Mazda3 headlight/combination switch destroyed!

[rationull]

We're on vacation 1000 miles away from home right now. Took a ferry ride today and left the dog below deck in the car. Big mistake, it turns out. When we got back to the car, in addition to eating a hair clip and some baby wipes, he had bitten off the end of the headlight/fog light/combination switch, leaving it like this:

I was pretty irritated at this, but kind of flipped out when I found out the headlights don't work anymore! I'm going to take it to a Mazda dealer on Monday and hope they can get it fixed -- I think the switch is the problem and I'm hoping they will be able to get one quickly because we were going to leave on Tuesday or Wednesday. Here's what I know:

- Twisting the switch to activate the parking lights or headlights does not work at all.
- Blinkers work. Flashing the high beams works (so the bulbs are OK).
- All fuses related to the headlights are OK. I can't find any mention of a headlight relay in the manual or in the fuse blocks.

The switch has a copper colored kind of ring in it attached to the white (rotating) part with steel colored backing contacts on the black (stationary) part. If I stick a paperclip in at one of several spots while the switch is on, to get the copper part to contact the steel part, I can get the parking lights to come on along with the headlight dash indicator and the "headlights on" chime with the door opened. I have not been able to get the headlights to come on this way.

I'm really confused because I don't see how he could've actually damaged the switch but I'm at a loss if that's not the problem. I'm assuming the switch is supposed to press the copper ring against the backing contacts in particular ways to turn on either the parking lights or the headlights. Even if I could figure out how to get the headlights on this way, though, I don't think it would really get me anything.

Any advice? I can't think of anything I can really do -- AFAICT if the dealer can't get a switch in and fix it we'll have to drive home only in day light which is going to be a chore (at least it's summer). Am I missing anything I should try or check?

 

[BetaBear]

sounds like your switch is bad. The switch usually regulates voltage to turn on specific parts based on voltage. The headlamps probably use a relay for power supply and not directly from the headlamp stalk.

Relay's need a minimum amount of voltage to switch it on. if the voltage supply isn't enough, the coils don't have enough power to pull the internal switch and complete the 12v circuit. Sounds to me like your getting enough power to signal the chime, but not enough to power the relay. I'd test the relay by taking a known good relay and switching it out. It can be for something else like an A/C compressor, as long as its the same relay type.

That is if they run off of a relay.

Best way is to test voltage before the switch and then after the switch on the headlamp circuit, with the stalk turning the lamps on. if you have power before the switch, but none on the wire leaving the switch to turn the headlights on, the switch is your problem and it needs replacing.

Most likely though it's the switch. thank goodness it's not a land rover. those switches go out when you look at them! No chewing involved!

 

[rationull]

I would really think there'd be a relay but I can't find any mention of one in the book or on the diagrams of the fuse blocks. I will check again later.

In any case if it were a relay problem then wouldn't the high beams not work? Or are they generally controlled by a separate relay? I should say that the car has two bulbs per side (one halogen and one projector beam) and both of them come on when you flash the high beams (which I assume is normal) so there's definitely power getting to all the bulbs in that case.

What really ticks me off is of course I have all the tools I'd need along with the car's factory manual -- at home!

 

[rationull]

Just wanted to post to close up this issue. I got a replacement switch at the dealer although in retrospect I probably should've checked junk yards first to save some money. The switch was the problem as evidenced by the fact that the headlights work with the new switch, and that the old one failed testing with a multimeter. Nothing else appears to have been damaged so the dog must've bitten the thing just right to bend something important.

On a related note, I was very impressed by how easily the necessary interior panels came out and how perfectly and tightly they fit back together. I didn't end up breaking anything at all, which is pretty good for me