Peter Mears Posted May 3, 2015 Share Posted May 3, 2015 Went to Stoneleigh in the wet today and on arriving the main beam would not switch off.Pulled the switch out and no change, all other lights work normally and the switch does turn on the side lights correctly. Lights dim slightly when the switch is used to attemp to turn off.So its just the dipped main bulb lights that are on constantly none of the back are a problem and main beam switch and flash are fine.The only thing I found was a 7.5 fuse gone but that was affecting the brake lights only and replacing this has made no change to the front dip being on all the time.Any ideas for other things to check, all a bit random really.Cheers Pete Link to comment Share on other sites More sharing options...
SM25T Posted May 3, 2015 Share Posted May 3, 2015 Sounds like the light switch or main/dip switch is fried .... or a wire misconnected. A voltmeter is your friend .... follow the 12V through. Link to comment Share on other sites More sharing options...
Peter Mears Posted May 3, 2015 Author Share Posted May 3, 2015 The lights stay on even when the switch is disconected ! Link to comment Share on other sites More sharing options...
SM25T Posted May 3, 2015 Share Posted May 3, 2015 All switches ? Main light switch .... flasher switch and main/dip switch ? Disconnect all ... and look for the 12V Link to comment Share on other sites More sharing options...
SM25T Posted May 3, 2015 Share Posted May 3, 2015 All switches ? Main light switch .... flasher switch and main/dip switch ? Disconnect all ... and look for the 12V Link to comment Share on other sites More sharing options...
Peter Mears Posted May 3, 2015 Author Share Posted May 3, 2015 Okay with all the switches out the lights are still on , any other earths to check Link to comment Share on other sites More sharing options...
SM25T Posted May 3, 2015 Share Posted May 3, 2015 Well ... you need a 12V supply ..... not to worry about an earth ! Link to comment Share on other sites More sharing options...
Peter Mears Posted May 3, 2015 Author Share Posted May 3, 2015 Have been pointed to an old thread that suggests rear light earth and 12v feeding back so with the fuse having blown on the stop lights will try there. Link to comment Share on other sites More sharing options...
SM25T Posted May 3, 2015 Share Posted May 3, 2015 The brake light fuse is also for the reverse light. It often blows if the split pin on the top of the clutch pedal touches the terminals on the brake light switch. Or if the wires on the reverse light switch touch the tunnel wall. Let us know what you find. Link to comment Share on other sites More sharing options...
F355GTS Posted May 3, 2015 Share Posted May 3, 2015 Main lights use one of the relays, if the switch makes no difference then I'd suspect the relay has failed and is permaneltly connected. Each of the 3? relays are the same so you can use one of the others to prove Link to comment Share on other sites More sharing options...
revilla Posted May 3, 2015 Share Posted May 3, 2015 Just watch out - one of the "relays" is the flasher unit with only 3 pins but otherwise similar looking! Link to comment Share on other sites More sharing options...
Peter Mears Posted May 3, 2015 Author Share Posted May 3, 2015 Next to the relay and fuse box is a small black square unit with a multiplug at the top. What is this and should this be warm to the touch.Relays seem good and main beam switching over fine. Link to comment Share on other sites More sharing options...
F355GTS Posted May 4, 2015 Share Posted May 4, 2015 PeterSounds like the intermittent unit for the wipersre the lightd, if you reconnect the switch and switch to normal headlights do you hear the relay click? or perhaps another way to test if you remove the relay do the lights go off? Link to comment Share on other sites More sharing options...
Peter Mears Posted May 4, 2015 Author Share Posted May 4, 2015 Relays next point of call, ran out of steam with it last night will post how I get on in the daylight. Link to comment Share on other sites More sharing options...
