headlamp relay control

[alexblack13]

Hi All,
Here is a question for you Auto electical wizards in our midst!

Dash panel is plugged in and working. All earths are good and checked.

Problem.. When I switch on the headlamps (down position) they light
up via both relays which are 'made'. checked following.

Red/black wire to 'safety' micro switch on r/h headlamp pod = OK.
micro switch ................................................................... = OK.
checked for cable fault on both relay switch supply cables from
dip switch ....................................................................... = OK.
Checked relay con's ........................................................ = OK.

Elimination process found that the fault disappeared if I disconnected
the connection for the highbeam warning lamp at the dip switch. This
looked to be supplying an earth to the relays. I then found that
the relays, which have a common red/black cable to the micro switch
connecting the two relays together ( W1 to W1 I think) was causing
both relays to 'make' via the highbeam connection/warning lamp. The
only solution to the problem I can find (the system works normally with
the lamps up remember) is to split the earthing con's to the micro. In
other words I have run (to test) one cable from each W1 contact on
both main and dip relays to a fixed two pole switch. lifting the lamps
makes or switches to ready, both relays. Switching on the headlamps
then produces normal headlamp operation.

Clear as mud? Answers anyone ?? Its got me foxed at the
moment.

[garyeanderson]

Mud is clear if you have a picture so here is one of the S4 wiring diagram of the head lamp relays.


Blue or U comes of the voltage gegulator and give the relays power to feed the lamps

Blue/brown or U/N off the High/low switch enables the Drive relay

Blue/black or U/B off the High/low switch enables the Main relay

Black/Red of B/R grounds the relay with the headlamp pod in the up position, thus disables the relays (open circuit) with the head lamps in the down position. This is to prevent the headlamps being left on while being retracted and killing the battery.

Blue/Red U/R is the +12v output to the Drive head lamp

Blue/White U/W is the +12 voutput to the Main head lamp

If you tie the B/R to ground BOTH relays will always be enabled that should be all if the relays are good.

The input from the hi/low switch is the toggle that enables one relay and not the other. If both are coming on, you either have it mis-wired or the relay is shorted internally so that the feed from the high/low switch doesent matter.

To trouble shoot, try one relay at a time, if you toggle the high/low switchyou should get Drive beam/ nobeam one way, then switch out the U/B for the U/N and the U/W for the U/R. The U and B/R are common to both relays so they do not need to be messed with. with this configuration you should now get main beam no beam. If you get it so each beam works separately than the circuits are good and the relay tested is good. Now do the same test from the start of the paragraph again with the other relay. This will determin if you have 2 GOOD relays.


If you need help on the wiring the relays, codes and diagrams most are here.

http://www.tvrna.com/lucas/lucas-relays-6ra.htm

[alexblack13]

Hi Gary ?...

Done all that, thanks though. I have the diagram also no probs understanding it etc etc.. Still has a fault though.

As per the post... Whats the answer? I know how to make it work right but I should not have to. I am goin to take the feed for the main beam
warning light from the output end of the relay ( Blu/white to headlamp main beam) Easy way to ssort it I think.

Still should not have to though I dont think the wiring as per the dia is right. the feed to the H/B warning lamp is taken from the wrong place. (In my opinion) Autosparks new loom is as the dia and is fine. Has a built in fault though. I think!

[garyeanderson]

Hi Alex

I'm dislexic, U and N/U both come from the voltage regulator and N/U enters the cabin and become N and N/U. N feeds the courtisy light and N/U goes to a 4 way connector that feeds the Light switch and number 1 pole on the ignition switch. The dip switch takes a feed from the Light switch via U/P and toggles between U/N and U/B. U/B and UG are tied together, U/B feeds the relay and U/G feeds the high beem lamp indicator on the dash, it gets the ground there to light the dash lamp and is always grounded. Now if you have the main beam flasher in the circuit on the Main beam, pull off the W/U from the flasher relay and see what happens.

Gary

[alexblack13]

Hi All, / Gary...

Well I have footered with this all day with my mate and sparky the dog. Coleglie says also Blue black wire /Blue green connected at dip sw' is the culprit. Don't connect the highbeam warning lamp cable and all is nomal...Except no high beam indication!
Fix was as I said. I utilised a spare cable in the loom which was destined for the sear screen heater (which I dont have..DHC ) so all is fine. I just connected the high beam lamp to the blue white on the outfeed end of the relay and the problem went away. I see this as a good mod as the warning light is brighter and the relays are as happy as Larry.

Job done. Thanks all....

Alex B

[billwill]

Don't forget to mark your changes on your copy of the wiring diagram.

You WILL forget what you did & without a marked diagram you will be scratching your head about these weird wires in about 10-15 years time/

[alexblack13]

Hi Bill, All....

