Guest Posted May 10, 2009 Share Posted May 10, 2009 So I have had rear fog lamp installed for a while on my car. Currently it's wired together with front fogs, which is suboptimal - I'd like to operate front/rear fogs independently. For clean and stealth install I'd like to tap into the rarely used parking light switch on the steering column. I'd like to make it "bi-mode" switch - operates parking lights when ignition is off and operates rear fog when ignition is on. Unfortunatelly I have no clue how to accomplish this. It is not simple because the switch is integral part of the tail/clearance lights even when ignition is on (and lights are on). See attached diagram. When switch is "ON" the lights are fed from the battery. Where the switch is "OFF" it actually connects the lights to a relay that's operated by the stalk switch (and ignition). Help will be appreciated! Link to comment Share on other sites More sharing options...
SVXdc Posted May 10, 2009 Share Posted May 10, 2009 Although it's doable, I recommend not mucking with the parking light switch. Does your dash have any blank panels (where buttons would be for features that your model doesn't have)? It would probably be easier to install a new factory switch there (which you hack to run the rear fog) rather than rewiring the parking light switch. When do you want to be able to use the rear fog? Would it be adequate to have it triggered by the reverse lights (perhaps with a switch in series, so you could kill it when you're backing up during daylight)? Or it could even be a circuit so that the rear fog comes on only while you're in reverse while the headlights are on (and thus while the ignition is on). Link to comment Share on other sites More sharing options...
Guest Posted May 10, 2009 Share Posted May 10, 2009 Rear fog is not used when driven in reverse, but for the traffic behind to see you in fog/heavy rain conditions. There isn't really new factory switch... the only one is VDC button which could be added, but it's a momentary switch that would be a pain to wire. With the parking lights switch - I got an idea how to wire. What would be needed is a relay that switches when it get power from two sources, not just one. Do such things exist? Link to comment Share on other sites More sharing options...
rice_rocket Posted May 10, 2009 Share Posted May 10, 2009 Why don't you use the extra button that's beside the windshield fog light switch/dimmer? Link to comment Share on other sites More sharing options...
Guest Posted May 10, 2009 Share Posted May 10, 2009 Why don't you use the extra button that's beside the windshield fog light switch/dimmer? There are no buttons, just dead buttons. I explain it above. I got JDM button for folding mirrors that I plan to retrofit. The 3rd is for VDC. The problem is these buttons come as one assembly... so you either have one with folding mirros, or one with VDC (and the wiper defroster, of course). It's gonna be super pain to combine them into single 3-button assembly, and then even more pain wiring the momentary VDC button. I thought given the above "hijacking" the parking lights button might be easier. Link to comment Share on other sites More sharing options...
rice_rocket Posted May 10, 2009 Share Posted May 10, 2009 Seeing as we're in Boston and we never use a parking light on only, maybe you should just disconnect the wires to the switch and re-wire for the fog lamps. I have to check, but I believe if you turn your stalk you can get the parking lights on anyways even without the key. That way you don't have to much with the system, and can always revert it back... I didn't know you got the JDM mirrors etc... was talking with Scott yesterday and he was telling us all the cool JDM goodness you were getting Link to comment Share on other sites More sharing options...
Guest Posted May 10, 2009 Share Posted May 10, 2009 Yeah, JDM yo! No, the stalk switch works only when ignition is on. I rarely use parking lights, but I sometimes do, so I want to retain them. Link to comment Share on other sites More sharing options...
Guest Posted May 10, 2009 Share Posted May 10, 2009 Ok, I think I got a solution! What I need is the 5-terminal relay! Wired between MB-32 and the pin 1 at the parking light switch. The relay would be controlled by ignition. When off - then MB-32 to pin 1 is closed - parking light operates normally. When on - then MB-32 to pin 1 is open but the extra circuit is closed - triggering fog lamp relay, only when parking light switch is on. Yee-ha! Link to comment Share on other sites More sharing options...
rice_rocket Posted May 10, 2009 Share Posted May 10, 2009 Put up some pics when you get them working! Link to comment Share on other sites More sharing options...
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