Heat and ac problems
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4th Gear
Joined: Oct 2023
Posts: 4
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From: Coshocton, ohio
Heat and ac problems
2003 f250 5.4 so what's going on is this all summer truck has a ignition coil a bad code and random multiple misfire code. Fine, switched a few of the coils around, same problem. So I tried the injectors next. Same ****. Now around the same time, my ac went out, no warning nothing. It's always been ice cold. Pull the relay, add jumper wire. Compressor kicks on. Fine. Changed the relay, same problem. So one day let's say a month later. Start up the truck head to work. I notice the truck is running perfect, no miss fire and the ac is working also. It didn't last but 50 miles and started missing again. Also ac stopped working at the same time. So now that it's getting cold out I've noticed that randomly the truck has no heat, thermostat is new, full of coolant. I just drove it for an hour. Heat was working great, got home, shut off the truck for 15 minutes get back in. No heat.
Hotshot
Joined: Jan 2004
Posts: 19,760
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From: St Louis
You have two separate issues, both of which can cause apparent issues with the climate control system.
1. Severe misfires - The PCM will automatically disable the A/C compressor when this happens. Fix the misfires and the compressor operation will be restored if this is the only reason.
2. Loss of heat - Either the hot coolant is not circulating through the heater core (check the two hoses under the hood) or, if both are HOT, the temperature blending function is not working.
1. Severe misfires - The PCM will automatically disable the A/C compressor when this happens. Fix the misfires and the compressor operation will be restored if this is the only reason.
2. Loss of heat - Either the hot coolant is not circulating through the heater core (check the two hoses under the hood) or, if both are HOT, the temperature blending function is not working.
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4th Gear
Joined: Oct 2023
Posts: 4
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From: Coshocton, ohio
So update, the heat problem I got fixed 💪it was the blend door actuator.
misfire I'm still trying to figure out. But i do have updated info about it. So, I'm roughly 15000 miles ago I changed plus with motocraft plugs. So today I dissected into it. Pulled coil, plug, and injector on cylinder 1. (That's where the misfire is from)
Spark plug has almost zero wear on it and cylinder 2 and 3 both look like they should. Mind you, maybe 6000 miles ago I switched coil and injector with different cylinders to see if the misfire changed cylinders and it didn't.
So I put plugs back in it and a brand new coil on cylinder 1. Jump in, reset CEL, fire it up and drive it and still bad misfire.
so that leads me to it has to be in the COP harness somewhere.
so, where do I go from here. Where exactly do the wires run. Hoping to not have to pull the whole harness apart. Thank you! Happy Thanksgiving.
misfire I'm still trying to figure out. But i do have updated info about it. So, I'm roughly 15000 miles ago I changed plus with motocraft plugs. So today I dissected into it. Pulled coil, plug, and injector on cylinder 1. (That's where the misfire is from)
Spark plug has almost zero wear on it and cylinder 2 and 3 both look like they should. Mind you, maybe 6000 miles ago I switched coil and injector with different cylinders to see if the misfire changed cylinders and it didn't.
So I put plugs back in it and a brand new coil on cylinder 1. Jump in, reset CEL, fire it up and drive it and still bad misfire.
so that leads me to it has to be in the COP harness somewhere.
so, where do I go from here. Where exactly do the wires run. Hoping to not have to pull the whole harness apart. Thank you! Happy Thanksgiving.
Hotshot
Joined: Jan 2004
Posts: 19,760
Likes: 1,079
From: St Louis
If you'd said that sooner, you would have gotten more precise advice sooner.
You have a 1) bad COP, 2) bad PCM, or 3) bad wiring harness or connection. FWIW, the COP pigtails tend to be the most common failure for this type of problem. You'll need to ohm out the connector and harness to pinpoint the open circuit.
You have a 1) bad COP, 2) bad PCM, or 3) bad wiring harness or connection. FWIW, the COP pigtails tend to be the most common failure for this type of problem. You'll need to ohm out the connector and harness to pinpoint the open circuit.
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BlackNGoldRules
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