more headlight woes

richrx · June 27, 2010, 03:16:03 PM

:mad:hi all,

im having headlight issues again, so i thought i\'d post this up, im looking for the headlight switch and indicator switches please, my MOT is on thursday and theyve just given up the ghost...

My second querie is, do the headlight and main beams take there power, or earths etc from the same place as its both these functions that keep failing at the switch, the motors and indicators are both working fine.

Im going to wire up some new earths at least, see if that holds this time...

thanks

richard

clive · June 27, 2010, 03:22:03 PM

Good earths are always going to help with the issues you have going on with headlamps

richrx · June 27, 2010, 03:51:06 PM

i thought i had it sorted already with new live wires, but it seems not

its just frustrating beacuse other than this the rex has been a 100% reliable daily driver

i can handle mechanics easy enough, but electrics :rollin not my thing!

Richard

grinder · June 28, 2010, 11:38:02 AM

what is it doing ( or not doing )

richrx · June 28, 2010, 03:11:44 PM

The sidelights and motors all operate as normal, the lights pop up, but dont illuminate, and the high beams dont work at all. the same symptoms as before, except the motors are working, but thats the 12v i re wired, so im expecting the switches to be burnt out, i just need to trace the problem :Hammer

richard

Prof · June 28, 2010, 04:02:07 PM

The light\'s circuit is on one 30A fuse, and the retractor motors are on another 30A fuse. The relay that controls the retractor motors takes it\'s power from the lights circuit - so this tells us both these fuses are ok.

There are 2 relays for the lights - one switches between high and lo beam, and the other controls lights on and off. The circuit could be interrupted there somewhere. From memory - these 2 relays on my car were over on the left hand side of the row of relays.

What happens if you use the flash - do the lights come on at all ?

If they don\'t then it could be earth to the bulbs themselves, or a dodgy connection on the 3 pin connector on the back of the bulbs. The flash hi beam circuit doesn\'t use either of the relays above - so it\'s a good test to see if the earth is ok and check that connector.

Is it a Jap or UK car ?

grinder · June 28, 2010, 04:02:20 PM

have you tried to get them working by bridging the relays at the front - just to make sure that everything is working as it should

although im sure mine did you what yours is doing , i ended up running 2 wires i think , one to get 12v to the relays and one to get 12v to the switch itself

is that what you have done - or have you just fed one 12v feed

richrx · June 28, 2010, 06:23:16 PM

Quote from: Prof;701698There are 2 relays for the lights - one switches between high and lo beam, and the other controls lights on and off. The circuit could be interrupted there somewhere. From memory - these 2 relays on my car were over on the left hand side of the row of relays.

ye, i remember from the last time

i hate this system!!

Quote from: Prof;701698What happens if you use the flash - do the lights come on at all ?

nope, its the same issue as before(if you remember that thread), theres no response from the lights from any switches.

Quote from: Prof;701698If they don\'t then it could be earth to the bulbs themselves, or a dodgy connection on the 3 pin connector on the back of the bulbs. The flash hi beam circuit doesn\'t use either of the relays above - so it\'s a good test to see if the earth is ok and check that connector.

Is it a Jap or UK car ?

I think it might be the earth causing the switches to \'burn out\'. i wish i could just rewire them all :S

its a uk spec s5 convertible.

Quote from: grinder;701698have you tried to get them working by bridging the relays at the front - just to make sure that everything is working as it should

although im sure mine did you what yours is doing , i ended up running 2 wires i think , one to get 12v to the relays and one to get 12v to the switch itself

is that what you have done - or have you just fed one 12v feed

i can bridge power to the relays and all the lights work as normal, so from the relays to the lights are fine. its definetly the switches that have gone, but i need to find out why!!

the last time this happened i put a feed through to one of the pins on the headlight plug behind the dash, i think it was on the bottom of the two rows, 4th from the right.

i think the cause of the failure will be whatever the full beam and headlights have in common...maybe earths, power or relays...i dont know yet :s

a bit of a splurge of info, i think i covered most things as best i could
:cheers again :Talking1

richard.

