Yesterday I parked my v8 Vantage after an uneventful drive. I just walked past it 24 hours after that and heard the radiator fan spinning up in a quiet "whoosh" and then spinning back down. I was pretty confused and tried to open the door, then the keyfob wasn't working. I manually unlocked the car triggering the alarm (first time I ever heard it). I was just barely able to start it (battery was almost dead).

It's now running and I'm letting it idle for a while to charge the battery, but I am confused as hell as to what might be going on here.

Any thoughts?

 

Dang, I let it idle for a while, and now the power will not shut off when I pull the key out! All the dash cluster lights and stereo are staying on, and warning light says "alarm activated".

 

I will give that a shot. I took it for a 15 minute drive and things were still acting crazy. Shut the car down, all light stayed on - ran through system check (without the key in (?)), then repeatedly tried to open the fuel door with a bunch of lights flickering. I started it up again and drove 10 minutes more, I heard some crazy sounds coming from the radiator fan, then pulled over and let it calm down.

After the noise stopped I drove 20 minutes more towards home, where I was able to park it and have everything shut off normally. I replaces the keyfob battery with a new 2032 battery (seemed like it was failing), and everything seems to be normal for now.

A lot of this I can attribute to the battery being drained; but the crazy loud fan noise is bothering me a bunch. Seems like there has to be a mechanical issue for that noise to occur. And still curious why the radiator fan would keep running in the first place.

 

I don't get it. Today I just walked past my car and the fan is running at full speed. Has anyone heard of this before? The outside temperature isn't even hot. The car has been off for LITERALLY 24 HOURS. How the hell is it possible for the fan to decide to just start running?

 

I suspect a relay that is bad - it may be intermittent, but after use, it just doesn't pop back to the off position. Simple (and pretty easy I think) - unless it it a PWM design. There was a thread previously about the modules going bad and the mfg. out of business. I think someone replaced it with a Jaguar module. - here is the thread:

https://www.6speedonline.com/forums/...ting-fans.html

 

Definitely sounds like some kind of electrical issue. A bad relay seems like a good place to start. I don't know if the fan relay is some place easily accessible under the hood or not. Hopefully somebody else knows.

 

Had a chance to look at the wiring diagram and there is a fuse for the radiator fan in the underhood fuse box, but all that does is feed power to the fan modulator. The fan modulator serves as the relay. It would seem possible the modulator is what has gone bad and the link posted has the info for replacing it.

 

Thanks a lot. I will check this out, I've been keeping the battery unplugged for the time being. Do you know if the wiring diagram is available for download somewhere?

 

You could just remove the fuse for the fans. You'll probably get a spark if the fans are still on when you plug it back in; may want to use a glove or pliers. It was labeled as F35 in my manual, but I have a 2013. It'll be bigger than the regular fuses since the fans draw a lot current.

I got hard copy manuals off Ebay. Not cheap, but I like having the hard copies. Just search on Ebay.

 

This sounds like an issue that plauges certain BMW's with a similar fan setup as our AM's. The fans are driven by a module or controller - My Vantage has a BTM fan controller - which you can learn about in detail in this thread, including low cost replacement: I am not sure what setup vehicles >2010 came with but it is likely a similar setup with an ECU controlled PWM signal to a fan module or controller:

https://www.6speedonline.com/forums/...ting-fans.html

The fan setup is designed to operate even with ignition off - this is to cool the engine after a heat surge when you turn off the car after a spirited drive. When the fan module starts to fail often the fan will remain on (or come on overnight) draining the battery. (on the BMW's - but it is the same setup for many Ford, Volvo & Jags etc.) I have replaced fan modules in a few of my bimmers with compatible modules from Volvo and Ford vehicles.

Like I said the fan module in our AM"s follows the same logic as BMW and many Ford controlled vehicles. The ECU determines the fan output speed based on many input factors that include coolant temp, speed, ambient temp etc. The fan module controls the speed via a PWM signal from ECU. When a little moisture gets inside the fan module housing the electronics go haywire and that is most often when the fan comes on long after shutdown.

If you want to understand more about the logic of fan modules I put this doc together for BMW owners but it is the exact same logic for many Ford vehicles as the design is actually from Bosch and is also employed by Johnson Controls & Siemens.

BMW-North Electric Fan Guide


Edit: Last thing - check that the coolant temp sensor is functioning properly - although this is normally an issue when the vehicle is running (fails to drive the fan at the correct speed) the Coolant temp sensor is typically the primary input for fan speed and activation. If you measure across the two contact points of the CTS at cold then hot there should be a difference greater than 200 ohms for a functioning temp sensor. I doubt the CTS is the issue but due diligence and all since I am not as familiar with the AM logic.

 

I'm not 100% sure that this is the same issue, but I just fixed a similar issue on a V8 Vantage that shares a lot of electronic parts with your car.

The fan would come on full speed when the key was off and out of the ignition, with a 360 beat per minute or so clicking from one of the fuse boxes.

Here's a link to the thread I responded to in detail, I think you need the underhood fuse box.

https://www.6speedonline.com/forums/...ngine-off.html

 

First thing I would do is get a new battery. No testing is going to be believable with a weak/poor condition battery. It does sound like a fan relay, module or temp sensor is malfunctioning? Any of the three might not work properly without the proper voltage. It might even take a hard reset ? Good luck, electrical bugs are a pain!