MikeW Posted November 10, 2002 Share Posted November 10, 2002 ALL SORTED NOW -THANKS Lights not working properly and I need to get it sorted quick so any help appreciated. All of the lights ok apart from Rear fog light Headlights-main beam ( but full beam and 'side lights' ok) Checked the fuses -OK No voltage at the rear fog switch Tried changing the headlight switch- no effect Any ideas? MikeW W89 TVV Car no 79 Edited by - MikeW on 12 Nov 2002 22:46:34 Edited by - MikeW on 12 Nov 2002 22:48:02 Link to comment Share on other sites More sharing options...
John Howe Posted November 10, 2002 Share Posted November 10, 2002 Try the multi-pin connectors located inside the nose cone. There is one either side of the radiator on the sub-frame. If this isn't your problem then you need to establish where you have power coming through to... if you have power then check your earth JH Deliveries by Saffron, the 222bhp yellow Sausage delivery machine Link to comment Share on other sites More sharing options...
MikeW Posted November 10, 2002 Author Share Posted November 10, 2002 John, Thanks, I'll have a look at that. I know I have power to the light switch itself. When I bypass the switch it still makes no difference- ie main beam doesn't work ( and fog) but everything else does MikeW W89 TVV Car no 79 Link to comment Share on other sites More sharing options...
John Howe Posted November 10, 2002 Share Posted November 10, 2002 Mike are you able to check that you have power through to the bulb fitting... and don't forget you will need an earth to complete the circuit JH Deliveries by Saffron, the 222bhp yellow Sausage delivery machine Link to comment Share on other sites More sharing options...
MikeW Posted November 10, 2002 Author Share Posted November 10, 2002 I have had a look at the connectors and can't see anything obvious. Problem is ( apart from me not being electrical) is I don't know how the circuit runs. The small lower light in the headlight works and I also have full beam. It is the main headlight that isn't. I assume that it is something do do with the main beam circuit that is the reason for the foglight not working. I'll take the headlight front off and see what I can get to. Thanks Checked and I have 12 v on the connectors in the headlamp.Also the bulbs look ok and they are not open circuit. Does this mean it's some sort of earth problem? Not sure what to do next MikeW W89 TVV Car no 79 Edited by - MikeW on 10 Nov 2002 11:43:07 Link to comment Share on other sites More sharing options...
John Howe Posted November 10, 2002 Share Posted November 10, 2002 Mike if you have power to the bulb (and the bulb is OK), then take a length of wire and run a duplicate earth wire from the bulb to earth (say the negative battery terminal) and the bulb will light up! If it doesn't, then either you don't have power or the bulb is dud. Assuming the bulb lights up, then your problem is the earth and you need to check out why/where the earth is failing. JH Deliveries by Saffron, the 222bhp yellow Sausage delivery machine Link to comment Share on other sites More sharing options...
MikeW Posted November 10, 2002 Author Share Posted November 10, 2002 John, Thanks for your help. I have taken the bulb and put in on the connector so that just the main headlight is connected but to the full beam connector. When I ground this to earth the bulb worked fine ( both of them) With the bulb removed I defintely have 12v BUT when I try and get a reading with the bulb connected I can't get one I REALLY don't understand this. Also it is the same earth for the the full beam which works fine. So I have power to the connector, the bulb works BUT I don't seem to have power once I connect the bulb. I am sure this must be something really simple but I wish I knew what it was. MikeW W89 TVV Car no 79 Link to comment Share on other sites More sharing options...
John Howe Posted November 10, 2002 Share Posted November 10, 2002 Mike, feel for your frustration... since you have proved the circuit works but only when you are holding the bulb in position, rather than when it is sitting in its carrier, could it be that the contact point (in the carrier)for the bulb is not making contact? Easy test, take the other light unit out and swop them over JH Deliveries by Saffron, the 222bhp yellow Sausage delivery machine Link to comment Share on other sites More sharing options...
