Comma AI self driver assistant

[purplelimo]

Hi all,

I just received my C4 and installed with inline coupler and sliding dock, and noticed that when my C4 is removed from dock that A/C does not work. If I unplug the long USB from the Comma harness, then A/C works again.

Has anyone else experience this?

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[chriserx]

Hi all,

I just received my C4 and installed with inline coupler and sliding dock, and noticed that when my C4 is removed from dock that A/C does not work. If I unplug the long USB from the Comma harness, then A/C works again.

Has anyone else experience this?

Yes, you probably have the coupler backwards. Turn it around and report back.

 

[purplelimo]

Yes, you probably have the coupler backwards. Turn it around and report back.

This is definitely not the case as I have the coupler hooked up lightning bolt to long cable and comma to short cable.

But just for sh*ts and giggles, I flipped it and saw all the errors light up as well as A/C still not functional.

 

[UncleTony]

This is definitely not the case as I have the coupler hooked up lightning bolt to long cable and comma to short cable.

But just for sh*ts and giggles, I flipped it and saw all the errors light up as well as A/C still not functional.

That is generally from the connectors not being plugged in all the way. Try rotating the end of the long cable (just the connector, not the entire cable) 180 degrees and plugging it back into the coupler. It generally gives a snap when it seats all the way. If the end breaks off, you’ve gone too far.

 

[purplelimo]

I’ve tried reinserting the cables and I am inserting them such that they give that very satisfying click.

The weird thing about my situation is that everything behaves normally when C4 is docked/installed. No errors from car, A/C works normally. It’s just that for the shorter drives where I leave the C4 at home that A/C is not working.

 

[UncleTony]

I’ve tried reinserting the cables and I am inserting them such that they give that very satisfying click.

The weird thing about my situation is that everything behaves normally when C4 is docked/installed. No errors from car, A/C works normally. It’s just that for the shorter drives where I leave the C4 at home that A/C is not working.

It has been a little while since it’s come up. But I recall the 24s having the ac issue specifically. From what I remember it was related to the comma power being plugged in and we later found that it was related to the long comma cable having an issue.

In the situation you leave the c4 at home and have the AC issues, do you also have the errors on the dash and do you have the coupler installed in that scenario?

 

[purplelimo]

It has been a little while since it’s come up. But I recall the 24s having the ac issue specifically. From what I remember it was related to the comma power being plugged in and we later found that it was related to the long comma cable having an issue.

In the situation you leave the c4 at home and have the AC issues, do you also have the errors on the dash and do you have the coupler installed in that scenario?

Without Comma plugged in, there are no errors and everything seems normal other than A/C doesn’t ever kick on.

I did one other experiment, which is to also unplug just the coupler (and short cable). In this case, I get all the errors!

One thing I haven’t tried is to unplug the OBD2 cable. Maybe I should try this since you mention a power problem?

 

[UncleTony]

Without Comma plugged in, there are no errors and everything seems normal other than A/C doesn’t ever kick on.

I did one other experiment, which is to also unplug just the coupler (and short cable). In this case, I get all the errors!

One thing I haven’t tried is to unplug the OBD2 cable. Maybe I should try this since you mention a power problem?

It’s not really a power problem. The OBD power comma uses also has can in it and it adds a resistance to the setup from the OBD port. I would try unplugging it and see what it does. The comma will just take a little bit longer to boot. If that fixes the issue, I can suggest a new long cable

 

[BluesClues]

Finished the install of C4 but got a bunch of faults on boot. Service Advanctrac (bsm, parking etc)

I put the coupler in the right way so I’m a bit surprised. Any ideas?

 

[Ajzride]

Finished the install of C4 but got a bunch of faults on boot. Service Advanctrac (bsm, parking etc)

I put the coupler in the right way so I’m a bit surprised. Any ideas?

#1,586

#1,563

 

[BluesClues]

#1,586

#1,563

flipping the connector caused the vehicle to become unknown - I assume I just try to force it as an F150?

edit

flipped the long side first.
Now flipping the short side

 

[UncleTony]

flipping the connector caused the vehicle to become unknown - I assume I just try to force it as an F150?

What does the unknown message say? Unknown variant or Dashcam mode?

 

[BluesClues]

What does the unknown message say? Unknown variant or Dashcam mode?

it said dashcam mode then I saw it say unknown variant

after flipping short side, it says dashcam mode.

 

[UncleTony]

it said dashcam mode then I saw it say unknown variant

after flipping short side, it says dashcam mode.

Force the fingerprint to a lightning and you should be good to go.

 

[Ajzride]

it said dashcam mode then I saw it say unknown variant

after flipping short side, it says dashcam mode.

https://bluepilot.dev/2026/03/26/the-beginners-guide-to-bluepilot-on-ford-vehicles/

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