Godless Commie

iTrader: (2)

My low beams just went out.

Turned the headlights on, nothing. BUT, the high beam indicator was on.
So I flicked the stalk to high beams. Lights came on, and the indicator was on - well, it should be with high beams.

I pulled the car into the garage and started troubleshooting....

Wiring diagrams are pretty simple:








But, they reveal a glaring brain fart by Mazda...

There is a headlight relay in the system.
You would think that is incorporated in the circuitry to protect the wiring, connections, contacts and whatnot from the relatively high loads a pair of headlights would impart on them.
That is not the case.

All of the wiring, connections, contacts and whatnot are on the ground side of the circuit, after the lights... That means they are subjected to the full wrath of the load the lights generate.

So I pulled the combination switch, and meticulously checked every contact. Nothing. I went ahead and carefully cleaned all contact points with fine sandpaper, anyway.

Checked the fuses, they were discolored... Cleaned the contact points and replaced the fuses, nothing. (I was hoping the corrosion was creating enough resistance to mess things up)

I spent about 4 hours checking the bulbs, bulb connectors (which are new-ish), relay, wiring, and was really frustrated.
It was definitely not the combination switch, or ay of the items I was checking again and again.

Godless Commie

iTrader: (2)

After I checked and cleaned ALL headlight circuit grounds I focused on the headlight wires.
(There are a total of 5 ground points for the headlights. One under the dash, one each under the headlights, one on the right side of the dash on the right wall, and one on the right side of the trunk.. Yes, they are ALL connected.)

There is a RED wire going from the combination switch to the low beam side of the headlights.
It provides ground for the already energized bulbs, and that ground path also turns off the high beam indicator in the instrument cluster.

I checked that wire at several points, and it was behaving as it should, but the low beams were not coming on.

Then I had an epiphany.
There is a rather large connector right under the steering column, and it was pretty much the only connector where this red wire was interrupted.

Unplugging that connector is never easy, and the trick is NOT pulling the locking green slider all the way out. It should be just a hair "in" to take the connector apart. Or, at least that is what worked for me.
Inspecting the terminals inside connector was a horror show:







Those are the male and female terminals of the red wire...
I guess years of service, plus the occasional use of high wattage bulbs had taken their toll on the weakest point in the wiring. No wonder the lights refused to come on.

For reference, here is that red wire:



This is the male side, facing the rear of the car. The red wire in question is on the top right.







This is the side facing towards the front of the car. Red wire is on the top left.


Repairing those terminals would be a nightmare, and pretty doubtful in terms of reliability.
Sourcing a new connector, transferring all the wires to the new plugs was not feasible.
So I decided to think like a heart surgeon: Bypass the damn thing.

Godless Commie

iTrader: (2)

I mean, if the terminals were corroded beyond hope, I could always use bigger, brand new terminals...

So I cut the red wire on both sides of the connector, and proceeded to connect a new one I made...



Solder and heat shrink always does the trick.
If I ever have to unplug that thing in the future, I will not resent spending an extra 10 seconds to unplug the second connector I have added there.



Just taped everything nicely (as nice as it can be working in cramped quarters under the steering wheel).

Yes, I mangled the sliding lock. I said I was frustrated.

Anyway, headlights work just fine now.
I wanted to post everything in detail, hoping it may help someone chasing headlight problems one day.

Joe Perez

iTrader: (8)

It's interesting- I'd never really looked all that closely at the circuit.

The "hi beam" indicator does not indicate that the hi-beams are on. It indicates that the headlight relay is closed, and yet the low-beams are NOT on. It's plain as day looking at the circuit, but I mean, how often does one look at that particular circuit?

DNMakinson

iTrader: (3)

In USA, going to HID headlights on 1999’s; we loose the high beam indicator. In Canada, due to daytime running lights, the circuit is different, so they don’t loose it.