pdtaylor18 · June 28, 2010, 08:59:31 PM

I should have a switch and as many relays as you want, perhaps you need to start doing continuity checks between the switch-relay and lights to make sure all the earths are good. Of the top of my head i think the earth points by the airbox and on the opposite side cover things like the headlights/indicators etc.
bad earths there are notorious as they seem to hold the water right where the bolts are.
Also make sure your headlight cables going to the motors are not trapped, i have seen something similar before. if you need the bits then it might have to wait as i am away from home but i can get the wife to get the bits posted. What cured it last time?
the switches themselves are amongst the last thing to go.

papercutout · June 29, 2010, 06:41:39 PM

Do you want a series of diagrams that illustrate how to wire some switches in to get them working until you can fix them properly?

You\'d need: lots of wire. 3 switches (1 x on-off, 1x on-off-on and (I think) an on-on) and some time.

With the diagrams it\'s easy.

richrx · June 30, 2010, 04:09:52 PM

Quote from: pdtaylor18;701778What cured it last time?
the switches themselves are amongst the last thing to go.

last time the headlight motors werent working either, so i ran a new 12v feed, as the old one was only reading 7v, i then replaced the switches and that seemed to cure the problem. However whatever caused the switches to burn out before clearly has done it again, so i\'ll need to try and trace the problem, the only downside being i\'ll only know if its still got the problem when the switched go again :3Confused

Quote from: papercutout;701778Do you want a series of diagrams that illustrate how to wire some switches in to get them working until you can fix them properly?

You\'d need: lots of wire. 3 switches (1 x on-off, 1x on-off-on and (I think) an on-on) and some time.

With the diagrams it\'s easy.
.

what i really want is a loom to cut open and find out where all the wires go etc, then re-wire what ive got! im useless with the diagrams, much preffer looking at what needs done rather than a bit of paper.

Oh Pdtaylor, ive sourced switches for the moment, but your offers appreciated, youve helped me out a few times now with parts!

richard

papercutout · June 30, 2010, 08:44:45 PM

By diagrams I mean I have labelled photo\'s. Makes it easy as pie, trust me! BUT they\'ll skip the standard loom and you\'ll use seperate switches as well as the stock item.

pdtaylor18 · July 01, 2010, 01:16:28 AM

For the sake of the time it takes then its easier to start continuity checks on each of the wires that go from the switch to make sure that they are doing what they should. next i would then check to make sure that you have voltage on each of the wires where you should, a diagram will be needed to check what is +ve or -ve and when. Don\'t forget that some systems use the earth as the switch so its vital to get it right. At least with the headlight system everything will be 12v.

lets face it, what is in the system:

12v from fuse box to light switch
earths
Switch ( you will need to check each position)
headlight flasher sytem inc relay (under the glove box)if you have it.
headlight relay
headlight motors

off course all the +ve and -ve wires coming of each of the components. You will need a fluke of some sort to read out volts/resistance etc, the old bulb on a wire trick will not work here. Even though you replaced wiring its not to say that a headlight motor might be at fault, it could even be the fusebox, water can come in that area via the door hinge area (rubber boot not sealing for the wires) or even a hole in the bulkhead.

Just start from the switch and work forward, however if your switch is blown then you will need to bypass that. I would seriously check all the earths, two are in the engine bay for starters.

grinder · July 01, 2010, 09:40:00 AM

you can remove the switch from the equation by applying 12v feed to the various pins in the switch plug

thats how i found out that the switch was only getting around 9v - which wasnt enough to make everything work

out of interest - where did you run the single 12v feed - was that to the switch or to the relays ?

richrx · July 02, 2010, 05:01:31 PM

Quote from: grinder;702204out of interest - where did you run the single 12v feed - was that to the switch or to the relays ?

I ran the 12v to the switch, bottom row, fourth from the right, from memory.

The thing i had trouble with before was tracing the wires from the back of the switch to the other end of the loom, not sure if i was being too impatient :2Rolleyes

I\'ll hopefully get an hour or two tonight to look at it!

Richard