Ark Posted June 13, 2004 Share Posted June 13, 2004 Hello Everyone, Probably been asked many times before, but I can't find a thread on it so here goes: I'm trying to do Pete Betts' fog lamp conversion using the two automotive relays as described. However, the only relays appear to have only 4 pins (30, 85, 86, 87). There is a stump of a pin for 87a, but I can't see a way to make use of it...It's not a busted pin, because every single one at halfords was like this. I guess my question is:- is this a second pin for 87, so can I simply hang two wires off 87 using a dual spade connectors, or MUST I get new relays with 5 pins present? Thanks guys, Chris Quote Link to comment Share on other sites More sharing options...
Ark Posted June 14, 2004 Author Share Posted June 14, 2004 OK, me and my low-grade electronics skills! If anyone wants to know, I found the answer in the following document: http://www.installdr.com/TechDocs/999404.pdf Told me pretty much everything I needed to know. I guess I ought to try to understand stuff, before going chopping wires off my loom, huh! Chris Quote Link to comment Share on other sites More sharing options...
Digsy Posted June 14, 2004 Share Posted June 14, 2004 Rushing into a job before you've read up on it, eh? Don't worry - it happens to the best of us Quote Link to comment Share on other sites More sharing options...
Ark Posted June 14, 2004 Author Share Posted June 14, 2004 I thought I had read up properly! I assumed that the relays I had bought were the righth ones though. How I know - never assume anything about anything bought straight off the shelf! OK, new question: Should the relays be mounted inside the car boot, or will they be OK tucked underneath the light cluster? Chris Quote Link to comment Share on other sites More sharing options...
Supra ST Myster Posted June 14, 2004 Share Posted June 14, 2004 My fog mod conversion only uses 1 relay and works perfectly well, Dont get any fault lights up (like what Oxy has on his) and still uses all 4 tail lights as normal, ie tails and brakes, and changes the inside pair to fogs when the switch is on while the outer pair is the tails and brakes and also the centre strip if it works on your car. Comes with full install pics and instructions and everything you need. Quote Link to comment Share on other sites More sharing options...
Ark Posted June 14, 2004 Author Share Posted June 14, 2004 Sounds good. Got a URL? Cheers, Chris Quote Link to comment Share on other sites More sharing options...
Digsy Posted June 14, 2004 Share Posted June 14, 2004 Maybe I'm missing something but could you not do this using a single diode for each light cluster? Quote Link to comment Share on other sites More sharing options...
AeroMatt Posted June 14, 2004 Share Posted June 14, 2004 Logically, using a diode would be ideal but I think diodes can only handle very low power and would burn out very quickly. I had a similar problem when making up some headlights for my old MR2. After lots of messing about, I found the only method that worked was using relays. Matt Quote Link to comment Share on other sites More sharing options...
Digsy Posted June 14, 2004 Share Posted June 14, 2004 Originally posted by AeroMatt Logically, using a diode would be ideal but I think diodes can only handle very low power and would burn out very quickly. I had a similar problem when making up some headlights for my old MR2. After lots of messing about, I found the only method that worked was using relays. Matt It's just a matter of picking the right diode to handle the PIV of 14V (with engine running) and the max forward current (1.75A with engine off). There are some hefty diodes out there. Quote Link to comment Share on other sites More sharing options...
Supra ST Myster Posted June 14, 2004 Share Posted June 14, 2004 Theres been a thread about using diodes before and belive the end result was that they were no good although the theroy is there, relays are more reliable and a safer option. Quote Link to comment Share on other sites More sharing options...
Digsy Posted June 14, 2004 Share Posted June 14, 2004 Well if the proper diode is selected, I can't think what the downside would be. It should last longer than a relay too, being all solid-state. You would lose 0.7V from the inner brake light because of the forward voltage drop across the diode, but that should hardly be noticable, especially with the engine running. If anyone has tried this I'd be interested to know exactly what the problems are. Quote Link to comment Share on other sites More sharing options...
Paul Posted September 5, 2004 Share Posted September 5, 2004 Originally posted by Darren Blake If anyone has tried this I'd be interested to know exactly what the problems are. Darren, NO PROBLEMS AT ALL mate. I've just done this mod today using the diode values you suggested in an earlier thread (think it was you?) I ordered them from Maplins and put two in, one between the inner light brake light wire and another in-line on the fog light wire. They work a treat, twin brake and side lights and when the fogs are on the inner most lights act as fogs with the remaining ones still side/brake. Took a little while doing it neat, solder and heat shrink tubing. Thanks again for the advice on the diodes, just a few pence and some solder Paul Quote Link to comment Share on other sites More sharing options...
Simon K Posted March 14, 2006 Share Posted March 14, 2006 Hi all, HAs anyone got any pics or instructions regarding the diode trick ?? What I need from maplins ?? Cheers SBK Quote Link to comment Share on other sites More sharing options...
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