simon metcalfe Posted August 26, 2011 Share Posted August 26, 2011 Hi, having trouble getting the rear fog light to work - Im pretty sure the switch was faulty so have replaced that but replaced the light unit too just in case. When connecting the new switch i heard one of the fuses blow - a 5a one - also now replaced - but still no joy. There is only one way to connect the switch to the pin connections so I have this correct. However, there are two spade connections on either side of the switch - and 2 wires - a black and a red one which look like they are for these connections - however, I'm sure only one of these was connected to the swich before - If I connect them both now then the switch light (normally to indicate it's on) is permenantly on. Should I be using both these wires? Whatever combination I try the fog light itself won't come on now. Pretty sure the earth on the light unit is ok - cleaned with a wire brush before reconnecting. Any ideas / pointers as to where Im going wrong or what else I can check to get it working please? *confused*Regards Simon. Link to comment Share on other sites More sharing options...
Stationary M25 Traveller Posted August 26, 2011 Share Posted August 26, 2011 Think the lamp only works when headlights are on ? Check mystery wires with a voltmeter to see what they do ! Can look at colours on mine later. Link to comment Share on other sites More sharing options...
simon metcalfe Posted August 26, 2011 Author Share Posted August 26, 2011 thanks - and oh yes, forgot to mention, had the headlights switched on also. Simon. Link to comment Share on other sites More sharing options...
wjblundell Posted August 26, 2011 Share Posted August 26, 2011 Any chance the wiring to the lamp has been nipped and is earthing out. Link to comment Share on other sites More sharing options...
millsn Posted August 26, 2011 Share Posted August 26, 2011 Fog wiring often earths to the back panel. That earth doesn't last long (steel plus ally). Is your number plate light also affected? They often use the same earth. You need to run a proper earth back there should this be the problem 😔 Link to comment Share on other sites More sharing options...
Matthew Willoughby Posted August 27, 2011 Share Posted August 27, 2011 I think the fog light may only work if the headlights are dipped and will not work with them on main beam. Link to comment Share on other sites More sharing options...
Cookie Monster Posted August 27, 2011 Share Posted August 27, 2011 Mine is a bit recalcitrant - I just flick it on & off a good few times & then it's OK Link to comment Share on other sites More sharing options...
Peter Mears Posted August 28, 2011 Share Posted August 28, 2011 Had the same problem and just ran a new earth. Check the earth on the wiper motor (under left dash) as this afected all my gauges and switches. Link to comment Share on other sites More sharing options...
simon metcalfe Posted September 1, 2011 Author Share Posted September 1, 2011 Thanks to all for your advice - got there in the end - it was in fact noting more than a corroded live feed - which naturally was the last thing I checked!!! Link to comment Share on other sites More sharing options...
Klunk Posted September 2, 2011 Share Posted September 2, 2011 Hi Simon , I'm sure you've already worked this out but the two spade connections are connected to the red and black wire. This is to illuminate the switch when dark, so comes on when you turn your side lights on. You should find that when you switch on your fog light, a panel on the top edge of the rocker switch ( normally hidden when the switch is off) becomes illuminated. This is just the switch light shining through top of the switch to tell you the fog light is on. Crude but effective. Hope that helps, Giles Link to comment Share on other sites More sharing options...
Area Representative paul richards Posted September 2, 2011 Area Representative Share Posted September 2, 2011 Quoting Matthew Willoughby: I think the fog light may only work if the headlights are dipped and will not work with them on main beam. *confused* Rear guard light (to give it the proper name) should work on dipped and full headlights. Link to comment Share on other sites More sharing options...
tbird Posted September 2, 2011 Share Posted September 2, 2011 Paul It is now allowed for Rear Guard light to be on with dip and main, but we older folk remember when many cars switched of Rear Guard light when Main beam selected, It may even have legislative in the 70s and 80s. I think the idea was that if conditions were clear enough for Main Beam then rear fog was superflous, some cars even had a latching relay so once rear guard was switched of by main beam selection it could only be switched back on by flicking the guard light switch, might be a good idea today, stop numpties driving with guard light on permanently 😬 Tim Link to comment Share on other sites More sharing options...
Area Representative paul richards Posted September 2, 2011 Area Representative Share Posted September 2, 2011 Quoting tbird: Paul It is now allowed for Rear Guard light to be on with dip and main, but we older folk remember when many cars switched of Rear Guard light when Main beam selected, It may even have legislative in the 70s and 80s. I think the idea was that if conditions were clear enough for Main Beam then rear fog was superflous, some cars even had a latching relay so once rear guard was switched of by main beam selection it could only be switched back on by flicking the guard light switch, might be a good idea today, stop numpties driving with guard light on permanently 😬 Tim Thanks Tim - you live and learn (and I'm officially one of the older folk). Link to comment Share on other sites More sharing options...
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