revilla Posted November 20, 2015 Share Posted November 20, 2015 I was just looking at tidying up some of the switches on my dashboard. It's always a good idea to disconnect the battery when working on the electrics but out of curiosity I had a look at the wiring diagram to see what was still live with the ignition switched off. What I noticed in particular was that some of the wiring to the dashboard switches was not only unswitched by completely unprotected by a fuse. I thought this was worth sharing just as a reminder / warning. The diagram below is for a K Series but others are probably similar. The yellow wires are live with the ignition off, but at least are fused. The red wires are connected directly to the battery without any form of short circuit protection. If you accidentally short of any these to ground with a tool while working on things you will in all probability do serious permanent damage to your wiring loom or even start a fire. On the dashboard these include the wiring to the lighting switch, flasher switch, ignition switch and immobiliser LED. Always disconnect the battery when working around potentially live electrics. Always disconnect the negative lead first and reconnect last (if your tools touch the bodywork whilst disconnecting the negative lead nothing will happen and once disconnected there is no return path if your tools touch the bodywork whilst disconnecting the positive lead). Link to comment Share on other sites More sharing options...
Ian B Posted November 20, 2015 Share Posted November 20, 2015 Astounding "design"! Link to comment Share on other sites More sharing options...
OliverSedlacek Posted November 20, 2015 Share Posted November 20, 2015 Standard 'design' for many cars even through the 1980s. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted November 20, 2015 Member Share Posted November 20, 2015 I presume the main lights are done like that for safety reasons.Another approach would be to use a resettable illuminated breaker easily accessible on the dash. And put each of the headlamps on a separate breaker.Jonathan Link to comment Share on other sites More sharing options...
revilla Posted November 20, 2015 Author Share Posted November 20, 2015 @Jonathan,I could see your point if there were no fuse in the circuit, but there is ... it's just "downwind" of the switch wiring. When the headlamps are switched on, the headlights rocker switch activates a relay which switches power through to the main / dipped toggle switch. This sends it either via fuse 8 for main beam or fuse 9 for dipped beam to the lights themselves. I guess this at least means that the main and dipped beam are on different fuses so one won't take the other out.Although it does surprise me that the dash switch wiring is unprotected against shorts, the main reason for my post was not to criticise the design but just to make people aware of the potential consequences of accidentally shorting the lighting switch wiring whilst working on the car. People may expect that the worst that would happen would be that a fuse somewhere would blow. In reality the consequences could be a burnt out loom and a lot of expensive wiring repair needed.Cheers,Andrew Link to comment Share on other sites More sharing options...
DJ. Posted November 21, 2015 Share Posted November 21, 2015 Thanks for the warning My previous Elan Sprint and Westfield only had two fuses, so the Caterham is much better than they were! Link to comment Share on other sites More sharing options...
John Vine Posted November 21, 2015 Share Posted November 21, 2015 Super advice. I've said it before and I'll say it again, Andrew -- you're a star!!JV Link to comment Share on other sites More sharing options...
anthonym Posted August 23, 2018 Share Posted August 23, 2018 Can I have a copy of this diagram please? I've tried copying it but the text is illegible when zoomed in. Very timely, thank you Andrew in 2015 from 2018 :-)Anthony https://www.lotus7.club/sites/default/files/images/Docs/Guides/73414%20Engine%20Harness%20K-seriesR3_4_5.pdf Link to comment Share on other sites More sharing options...
revilla Posted August 23, 2018 Author Share Posted August 23, 2018 Hi Anthony,Which diagram do you want - the complete vehicle loom for K Series, or the one where I have highlighted the unfused wiring?Drop me a BM with your email and I'll mail over whatever you need.Andrew Link to comment Share on other sites More sharing options...
anthonym Posted August 23, 2018 Share Posted August 23, 2018 YHBM - everything please. Link to comment Share on other sites More sharing options...
revilla Posted August 23, 2018 Author Share Posted August 23, 2018 OK I'll try to get everything over to you later tonight or tomorrow. Link to comment Share on other sites More sharing options...
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