MikeW Posted November 10, 2002 Author Share Posted November 10, 2002 OK Here goes. 3 pins on the bulb-full beam, main beam and earth. Connect the main beam pin to the full beam supply, earth the the third pin and light works. Connect the main beam pin to its supply ( connected it upside down so the other pins are still exposed) When I then earth the third pin ( same one as above) nothing When I put a voltmeter on I get 12 v if I go directly to the earth in the headlight but nothing if I go to the third earth pin on the bulb This is the same at both sides and with either bulb. If I put the bulbs in properly I can't get a voltage I'm clutching at straws but it 'seems' as if there is something specfic to the main beam circuit that is dropping the volts. I'll try a few more things but otherwise I guess i will need to admit defeat and get it down the garage ☹️ What's really bugging me is I reckon it will be a 2 min fix- never mind MikeW W89 TVV Car no 79 Link to comment Share on other sites More sharing options...
John Howe Posted November 10, 2002 Share Posted November 10, 2002 Mike, just to get things clear in my mind. Yours problem is with both lights, not just one and only one of the two power supplies is live (full beam) and the negative, which is common to both, also works... If the reply is yes, then swop the two output terminals around at the back of the dip switch... if this alternates your problem from dip to full beam then the switch is faulty. If it makes no difference to the current status then you have a break in the loom between the switch and the light. I think there is another multi-connector attached to the diagonal strut in the engine bay, along the induction side, round about where the water bottle lives. Worth checking out, especially if you can pick up the colour coding from the dip switch wiring. You might find that sorting out the headlamp will also fix the fog light. We thought that my wife's Seven had a wiring problem which caused the fog light to only work when the headlamps were dipped. When it went for its MOT she was told it was meant to do that, so dip and fog wiring must be linked in some way! JH Deliveries by Saffron, the 222bhp yellow Sausage delivery machine Link to comment Share on other sites More sharing options...
Johnty Lyons Posted November 10, 2002 Share Posted November 10, 2002 Mike if I read this thread right you have failure of the dip beam cct and the fog light cct. The former will cause the latter since the input to the dip beam fuse is commoned across to the input to the fog fuse so we must presume that you have no power to the dip beam input if as you say both these fuses are AOK. There is a rundemental requirement to understand how Caterham wire these ccts the main light sw powers a battery feed Brown via the lighting relay to the dip sw Blue at this point you manually chose which fuse to feed either the dip fuse Blue/red wit its spur off to the fog fuse or the main beam fuse Blue /white. The head lamp flasher feed is a supplamentary power feed by passing the light sw direct to the main beam cct. It would appear from discussions prior that you have a wire off at the dip sw, or a faulty dip sw, since the light sw and main lighting relay are operational [ your main beam works] Do not be mislead by your 12v reading this is a back feed you can only correctly determine the voltage under load. jj jj N.I. L7C AO. Membership No.3927. Link to comment Share on other sites More sharing options...
MikeW Posted November 10, 2002 Author Share Posted November 10, 2002 Thanks Guys, Just got back from work so will read through what you have said and have another go. I'm not worried about the fog light at the moment because I agree that if I fix the lights this should sort otself out. Don't understand the comment about the 12v only meaningfull under load. Does this mean that although I get a 12v reading from the headlight pin when I have the light switch on ( but without the bulb connected) that I may not actually have the volts I think I have It could explain something in that if I connect the full beam connector of the bulb to the headlight pin that doesn't work either. I did trying swapping the light switch for the heater one and also just shorting out across the pins on the back of the switch and that didn't do anything. Is this something any normal garage could sort out or am I betting taking it to Caterham MikeW W89 TVV Car no 79 Link to comment Share on other sites More sharing options...
Johnty Lyons Posted November 11, 2002 Share Posted November 11, 2002 The light sw is not the problem since by your own admission the side lights and main beam work the fault has to be at the dip sw and yes ignore the 12v at the pin it is a red herring. jj N.I. L7C AO. Membership No.3927. Link to comment Share on other sites More sharing options...