Roger Ford Posted May 4, 2015 Share Posted May 4, 2015 Can we have a more precise definition of the problem? You say :"the main beam would not switch off" but then you say:"its just the dipped main bulb lights that are on constantly"So it's the dip, not the main beam? And can you confirm that when the dip is on, ALL other lights respond normally to controls - are on when switched on, and off when switched off?What about when the main beam is on? Are you able to see whether both main and dip beam filaments are lit, or only the main?The fog light circuit is designed to work only with dip beam on. It seems possible that there's some fault in that that's causing the dip to light up constantly. Try disconnecting the fog light switch and/or the fog light fuse. Link to comment Share on other sites More sharing options...
Peter Mears Posted May 4, 2015 Author Share Posted May 4, 2015 Thismorning I have pulled out and also swopped relays around but the lights still stay on.Another thought is the funny side lights I have. When you turn them on you get the little 5w bulb illuminate, but once the ignition is on and the engine running you get a dimmed headlight as well. This goes to full power when the switch is in position two.I beleive this was a fitment back in 1989 and over the 20 years ive had the car it has always worked fine. Have i missed a relay or somthing that would operate this function.This is starting to get on my nerves now :) Link to comment Share on other sites More sharing options...
F355GTS Posted May 4, 2015 Share Posted May 4, 2015 Ah the old dim dip, pre-cursor of DRL's, I wonder if you've a box managing that perhaps the one you mentioned earleir?. I'd be inclined to cosnder removing the feature :) Link to comment Share on other sites More sharing options...
Peter Mears Posted May 4, 2015 Author Share Posted May 4, 2015 So I've cured the problem by taking out the fuse to the dip beam. But seriously, the fuse for brakes also cures the front but you still can get a glow from the brakes so I believe the big cluster of wires behind the wheel in all the wet need investigation. To be continued............... Link to comment Share on other sites More sharing options...
Peter Mears Posted May 4, 2015 Author Share Posted May 4, 2015 Have now discovered that the fogs work on high beam as well and that the right hand side stop light does not work but the other does. My fuse board does not line up with an owners manual I have so making it difficult, it shows injection fuses and the holes aren't even there on mine.Next call will be the fog lights and as I said all the wire conectors under the wing.Is there another fuse board layout diagram avaliable for the older cars. Thanks for the direction Roger Link to comment Share on other sites More sharing options...
Peter Mears Posted May 5, 2015 Author Share Posted May 5, 2015 Update....Thanks to JK and the correct fuse board diagram I have fixed the problem by removing the fuse called dim/dip. it only affects this function and being that what i think is the unit producing dim/dip was warm to the touch i beleive I have found the problem.Does anyone know if I can get a new unit and should the white plug come out of the top of it. The unit sits to the left of the fuse board is black with and about 2' x 2' and has a fluted heat disperent front.As I do not have intermitant wiper it can only be what I think.Having the wrong fuse board layout had me chasing rad fan switches and all sorts of circuits. Then with a dieing battery things looked even worse. I have seen cars with bad earth problems such as mk3 escorts light up like xmas trees in the past and thought thats where I was, so glad to finaly sort. Now to find a replacment unit if they still exist, thanks for all the input. Pete Link to comment Share on other sites More sharing options...
Mechanical Moz Posted May 5, 2015 Share Posted May 5, 2015 Like F355 said the black box sounds like a combined dim dip relay and resistor. The general consensus with other classics is to bypass it, but I don't know how you would do that in the Caterham installation. Link to comment Share on other sites More sharing options...
Peter Mears Posted May 5, 2015 Author Share Posted May 5, 2015 Just come accross this after searching for the lucas dimdip. Would seem to be a landrover defender part. Says it all really and Ive just spent two days pulling every light out of my car.Time to unplug and forget. It's the Dim-Dip Transformer, it's probably been un-plugged because it's failed. When they fail - Dipped Beam comes on and stays on, even with the master lighting switch in the off position. The Transformer costs a small fortune to replace and, as Dim-Dip is no longer a requirement, I would leave it un-plugged. PRC6336 - Dim-Dip Transformer for Sealed-Beam Headlamps - £149.39 inc VAT Link to comment Share on other sites More sharing options...
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