rdc Posted March 17, 2011 Share Posted March 17, 2011 Before I mess up a couple of expensive switches, I thought I would get a little input. I have the BMW Fog Lamp Switch (61 31 7 689 809) Are these low amp switches...meaning that they are just for wiring inline between a low amp switched power source and the switch side of a relay? It has three wires...purple, black, gray. How do you wire these in? If you have multiple low-amp switches all going to their separate relays (to power different items), can you provide the low-amp power source to the switches from the same low-amp tap? Thanks! rc Link to comment
dirtrider Posted March 18, 2011 Share Posted March 18, 2011 Evening RDC Is that switch the RT-P fog light switch? If so does it have a LED light in the rocker center? I have seen that switch used for a fan control and aux light control both times using a relay. If it’s the switch I’m thinking of the #2 terminal is grounded to make the LED come on with switch on. Don’t hold me to this though, so I advise using an ohmmeter and completely pinning that switch out before using. I guess lacking other info I would definitely use the switch to control a power relay. That will not only protect your expensive switch but will allow higher voltage to your lights. On your question of: “If you have multiple low-amp switches all going to their separate relays (to power different items), can you provide the low-amp power source to the switches from the same low-amp tap? “----- The answer to this question is yes, as long as the power source isn’t FROM one of the relay controlled circuits as that prevents possible sneak circuits. I have a 1200 RTP police wiring diagram but the darn thing is in German even using German word abbreviations on wire colors so a quick look didn’t reveal much. If you don’t get another response on the wire color vs switch function let me know and I will attempt to find that switch on the diagram and somehow translate the circuit. Link to comment
rdc Posted March 18, 2011 Author Share Posted March 18, 2011 Good Evening dirtrider, Yes, they are lighted switches. Just found information that confirms what you said...ground pin 2 for light. I will check it out just to make sure. So, please check my thinking to see if I am creating any sneak circuits: (I think this is going to take some pencil and paper) 1) Relay controlled Centech fuse panel (Centech is grounded to and powered from battery and relay is triggered from low-amp tap from parking light) 2) Four switches powered by same low-amp tap as relay for Centech 3) Same four switches grounded (for led light) to Centech fuse panel 4) Same four switches connecting to switched side of their own respective relays (four different relays running lights, fan, etc. 5) Four relays powered and grounded through Centech fuse panel Does this keep the four switches power sources separate from the relay controlled circuits? What I am wondering here is should I power and ground the four switches from different sources then the Centech fuse panel and it's respective relay? Have I made this confusing enough? (I think my head hurts!) Thanks alot...I really appreciate your input rdc Link to comment
TestPilot Posted March 18, 2011 Share Posted March 18, 2011 Just a note on the BMW fog light switch. The switch actually has two LEDs. One is on any time the switch is receiving power, so you can see the switch in the dark. The second comes on when the switch is turned ON, and the switch lights up brighter. Link to comment
dirtrider Posted March 18, 2011 Share Posted March 18, 2011 Morning RDC Electrical isolation wise what you want to do sounds good but 5 relays total powered from the same parking light feed might be a bit much for the parking light circuit to handle. You could use micro relays for some of the low powered things but even so that is a lot of load on the parking light driver in the ZFE module. 1)-Relay controlled Centech fuse panel (Centech is grounded to and powered from battery and relay is triggered from low-amp tap from parking light)----- This sounds good and is probably the best place to trigger the Centech control relay from. 2) Four switches powered by same low-amp tap as relay for Centech---- This sounds like too much load for the parking light circuit to handle. A better choice would be to power these from another source like the ignition switch controlled side of the Centech. The Centech should give you enough isolation to prevent problems. Just be sure these power taps are on the fused side of the Centech (or externally fuse them) 3) Same four switches grounded (for led light) to Centech fuse panel----- This should work out fine. (see 4 below for possible relay shutdown back EMF) 4) Same four switches connecting to switched side of their own respective relays (four different relays running lights, fan, etc.----- No problem with this as it should work good. If you are going to use these switches a lot you might consider using relays with internal clipping such as a clipping resistor or clipping diode across the pull in coils, or add you own, to prevent switch contact arcing on shut-off and to prevent high voltage back spikes from the relay coil collapse taking out the switch LED. 5) Four relays powered and grounded through Centech fuse panel---- No problems with this. Link to comment
