not shutting off that related to the fuse box. So I dug further and saw it can also cause the engine not shutting off as well. So I swapped the fuse panel and it fixed it. The truck now turns off when the key is turned to off. It hit me that the day the compressor seized we towed it to the house and while towing it was torrential rain and realized the engine not shutting off had nothing to do with the compressor change. I thought I broke something while changing it but it was the rain. It’s hard to troubleshoot a new problem after you changed something and it’s completely not related. But I am so glad I found it. The owner before me jumped the fuel relay with a wire that had a fuse inline. I already knew the fuel relay was bad just by that but trying to figure out why the engine wouldn’t shut off threw me for a loop. It was also draining my battery dead. The fuse box had multiple issues. Such a ****** design and poor placement right where water leaks in. Now to find the leak. Probably the sun roof drains.

Thank you everyone for your input and help. I learned a lot about the electrical system while chasing this gremlin. Fun and frustrating at the same time.