First thing I did Bill. Been there and done that. Nothing worse than forgetting what you did. You are so right there so thanks for the joggle.

Diagram is moded and a modification number etc with full discription listed in note attached.

Thanks Bud.

Alex B

[brianw]

Hi Alex,

I read your post re the above with a sense of relief. Following exactly in your footsteps, I just spent a couple of days testing my elan lights to try and find out why the dipped beams remain on even when the pods are down.

They have done this for years but, since I was doing some other work on the headlights, I decided I might as well try and fix the problem. My symptoms, wiring etc appear almost identical to yours, except in my case it does not happen on main beam.

I am certainly not an auto electical wizard (in spite of my surname) and so frankly, the problem was driving me mad. After many hours, I eventually traced the fault back to the main beam warning light. Incidentally, in getting to this point I also discovered that this glows faintly even when the lights are set to dipped beam!

I had reached the point of thinking I should just forget it, but will now follow your advice and look to rewire the warning light. Like you, I can only assume that this is a "fault" that exists in most, if not all, elans. If the car is wired as per the wiring diagram, the blue/black and blue/green connection that feeds the warning light will be live whenever the headlight switch is on.

Thanks for getting there ahead of me and confirming the problem. I am just amazed that something like this can come out of the woodwoork all these years after the car went into production.

Brian Wizard.

[neilsjuke]

Check the earth/s on the relays if you put a volt meter on the earth terminal and then to earth you should have 0 volts
Neil

[alexblack13]

Hi Brian/ All,
This certainly had me baffled for a wee while. My lights were the same as yours exactly with a faint glow on the mainbeam lamp on dip with the pods down. Pods up they worked as they should. Its a simple fix .
Have you fitted a new loom? If so there may be a chance there is a wire you can use. There is a black/white cable ment for the rear screen heater which you might be able to use (if you don't have the screen heater that is)

The fix cures it completly...

Alex B.

[brianw]

Hi Neil,

Like Alex I tried everything in tracking this down and I think his analysis of the problem is spot on. There is a reading on the relay earth even when the micro switch is supposed to be off. As I understand it, this voltage is coming from the main beam blue/black cable on the other side of the relay, which in turn is coming from the main beam warning light.

Hi Alex,

I believe a new loom was fitted when the car was restored and it is a dhc, so the black/white may be available. There is a candidate which is closer to the relays and that is a red/black near the washer pump. It should be connected to something called sovv or sovy according to the wiring diagram (any ideas what this is?).

Maybe it is meant to be the servo since the other end of the cable on the diagram goes back to the brake fail light. In my case this cable is unused, I can find no cables attached to the servo and I don't have a brake fail light in the dash.

Anyway, thanks to you both for your replies. I am just pleased to know why the problem was occurring, fixing it will be a bonus.

Brian.

[brianw]

Hi Neil,

Like Alex I tried everything in tracking this down and I think his analysis of the problem is spot on. There is a reading on the relay earth even when the micro switch is supposed to be off. As I understand it, this voltage is coming from the main beam blue/black cable on the other side of the relay, which in turn is coming from the main beam warning light.

Hi Alex,

I believe a new loom was fitted when the car was restored and it is a dhc, so the black/white may be available. There is a candidate which is closer to the relays and that is a red/black near the washer pump. It should be connected to something called sovv or sovy according to the wiring diagram (any ideas what this is?).

Maybe it is meant to be the servo since the other end of the cable on the diagram goes back to the brake fail light. In my case this cable is unused, I can find no cables attached to the servo and I don't have a brake fail light in the dash.

Anyway, thanks to you both for your replies. I am just pleased to know why the problem was occurring, fixing it will be a bonus.

Brian.

[neilsjuke]

Have you fitted new Lucas type relays as some of the far east patt parts will not take the current and the overheating can make the arms in the relay bend and give faults try a 20 amp relay say from maplins etc

[brianw]

Neil/All,

Relays were replaced by Mick Miller (so not rubbish!), when he did the original restoration, but are not Lucas as far as I can tell. Am more than ever convinced it is a wiring fault that allows the relay to run to earth via the main beam warning light.

BTW, I had tried to speak to Sue Miller re this problem before finding this site, but could not get hold of her at the time. Spoke to her this morning re some other issues and it turned out she knew all about this dipped beam problem. Apparently, many of her clients have inadvertently drained their battery in this way.

Looks like this "fault" has been around forever and it does not appear to be the only one. The other job I was doing was to fit the headlamp flasher, which had also been omitted from my car. The flasher would not work at all when wired to the return side of the headlamp relay, as per the wiring diagram. All was fine when rewired to the live feed on the other side of relay

Brian.

[neilsjuke]

Check the earth/s on the relays if you put a volt meter on the earth terminal and then to earth you should have 0 volts
Neil

Have you done this