dirtrider Posted March 18, 2011 Share Posted March 18, 2011 A little on relay identification---- Resistors are commonly used for relay clamping in the automotive field as they are not polarity sensitive so won’t pop if a jumper cable is inadvertently hooked up backwards. The down side of using resistors on vehicles with LOTS & LOTS of continually ON relays is extra power usage. Diode usage for automotive relay clamping usage is usually kept to a minimum due to extreme care in pull in coil polarity and possible damage to inadvertent reverse voltage.---- Link to comment
rdc Posted March 18, 2011 Author Share Posted March 18, 2011 Thanks for sending the photo! My Moto-Lights came with a potted Hella Relay...So I checked out other Hella Relays (for my radiator fan) at rallylights.com. They have a relay HL87453 that has a diode. It isn't potted but I think it would be alright if I mounted upright and in a protected area. From what I understand you have to wire the coil in the opposite manner than a relay without the diode. So the diode is normally reversed bias and only conducts to eliminate reverse spike when coil collapses. So, relay with diode #85 goes to ground and #86 goes to switch? Does that sound right? Eastern Beaver offers a diode wired inline on the ignition switching lead. Would one method be better than another...relay with diode or diode on the switching leads? Oh, what do you mean by having the switches on the fused side of the Centech? Is that the positive side? Again, Thanks... rdc 2006 R1200Rt Link to comment
dirtrider Posted March 18, 2011 Share Posted March 18, 2011 Evening RDC --- From what I understand you have to wire the coil in the opposite manner than a relay without the diode. Only (IF) the diode allows that. You have to pay attention to the polarity of the diode then wire to switch and ground accordingly. I am not familiar with your particular relay so can’t tell you the direction to wire. (this is why I like resistors as they allow wiring either way) --- So the diode is normally reversed bias and only conducts to eliminate reverse spike when coil collapses. Yes, the diode is there to ONLY handle reverse EMF. Those diodes are small so if you wire it to have voltage flow through the diode it will pop the diode when you power the circuit. --- So, relay with diode #85 goes to ground and #86 goes to switch? Does that sound right? Again this depends on the relay and diode polarity. I can't say which way to wire it without seeing the relay's schematic or putting an ohmmeter on it. Just be sure the relay is wired to not flow power through the diode when powered up, it (the diode) should only flow power on coil-collapse reverse voltage spike. --- Eastern Beaver offers a diode wired inline on the ignition switching lead. Would one method be better than another...relay with diode or diode on the switching leads? An inline diode is not the best circuit protection as it has no where to dump the reverse EMF, an inline is much better as a circuit isolator than a spike protector. Also keep in mind that when a diode is placed inline it automatically drops the circuit voltage by .7 volts. ---Oh, what do you mean by having the switches on the fused side of the Centech? Is that the positive side? Just make sure the switches are powered by FUSED power. If wired correctly you should be able to remove one or more of the fuses in the Centech and have the switches go dead. Link to comment
rdc Posted March 20, 2011 Author Share Posted March 20, 2011 Thanks dirtrider...pics very helpful rdc 2006 R1200RT Link to comment
rdc Posted April 1, 2011 Author Share Posted April 1, 2011 Hello Karl, How is your switch wired in? I am working with a schematic that I am beginning to believe might not be representive of my switch. The switch did not come with any diagram. I found several schematics from R1200GS Adventures and the switch was always wired the same. So, I am following that process. I wired it Purple(3) to ground, Black (1) to positive side of relay coil, and Gray (2) to 12volt supply from fuse panel. The LED only lit when the switch was closed. No LED when the switch was open. That was last night, now, I can't even get the LED to light at all. But, the switch does work. I am not sure how I might have damaged the LED. Maybe doing a continuity test with my digital meter? Before I did the test, I checked with Fluke on the outputs of the meter in continuity test mode...7 volts/1mA...so figured it was safe. Maybe not. I have two more of these switches to add...so I need to figure it out! Thanks, Ron Link to comment
TestPilot Posted April 1, 2011 Share Posted April 1, 2011 Ron, Your connections are correct. I'm puzzled as to why the LEDs do not work. Each LED has its own current limiting resistor built into the switch housing. Don Eilenberger on this forum installed one on his R1200R. You could PM him and he might be able to give you additional pointers. Link to comment
rdc Posted April 1, 2011 Author Share Posted April 1, 2011 Test Pilot, Took plastic cover off switch. There is an obvious place for two LED lights, but mine only has one installed. Well, that solves the mystery why some people report two LEDs and others one. Now, to try and figure out why I have none. As you say, it appears that I have it wired correctly. Thanks for your recommendation... Ron Link to comment
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