Cdn991

Hey all, super strange problem. Today driving the car the AC jumped on full blast. Its cycled between hot and cold a bit but nothing would shut it down. After driving I had to leave it as I had a meeting, with the car off and keys out the ac was still blasting (or at least the fan was). When I returned 3 hours later it was still blowing air into the car.

Another hour drive home then I disconnected the battery for a minute and it went right back on when i reconnected the positive battery terminal. I am not leaving the battery disconnected for a while to see if there is a different result.

Any thoughts ?

LexVan

Year?
Any electrical mods?
Do you have a lot of other keys on your ignition key?
Spilt anything on the center console?

Strange.

I don't think the common COV issues present themselves in this way.

991carreradriver

Sounds like an ECU issue. Are you running any custom tunes? If so, suggest uninstalling. Are your cooling fans also running? Check when you reconnect the battery.

Definitely not a COV issue. When they fail, they don't present like this.

Noah Fect

Safe to say you've got a stuck relay somewhere. They are probably using solid-state switches, so it's unlikely to be a user-serviceable issue. Time to hit the dealer.

LexVan

I'd agree with this, but why wouldn't a relay's default failure be "constant off" vs the OP's "constant on"?

worf928

Relays can fail on.

Still very srange.

Your ignition switch theory is worth following.

OP: are there any other electrical accessories that are able to fuction that shouldn't be able to function with the key off?

worf928

Check the owner's manual for the location of the fuse for the HVAC fan. With that pulled, at least the fan won't drain the battery. (The Good To Know app has fuse layouts too.)

Cdn991

Thanks all. 2013 C2s.

Has Valentine 1 though ODB port and a dash cam and laser jammer hard wired. No tunes in the car at all, stock motor.

Will pull the fuse if a couple hours of no battery dont work, at least I can drive it in the mean time.

LexVan

Time to go talk to the guy that did all these electrical mods and additions. Good luck.

Cdn991

How would a 12v connection for electrical mods made months ago suddenly trip the hvac ?

LexVan

Sorry, I don't know. But I'd start the diagnostic process with anything done electrically to the car. The 991 is extremely technical when it comes to it's electrical system. The first suspected item, should be the ones you did last.

Hopefully it's something more simple like a relay.

worf928

Prima facie evidence would be if the after-market 'lectrics no longer work when the fan fuse is pulled.

Pmorritt

A year after I got my 2014 C2S the same happened, cold air constantly on and wouldn't shut off. Known problem. Took it to dealer who just replaced the COV or change over valve. There are a bank of these vacuum operated solenoids. Problem solved. Don't think it's a DIYS as they are buried in the engine compartment.

LexVan

Really? Even with the ignition off like the OP??

kwikit356

I was about to volunteer, because I thought you meant you were having trouble shooting the help. I had no clue what they might have done to deserve it, but I figured maybe they had run for cover and you were having trouble finding them. Course, it's not very fair if they're not armed. Level playing field and such.

Anyway, hope you're able to get the AC fixed without too much trouble.