led third brake light relay

Man, I can't believe how much mileage I have gotten over this Rostra post. You guys are way over my head, but I surely enjoy all of the jousting. I did indeed contact Rostra after all of this discussion and I got basically the same reply. Surely, others had contacted them on this. I hooked it up exactly as was published on their site and I blew a fuse every time. i hope I'm not getting everyone all fired up again, I just wanted to use this as a way to say hello to all of you fellas. Right now I just have a regular bulb in parallel with the led array and it's working fine. But I would like to try another way that might be a little more professional and there were definitely a few listed here. Thanks again for all of your help.Think ya' used enough dynamite there, Butch?

So the GUILTY part returns to the scene... I forgot this was all YOUR fault! Just kidding!! I do dislike wasting MY time, but no poster here has done that. It is Rostra that has caused that. (That's subject to my own direct confirmation, but as bbstacker repeated above, it seems almost conclusive...) The "more professional" solution is a resistor in parallel with the LEDs. I doubt that a 12Ω 25W would be required (~equivalent to a 21W bulb) - hopefully something like above 220Ω (and hence 1W or less) would suffice.     But that is where Rostra should be able to supply and answer. If they can't specify what minimum resistance is required to "pull down" their input, I'd wonder who the heck is doing their design and supplying their tech information because they certainly have no clue. As to how a company can remain ignorant of such a long standing problem... Oh well, that's Enron, Mistral, Karpin... Maybe they know the are already out of business? It's probably just a matter of time until Rostra are sued for damage or injury. If it's after I contact them, I reckon I can assure it will be a criminal issue.

The generic cruise's are 70's, if not earlier, technology.  I am almost positive a different company or at least a different division of Rostra builds the data cruise's. I thoroughly enjoyed reading and replying to this thread.

I agree the easiest fix is a resistor as you described oldspark.

I am not one to take the easy route often! Much to my own demise most of the time

Yes but I bet you feel the joy when you think of a solution that works, especially one that no one else has thought of. I just purchased a Rover 75 Tourer 'cause it was big cheap quiet and power everything (Google it, never sold in the US). This was simply put a front wheel drive BMW 5 Series BUT:- Different colour wiring looms, the multifunction module was a US Lear instead of Siemens and it had a crazy keyless entry system where the factory fob deadlocks and has priority unlock. What a joy overcoming this, my old Cliff gives me deadlock on arm, regular lock on run, even finding out how to dump the (7) domelights on alarm lock the original fob (with all of 2metres range) did it through the multifunction module. And yes the heating/AC strays in the position you left it in last when you activate the R/S.

howie ll wrote: Yes but I bet you feel the joy when you think of a solution that works, especially one that no one else has thought of.

 That warrants a new signature...

 

To master and control electricity is perfection. *evil laugh*

Actually I like your signature, but try to explain that to some of the morons on the R/start section while you're trying to explain relays and diodes and their function.

Wake up guys! The led backup lights and remote start thread caused me to review this thread. As stated on this page 2 by me, I stuffed up in my first reply in this thread, namely: Note my mistake in my first reply to bbstacker's thread. I state that Rostra say "do not let the violet wire see ground...". In fact the full line is "LEDs do not let the violet wire see ground...". I have forgotten why the Rostra blew fuses. I'm certain it was a direct shorting of brake circuits etc to GND, but now I wonder if it was (also?) from using spike protected relays with internal diodes and following Rostra's inverted #86 to GND and #85 from the +12V switch. (It must be the other way if relays have internal spike protecting diodes. Their wiring will blow fuses or the internal diode.] Incidentally, chasing this up with Rostra has been on my mind since ... last year..., but, you know... And of course blaming Rostra now depends on what I find, or re-find. Not that I may get to review this issue till, um, next year. ....Or next millennium... Cheers.

Hence why I'm so ANAL about making 86 the POS (+) side of the relay coil. Shame on you whoever did those relay diagrams, excellent tutorial but the terminal 86 and 86 inversion? If ISO states that 86 is POS and EVERY car manufacturer agrees then I'll follow that.

The way I see it, since ALL relays with internal spike protection diodes are Kathode to #86, manufacturers and documenters have no choice but to draw and wire IAW ISO etc - ie, 86 is +ve & 85 is -ve. Deviations to that shall be accompanied by a note to ensure internal-diode relays are NOT used. Many know the objection I have always had to such relays. Instead I prefer to add my own diode when required. In part that's because I question why should a spend extra for a relay or if a particular relay blows. As you wrote recently, manufacturers include spark sensing and other circuitry in choke & fuel pump relays or other relays to make more money. If either part fails, you replace both. (And what better way to fail a circuit than by including it in the relay....?) And adding my own suppression diode means I control polarities - ie, I choose which polarity to wire, and the diode is usually then part of the wiring rather than the relay so that such fuse- and diode-blowing situations can't occur. I suspect manufacturers now agree with me, at least on diode protection. They now seem to be rare and resistors used instead. And I don't think the newer ISO micro relays have a similar polarity convention. Or if the do, they don't have internal diodes. If they do have internal diodes, then that will be a great money spinner - newer vehicle fuseboxes often have one-piece metal rails that connect to either micro relay coil terminal (eg, Delphi) much like my relay wiring. I still think however that the Rostra issue was more than their 85 & 86 transposal. But seeing such errors make me question the abilities of such manufacturers etc. Not that I never knew of that convention until after I started contributing to the12volt. But I had no need to - I would merely follow the relay body diagram (which showed if there was an internal diode). And I never specified dioded relays to others (I'd stress to use plain relays and add external diodes or resistors etc) though I'd never specify pin numbers anyhow since my diagrams etc were generic for any type of relay (they were not the "physical" or "wiring" types as generally used on the12volt).

I spoke too soon re micro relays... I've just returned from the wreckers and have an internal diode micro relay. Form that I assume their convention is #1 is +ve & #2 is negative [with 3 being common (30), 5 NO (87) & 4 NC (87a)]. Maybe I should recheck what I said about their coil terminals being "randomly" hard wired to GND or +12V...?