No crank no start nothing happens with push button either

[SHO@Sparks]

I realized a mistake in my typing and this line should have read:

"With the bulb wired in and on, if you see the bulb go out, then the HVAC module just lost it's supplied BCM power."

 

[gavinmalone1]

If you still want to attempt to get it figured on your own, I will try to help where possible.

There are some ways you can monitor power to modules by back probing a small light into the power feed of a module, like for example the HVAC module, but it's not as easily accessed, unless you disassemble some of the dash to gain access. So, when the bulb is wired into the power circuit, you can see that it's receiving power by the bulb being lit. If while driving the bulb were to go out and it was wired into the power feed to the HVAC module, then you know that you just lost power to the module and you might find that it's unresponsive now.

In my previous response I pointed out that the HVAC nodule receives power from the BCM through Fuse F46 10 A on connector C228A pin 26. You could back probe carefully with a small pin into the back side of C228A at pin 26 and have that supply power to the small light you temporarily wired into the circuit and you would supply a ground to make the circuit complete. When you start the vehicle, that pin should now be supplied power and should stay that way until you turn the car off. You said that the HVAC can stop working while driving. With the bulb wired in and on, if you see the bulb go out, then the BCM just lost it's supplied BCM power. Hope this makes sense.

This doesn't condemn anything just yet, but it now tells you that something either in the BCM just opened the circuit or there is another issue causing it to do so.

Basically, the BCM like other modules, has power and ground, possibly a few of each, like a Hot At All Times and switched power from say an input like the ignition, then a few network connections as in MS CAN and HS CAN, followed by inputs and outputs. The BCM has a lot of control, but it relies on multiple other modules to do work too.

As Rod indicated, if you can read the networks modules live while your driving with Forscan than you can see what happens when the HVAC goes dead.

Interestingly, the HVAC panel with dual automatic temperature control, as many know, can have issues with the touch capacitive switches going nuts and driving the HVAC system into odd loops of operation, like full hot, full cold, etc.

I’m trying to see and I don’t notice forscan having a live network monitoring section if someone knows where it’s at I would love to learn. The bulb idea is definitely smart. I just wish I could be able to use ids or fdrs without having to have a vmc3 device. I was thinking of buying these clones on amazon but I heard horror stories where they really can mess up your car way more then it should so I decided not to. I’m assuming with it starting just fine in a row or it starting at all means the ms-can wires wouldn’t be something to look at but the connector could definitely be an issue.

 

[SHO@Sparks]

I’m trying to see and I don’t notice forscan having a live network monitoring section if someone knows where it’s at I would love to learn. The bulb idea is definitely smart. I just wish I could be able to use ids or fdrs without having to have a vmc3 device. I was thinking of buying these clones on amazon but I heard horror stories where they really can mess up your car way more then it should so I decided not to. I’m assuming with it starting just fine in a row or it starting at all means the ms-can wires wouldn’t be something to look at but the connector could definitely be an issue.

Your SHO is exclusively diagnosed with IDS and FDRS with the exception of APIM module updates which are done through FDRS.

I have a genuine Ford VCM 3, which is great and needed for newer Fords/Lincolns. A real VCM 3 is made in Germany. It's definitely an investment, but when you do this professionally day in and day out, it's a must.

As to buying one yourself, just a reminder that these are subscription based through Ford now and things have changed more recently as to how Ford is controlling their diagnostics even more.

Regarding wiring in a bulb to check for voltage loss....this can also be done on the power feeds to the actual BCM too. It can be a quick visual in the diagnostic process.

 

[daniel221]

Check the battery connections and main fuses first; a weak or disconnected battery can stop everything. Make sure the brake/neutral safety switch is working, as the push button won’t trigger without it. If still dead, test the starter relay/ignition switch circuit for power no click usually means no power to the relay.

 

[Paramedic Terry]

I had the exact same problem after buying my 2013 SHO three years ago. I'd only had it a month or so, when out of nowhere, it wouldn't "key on" or start. The fob would work the door locks and panic horn, but that was all. I did my own troubleshooting and found nothing. I finally had to get it towed to the local Ford dealership. After $2,000 in diagnostics, they found the gage cluster ($800) to be bad. The tech explained that it cost so much because he had to analyze each module separately. The ignition wouldn't power on, so the OBD2 port was dead.
Yes, it cost me quite a bit of money, but I had a functioning cluster and peace of mind knowing that the system was thoroughly checked out and operational.
I hope this helps.
Terry

 

[gavinmalone1]

I had the exact same problem after buying my 2013 SHO three years ago. I'd only had it a month or so, when out of nowhere, it wouldn't "key on" or start. The fob would work the door locks and panic horn, but that was all. I did my own troubleshooting and found nothing. I finally had to get it towed to the local Ford dealership. After $2,000 in diagnostics, they found the gage cluster ($800) to be bad. The tech explained that it cost so much because he had to analyze each module separately. The ignition wouldn't power on, so the OBD2 port was dead.
Yes, it cost me quite a bit of money, but I had a functioning cluster and peace of mind knowing that the system was thoroughly checked out and operational.
I hope this helps.
Terry

When this happened was it fully dead it was it intermittent?

 

[Paramedic Terry]

When this happened was it fully dead it was it intermittent?

It was working fine the night before, and the next morning; nothing. I don't know if those things can go out intermittently. Mine just quit. I would recommend taking it to the dealership to track down the problem before it quits completely. It would be cheaper & easier to analyze it by going through the OBD2 than tearing the interior apart to physically get to the modules.

 

[SHO@Sparks]

Here are a few images of the BCM circuits feeding power to some modules and of C2280A at the BCM. You can see a pin out of that connector and see how many circuits the BCM feeds from that connector. I would look closely at this connector, checking pin fit and pin drag. You can also wiggle this connector when it occurs to see if there is any resolution to the issue.

 

[robert francis]

Happened to me once last year on my 2019. Door locks worked fine but nothing on the dash would light up and I had a message about "failure to communicate" displayed. Yes, my key fob was right next to the start button. The next day I tried again - everything worked fine. I have no idea what failed.