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Headlights and Instrument panel turning off and on on their own!

2006 Chrysler 300 Limited. Very strange issue here. If the ignition key is turned on, and the headlight switch in ANY position (auto, off, parking, or on) the headlights and fog lights turn off and on on their own! No rhyme or reason to it. At first if the headlight switch was in the “auto” position, it wouldn’t give me a problem. Now I can’t shut the headlights off, the foglights off, or “flick” the high beams on by pulling the “multi-function” switch back. Long story short, i think the actual headlight switch might be faulty, but the multi-function switch not making the headlights do anything is what is making me second guess this issue. Does anybody have any ideas on where else I should look? Fuses are all fine. Thanks in advance!

The CCN (Cabin Compartment Node) receives a signal from the headlight switch then the light on request is sent to the FCM (Front Control Module) which activates the exterior light relays.
The multifunction switch sends the dimmer request directly to the FCM.

If the CCN or FCM detect a fault like an open circuit signal from the headlight switch the headlights will be on when the ignition is on as a fail safe.

This is not a DIY type repair, about all you can do is check that the headlight switch is fully connected. A dealer level scan tool will be needed to check the system for faults.

Can you imagine, 30-40 years from now someone trying to restore one of these cars as a hobby?? As more and more complaints like this are registered on this board, you wonder if car owners will be able to get 10 years out of them before electronic failures send them to the scrapper…

I suppose, as a last resort, you could bypass the electronic controls and direct-wire the lights with standard replacement switches…

LOL, No I can’t imagine that, Caddy.
You’re right: Maybe the only way to keep those things running that long is to direct wire everything, do everything old school, using relays and by going back to using a carb and points.

NO NO PLEASE NO CARBS!

Thank you Nevada. That stuff is way beyond me. I do understand what you are talking about and it all makes sense, however I don’t think I want to dig that far into it. Looks like it needs to see the dealer for this one. Ughhhh…not what I wanted to do. Before I do that I will check and maybe even replace the switch. Carquest has them brand new from 45 bucks. Cheaper than paying 105 for an hour at the dealer, plus parts. So once again, thank you!

If you feel like experimenting remove and reinstall the Front Control Module. This is the silver module attatched to the under hood fuse box. If this temporarily restores the headlights to normal the problem may be the FCM. This is a common problem on the Caravan but less on the 300.

A new FCM is $212.75 from moparonlineparts.com

Nevada_545 has a great reputation here for good advice, so bet on what he says.

My two cents, I had a car – an older car, well, like Tommy, that’s the only kind I have :wink: – where the dashboard and head lights would come on and go off like they were hooked up to the emergency flasher. Just parking there on the side of the road. On and off. Continuous flashing. Two seconds on, two seconds off.

I wondered what could cause the lights to flash like this. Then I traced the wiring out and discovered there was a low ohm short in one of the head light fixtures. The flashing was caused by the circuit breaker which protected the circuit. The short caused the lights to be “on” all the time. The circuit breaker would turn on , and the lights would come on, then it would detect the short, and turn the circuit off. After the circuit breaker cooled down, it would turn back on again. On and off it went. My neighbor said my car looked like a Christmas tree.

Rube Goldberg is alive and well in Detroit. What is the logic to sticking a computer into a very simple circuit. Was the old circuit just too reliable for Chrysler?

With multiplexing and a $300 module they are able to save $5 worth of copper wire. There are other benifits but it doesn’t seem to add up to the expence and complexity of the late model systems.

Many late modle vehicles rely on computers to control exterior lighting.

Here is the diagram/layout for the 2008 Toyota Camry;

Nevada, when you say “remove and re-install”, Do you mean literally take the FCM out of the car, or just unplug the wires to it? Or can you even un-plug it. I haven’t even gotten a chance to look at it before I ask these questions, but it got a little confusing for me I guess. I will look at it tomorrow morning before work and see how it goes. I will let you know what happens. Thank you very much guys, (and maybe gals, who knows) it’s much appreciated! you guys are great.

Remove the four screws and seperate the silver box from the fuse box. Unplug the two bottom connectors. Don’t remove or unplug the fuse box from the car.

Did you check the headlight switch? Most problems are from aftermarket accessory people leaving the headlight switch unplugged.

@keith, The headlight circuit is not as simple as you might think. They need to come on when the driver turns them on. They come on automatically when it’s dark. They need to flash along with the horn when the anti-theft system is activated. They need to come on high-beam as a Daytime Running Light if required by your locale. They need to come on when the remote entry is activated after dark to illuminate your way. Having all these diverse functions handled by one central unit seems most efficient.

@Nevada_545, I agree on the questionable cost savings, but I think build quality has some issue here. I sure see a lot more bad central timer modules and FCMs than I do similar parts on other makes of cars. Maybe it’s just me?

There hasn’t been any accessories installed on the car since I’ve owned it. There is an OEM car starter that is installed. I don’t know if it was from factory or installed after the car left the factory. I didn’t get a chance to pull the FCM this morning like I wanted to because of downpouring rain but hope to check it out this afternoon if it clears up for 10 minutes. I have not replaced the switch, that will probably be my first thing I replace. It is ordered from Carquest, 3 days away. Not a bad price, only 45 bucks.

Asemaster; High failure rate, cheap parts. These features are common and expected by consumers so building a car on a rental car buget means a $200 module instead of a $500 module.

Tabinak; I think they ordered that switch from your local dealer, the MSRP is $52. With their discount they can buy it for less than $40.