Headlights not working

[ianelvar]

My headlights have packed up. Here are the symptoms:

Twisting the control to turn on the side and tails does nothing. The tail lights do not turn on, nor do the sides.

It still does nothing if you turn it to full headlights. Dips/full beam makes no difference.

If you push the button to flip up the lights without them coming on they pop up fine.

If you pull the lever to flash the lights they pop up fine, and light up.

The FOG relay in the front relay box can be heard clicking when the light switch is turned to on.

I\'m _really_ confused.

There are some relays that don\'t seem original that _appear_ to be attached to the loom by the lights. They could be part of the alarm, though.

Could someone tell me if the lights on the FD are supposed to pop up in side and tail mode? While they were working they used to do this, and I don\'t think it seems right.

I\'ve been trauling through the wiring diagrams from wrex racing, but I haven\'t quite got my head round it yet. Anyone?

Cheers guys. :cheers

[ianelvar]

An update on this. I\'ve traced it to a wire between the 15A tail fuse, and the TNS relay in the front fuse box. If the wire is replaced the problem is fixed. The strange add-on relays in the left wing seem to be replicating what the normal relays should do. I think there must be a dodgy connector behind the dash (X-08 or X-04 seem to carry this these signal paths) or part of the loom is damaged running down the wing.

I diagnosed this with nothing more than a multi-meter and a couple of resistors. I have found that the wire in question reads 3K-ohm resistance between the TNS relay and 15A tail fuse in the drivers side footwell. I tested the relay because I coudn\'t hear it clicking. It worked fine when given a clean 12V supply. I tested across the coil terminals in the car - they read 12V when switched on. I loaded it with a resistor, and it would only read 0.5V when on. Obviously some part of the circuit was not carrying any decent amount of current.
Bypassing the siwtch and relay, and connecting a wire from the battery directly to th terminals that the relay would activate made the lights function correctly, which lead me to the belief that it could not possibly be an earthing problem. I then measured the resistance of the wire from 15A tail to TNS relay, and bingo, problem found.

I hope this helps someone in the future. I know electrical problems can be hard to diagnose, and I\'m very thankful I have the skills to do it - No thanks to the crappy education system we now have in this country, I might add!!!

[doddy]

This may be crucial help for me with my dodgy lights.
cheers,
dod

[ianelvar]

No worries. PM me if you\'ve got any questions - I\'ve just taken the car out from under her winter wraps to start work again. Good luck with you wiring, I really hope you don\'t have the same trouble I did, it literally took me days to find it.

[doddy]

Hey mate I can\'t PM yet, probably cos I\'m not a club member yet.
Thing is I don\'t want to join unless I get the car MOT\'d!

First of all my car is a Turbo II but your problem seems very similar to mine:
Lights work fine with 15A ILLUM and/or TURN fuse pulled.  
I think ILLUM is for sidelights and TURN should be for indicators, but with either of those out the indicators don\'t work, which is possibly wrong and maybe points to the kind of dodgy short or corroded wires I\'ve got.

With those fuses in the headlights are stuck on mainbeam like something is touching and bypassing the dimmer relay.

FC and FD fuse boxes are a lot different - is TAIL a fuse for back lights?  How did you do some of this stuff e.g. measuring resistance of the wire from TAIL to TNS?!

Did you have to pull the dash apart or move stuff in the engine bay to get at it?

Since the problem seems related to sidelights and indicators I think I should start by finding the colour codes for wires to those components...

Sheesh!

Gonna ask the board now if that fuse behaviour is right...

[ianelvar]

Hello mate. Joining is well worth it, my membership fee has paid for itself at least 10 times over!
You can email me - ianelvargooglemailcom - if you want to though.
I only took off the steering wheel to make it easier to get into the footwell. I hate taking interior trim apart, so I avoid it like the plague! I take it you\'ve got an FC factory wiring manual in pdf? All my information came the the FD wiring manual, and I just followed the wires all throught the loom. Used a digital multimeter for actual fault finding.
I looked at the manual and found the wires I wanted and their locations in the car. I went right from the lights working through the circuit to the battery. I stripped the tape off the loom at odd places I could get to, located the wire, and simply stuffed the point of the probe through the insulation on the wire. There\'s no need to cut them. I simply measured voltage with respect to the battery -Ve and used a bit of deductive logic. Take your time to work through the diagram in your head and think about what state you expect the circuit to be in while the lights are on. I redraw just the parts of the circuit I\'m interesting in, and it helps get a clear picture in my head.

Do feel free to give me a shout if you\'re getting stuck and/or frustrated.

[DMDRIFTING]

I am suffering the same problems on my fd at the moment also!

Was wondering if anybody knows if the wire that runs from the cabin fuse box (Tail 15a) over the drivers wheels to the front relays (TNS) ?

Thank you in advance if anbody can help

[DMDRIFTING]

Just read again and this part of the loom runs across the drivers wing as stated.

My drivers side tyre has been rubbing occasionally on the inner arch, will check this and the tns relay as soon as.

[doddy]

Mine are fixed now! :>
http://mazdarotaryclub.com/forums/showthread.php?t=32221

Turned out to be the relay under the glove box which is UK specific and puts headlights on real dim, but down, when you turn on sidelights. I unplugged that relay and everything was fine.  Said relay is powered from the 15A Tail fuse, so maybe you should have a look for it?

Actually FDs probably don\'t have that setup since I don\'t think the body has windows under the pop ups?

[DMDRIFTING]

Changed relay problem still there!
Guess I need to source the broken wire?

Car electrics are the devils work argghhh!