Guest Posted April 20, 2014 Share Posted April 20, 2014 Hi, My Brake lights have stopped working, both sides, all other lights are working fine. The pedal switch appears to be ok, fuse is ok and I have continuity between the switch wires and the fuse box. So I assume there is fault in the wiring from the fuse box to the back of the car. I was wanting to check the connections on the back of the fuse box but I cannot see how to unbolt the fuse box to check behind. Can any one help? The car is a 2010 SV Roadsport 125 sigma. Cheers Graham Link to comment Share on other sites More sharing options...
Wrightpayne Posted April 20, 2014 Share Posted April 20, 2014 Hi Have you also checked for 12v at various points? Sometimes switches can test ok with a meter but won't carry current - try touching the two wires together at the switch and see if they work. Ian Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted April 20, 2014 Member Share Posted April 20, 2014 I don't know the details of your fuse box. Advice should be along in a minute. Send me a BlatMail if you want a picture of the location and which fuse is which. I think that fuse only supplies the brake lights. In the meantime disconnect the feed to your brake switch, quickly jump 12V onto that terminal from the battery and see if the brake lights then work. If they still don't it isn't a fault in the proper feed including the fuse. Have you or anyone else been near the light units recently? One common problem is bad earths. Can anyone advise whether the brake lights share an earth? Jonathan Edited by - Jonathan Kay on 20 Apr 2014 10:12:37 Link to comment Share on other sites More sharing options...
Paul Deslandes Posted April 20, 2014 Share Posted April 20, 2014 Admittedly pretty unlikely but it's just possible that both the bulbs have gone at the same time. Might be worth checking. According to an earlier wiring diagram (k-series 2001 on), the supply is fed to the switch via fuse 1 which also serves the reversing lights, do they still work? The feed from the switch goes directly to the rear lights, not via the fuse box although it may physically pass close or behind, i.e. there is no other electrical connection. Check that 12V appears at the green/pink wire when you press the brake pedal. Not sure if you have a mechanical switch at the pedal or an hydraulic switch in the brake line. If you don't already have it, the wiring diagram is at the back of the assembly guide here. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted April 20, 2014 Member Share Posted April 20, 2014 I think on current Sigma models it's now fuse "A" with no other circuits. Reversing lights are now on "B". Jonathan Link to comment Share on other sites More sharing options...
Paul Deslandes Posted April 20, 2014 Share Posted April 20, 2014 ah, okay. I wasn't sure whether the loom had changed since 2001. Hardly surprising really. Thanks Jonathan Paul Link to comment Share on other sites More sharing options...
Klunk Posted April 20, 2014 Share Posted April 20, 2014 Edited by - Klunk on 20 Apr 2014 10:33:15 Link to comment Share on other sites More sharing options...
Guest Posted April 20, 2014 Share Posted April 20, 2014 Thanks for all the replies. Both bulbs are fine. Tried bypassing the switch, still no luck. Tried connecting the wires running to the switch straight to a battery, still no joy. Not sure when the lights were last seen working. Only a few miles ago (but last October) a new wiper motor was fitted so am wondering if that work disturbed the wiring to the back of the fuses. Hence why I want to get the fuse box detached. Seems both rear light units have a common earth, and as all other lights ok I assume that is fine. I'm sure I have the correct fuse, at one end and one of the few 7.5 amp ones. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted April 20, 2014 Member Share Posted April 20, 2014 On my picture of a Sigma fuse box there's a 7.5A fuse at each end! The one next to the one you want is for the reversing lights: that should help you find it. Check, clean and jump around those earths once you know you are getting 12V at the lampholder. Jonathan Link to comment Share on other sites More sharing options...
Paul Deslandes Posted April 20, 2014 Share Posted April 20, 2014 are the wires to the rear lights a solid connection all the way through or is there a loom connector somewhere at the back of the car? If anyone has a pdf of the Sigma manual it would be handy to have it available on-line as I haven't found one anywhere. I'd be happy to 'host', copyrights permitting. 'P' is for purple, 'K' is for pink 😳 Link to comment Share on other sites More sharing options...
phil 01 Posted April 20, 2014 Share Posted April 20, 2014 I imagine the circuit is ignition on circuit if so ,ignition on test at your 1st position your testing for voltage, test at switch between switch and to earth, if voltage, 2nd position link switchwire and live feed and test at light between live/switchwire and a good earth if voltage suspect poor earth continuity at light Regards phil Edited by - phil 01 on 20 Apr 2014 14:56:48 Link to comment Share on other sites More sharing options...
ChrisC Posted April 20, 2014 Share Posted April 20, 2014 Working from the earth back through the rear light clusters the connections are as follows Earth to rear light clusters B17 and B13 Bulb GP137 (left) and GP136 (right) join in loom into GP 138 GP 138 in main connector (13 way) to Engine loom From Main connector to Engine Loom GP30 to Brake light switch GP30 From Brake light Switch GP29 to smaller connector back into main loom (6 way connector) From small connector G72 to Fuse A (7.5a) From Fuse A W63 connected into loom to W64 - Fuse B Reverse Light W62 - Ignition Switch W61 - Ignition Switch W60 - Fuse S Ignition Supply Engine W59 - Fuse D Heater W65 - Fuse C Instruments W66 - Fuse E Heated Screen W67 - Fuse K Wiper / Wash W69 - Starter Button Link to comment Share on other sites More sharing options...
ChrisC Posted April 20, 2014 Share Posted April 20, 2014 You have no location, if you are local don't mind having a look. Link to comment Share on other sites More sharing options...
tbird Posted April 20, 2014 Share Posted April 20, 2014 Quoting Paul Deslandes: are the wires to the rear lights a solid connection all the way through or is there a loom connector somewhere at the back of the car? If anyone has a pdf of the Sigma manual it would be handy to have it available on-line as I haven't found one anywhere. I'd be happy to 'host', copyrights permitting. 'P' is for purple, 'K' is for pink 😳 Paul is this the one you are after http://uk.caterhamcars.com/sites/default/files/content/uk/documents/assembly_guide.pdf you may need to be logged in to Caterham site to get to it Tim Link to comment Share on other sites More sharing options...
Stationary M25 Traveller Posted April 21, 2014 Share Posted April 21, 2014 Ref your original post .... on any circuit, the route should be ... fuse (supply) ... switch ....load (ie bulb). Maybe corrosion in the bulbholders. Clean bases of bulbs and check inside holders. Check earth wire in screw terminal (or push on connector on later models ?) Inside light clusters Also check if any earth cables not reconnected to wiper motor bracket after it was disturbed. This is the main earth point. Link to comment Share on other sites More sharing options...
Guest Posted April 21, 2014 Share Posted April 21, 2014 Thanks to all for the interest and advice. Problem now solved.I had the windscreen wiper motor r eplaced last November ,noticed broken,not cut,earth wire very close to eyelet near motor.Then found other broken end ,reconnected result. Graham Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted April 21, 2014 Member Share Posted April 21, 2014 :-) Jonathan Link to comment Share on other sites More sharing options...
Stationary M25 Traveller Posted April 21, 2014 Share Posted April 21, 2014 Good news. Now tell us where you are based ....... you can edit your profile to give us a vague clue Link to comment Share on other sites More sharing options...
Guest Posted May 10, 2014 Share Posted May 10, 2014 I don't check my e mails very often. My location is Hemingby.Horncastle nr. Cadwell Link to comment Share on other sites More sharing options...
Stationary M25 Traveller Posted May 10, 2014 Share Posted May 10, 2014 You can edit your profile in BC to show a rough location. Link to comment Share on other sites More sharing options...
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