Right headlight out, left headlight flickers, headlight rela

  • MAZDA 626
Hi, I'm new to this forum, looking to fix a really nasty problem on my 1999 Mazda 626 and I'm way over my head. I don't have money to take this to the shop, but my headlights are out so I can't drive at night, as a musician that ruins everything! ;) (I'm only up at night!)


* right headlight is out

* left headlight flickers

* clicking or buzzing sound coming from the "headlight relay" which is in the main (engine compartment) fuse box

If the car is running you hear a buzzing sound coming from the relay and it flickers really really fast, but if the car is off when you turn on the headlights then it clicks instead of buzzing in that fuse compartment and the headlight flickers about 5-10 times a second in time with the clicking coming from the relay.

I checked the fuses in the main fuse box, and they're all fine. I switched the relay with the horn relay (same type) and the other relay did the same thing, so the relay is ok and it's just getting fed some bad electrocity I thinks. I switched light bulbs and the symptoms remained the same; the lights are not burned out. I also tried unhooking the hazard switch and dimmer from the dash but no effect (a n00b move i'm sure).

At this point, the only things I can see in the Haynes manual's diagrams shows me that it could be a short circuit somewhere in the wiring, (lots of wires to trace unfortunately) or the headlight switch could be bad (mounted on steering column) or maybe the CPU is bad. I don't really know how to test these with my multimeter.

No other systems appear to be affected; other lights work and I can drive the car in the daytime.

I should also mention that I just got done getting a new transmission, and then I took the dash apart and replaced burned out bulbs in the dash and also I rewired a new circuit from the battery through a 30 amp inline fuse and a 10-ga cable through the firewall to a new cigarette lighter receptacle and hard-wired battery chargers for my phones and laptop to that as well. Oh and I installed a new stereo and rewired the speakers. I just pulled out the 30-amp fuse to kill that new cig lighter circuit I had put in and nothing changed, and I'm pretty sure I did that right. Things worked for about a month after all that work I did, and just last night this new issue started.

I'm really over my head. I'm a musician and computer haxx0r and I fix my car when it breaks but I'm kind of a hacker here too and not really sure what I'm doing. I wish I could take this to a shop but I have a feeling it could cost $500 and I'm literally broke, so broke that now I can't go to sit in with some natinoally known musicians tomorrow and the next night because I can't drive and anyway I couldn't pay cover to get into the sessions. So I'm looking for advice to get these headlights working myself! I have plenty of electrical wiring and a multimeter and a soldering iron ;)

can anyone help or point me in the right direction to troubleshoot this? Thanks in advance for your help.

www. Nicole-sherburne. Com
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Monday, May 21st, 2007 AT 9:14 PM

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  • 2 POSTS
Crew Chief at Green Flag Auto's forums suggested I needed to check the grounds. Lesson to be learned's short version: always check the grounds first.

Well, it didn't just ground from the light to the frame. But I could tell I had a ground problem since putting an ohm meter between the ground post on the battery and the ground wires showed 55 ohms of resistance for the right light and 12 ohms on the left. That seemed not good to me, even with my limited experience.

I figured out that the grounds to the headlights are definitely switched. The hot wire is also switched, and determines whether the lights are on at all. Then there is a ground to high beam and a ground to low beam that are switched between to control high versus low, and so I couldn't just ground to the frame.

So I ran heavy gauge speaker wire (best I had since the other wire I had was 22ga) from the high-beam ground on the left light to the high-beam ground on the right, and the same for the low beams. The headlights now work 100% correctly and everything is ok.

I have no idea where those grounds eventually end up, since it goes through the switch on the steering column, so I didn't go to the trouble of making sure the rest of that is ok. If the left headlight's grounds fail then they'll go out again. But I'll burn that bridge when I come to it, the one good ground is handling everything just fine.

I swear I will never forget the ground again :)

Nikki the Invincable
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Tuesday, May 22nd, 2007 AT 2:03 PM

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