MikeW Posted November 11, 2002 Author Share Posted November 11, 2002 Johnty Confused on your comments re light swtch and dip switch as I only have the one 2 position rocker switch. Full beam and side lights def ok Is there a seperate relay for the dipped headlights 🤔 I don't think the problem is at the lights as they are both identical I've checked and changed the fuses(just to be sure) I've swapped the rocker switch and also bypassed it without a result I'm still unsure what the reading at the light connector is telling me other than with no load and the sitch in the second position I can see 12v but nothing with the bulb connected MikeW W89 TVV Car no 79 Link to comment Share on other sites More sharing options...
Sheds Moderator Posted November 11, 2002 Share Posted November 11, 2002 Don't mither Caterham with it, just take it to any autoelectrician, there's one on every other streetcorner and they fix stuff like this between fagbreaks. 'shame I'm at the wrong end of the country, I like electrical stuff. Nice and logical. Link to comment Share on other sites More sharing options...
Johnty Lyons Posted November 12, 2002 Share Posted November 12, 2002 Now you have me confused, Is it a Caterham with a two positionrocker sw to the right of the steering wheel 1st position brings on the side lights second position brings on the headlights. Below this there are two toggle switches one spring loaded , this is the headlamp flasher the other closer to the wheel toggles between main and dip beam . If tis isn't the case can you tell me how you toggle between main and dip beam? jj N.I. L7C AO. Membership No.3927. Link to comment Share on other sites More sharing options...
MikeW Posted November 12, 2002 Author Share Posted November 12, 2002 Johnty, Sorry I wasn't clear. Things are as you describe but I may have been a bit loose with my descriptions. 2 position rocker switch- At first position side lights come on-no problem Second position- nothing additional happens ie no main headlight-although side lights still on. Spring loaded toggle switch-lights flash -no problem Other toggle switch - full beam comes on- no problem. Main headlight bulbs definitely OK for dipped and full beam Fuses defintely OK I have swapped the rocker switch to no effect Batterdoldsupersport What is remotely logical about electrics 😳 You can't see it, it doesnt end up where you want it and it make my hair go grey 😬 MikeW W89 TVV Car no 79 Link to comment Share on other sites More sharing options...
Johnty Lyons Posted November 12, 2002 Share Posted November 12, 2002 Now were getting somewhere read my prior the problem is not at your rocker sw but at your toggle sw [dip sw] the rocker supplies power to the toggle via the lighting relay if your main beam works then your relay and rocker are aok as you say you swapped the rocker and no change . reasonable there is nougth wrong with it but you either have a wire off at the dip or a faulty dip. jj N.I. L7C AO. Membership No.3927. Link to comment Share on other sites More sharing options...
MikeW Posted November 12, 2002 Author Share Posted November 12, 2002 Johnty Really appreciate your help. I've checked the toggle switch and there are no wires off. Top connector has 2 blue with white Middle 1 blue Bottom blue with red I assume that if I short out between the blue and blue with red then this would bypass the switch and either the dipped headlights would work or it is something else 🤔 MikeW W89 TVV Car no 79 Edited by - MikeW on 12 Nov 2002 20:27:57 Link to comment Share on other sites More sharing options...
MikeW Posted November 12, 2002 Author Share Posted November 12, 2002 Johnty Tried it AND IT WORKS 😬 😬 😬 😬 😬 😬 😬 😬 😬 😬 😬 😬 😬 😬 😬 Big THANKS for your help and to John as well. I knew it would be something simple but didn't know what. You have both( Johnty,John) been a big help and being new to all this fixing it without going to garage is just so satisfying and I couldn't have done it without your help. Hope we get chance to meet some some-beers on me MikeW W89 TVV Car no 79 Edited by - MikeW on 12 Nov 2002 22:45:21 Link to comment Share on other sites More sharing options...
Johnty Lyons Posted November 13, 2002 Share Posted November 13, 2002 My pleasure electrickery is not so difficult and is actually one of the simpler things to fathom I presume when you say sorted that you have a faulty dip toggle the blue is the feed frm the lighting relay the blue /wh the main beam and by deduction and BS the blue/red the dip cct. Well done jj N.I. L7C AO. Membership No.3927. Link to comment Share on other sites More sharing options...
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