Announcement

Collapse
No announcement yet.

What's the deal with the E30 turn signal relay?

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    #16
    ok - I'll play then I suppose.

    The flasher relay is a thermatic switch that opens and closes according to a piece of spring steel that heats and cools as current is run through it. I'd presume that when you first put on the indicators, it takes a moment for the spring steel in the switch to heat up (it then opens and closes the circuit as it heats and then cools).

    On most cars the indicators don't come on until the spring steel in the switch has heated as the switch is always open until current is run through it, at which point it closes, then opens, then closes etc... This appears even, although there has actually been a pause BEFORE the first flash.

    I'd assume that in the e30, the switch in the flasher is closed so that as soon as you flick the indicator stick, the indicator comes on - then as the switch heats, it causes the switch to open, then close, then open etc. Hence the slightly longer first flash.

    Presumably BWM did this so that the indicator stalk gave an instant response, rather than having a slight pause before the indicator comes on - this would make the controls potentially seem more responsive than other cars? (Fitting with creating the impression of "the ultimate driving machine") BMW's engineers are renowned for being pedantic, so I'd assume they did think of such things.

    That'd be my best guess without bothering to spend hours pouring over the e30 wiring diagram.
    My e30: OEM+ with M30B35

    Comment


      #17
      Interesting, thanks for laying that out. I also found it curious that on the 2002, the dash light would be on when the signals were off and visa versa. That's a whole separate thing, though. Although, maybe that's how BMW got around the delay issue: if the power goes straight to the corners, it allows the relay time to warm up and slow the light on the dash? Hmm...

      So assumedly, the signal from the stalk passes through the relay to the cluster immediately. I still find it curious that the E30 is the only car I've ever driven or been in that behaves this way. Anyone know of another car that has an initial delay?
      Interested in vintage cars? Ever thought about racing one? Info, photos, videos, and more can be found at www.michaelsvintageracing.com!

      Elva Courier build thread here!

      Comment


        #18
        I'm going to hazard a guess that there's a capacitor that gets charged before the light flashes, and it takes an bit longer the first time because it's completely dead.
        Drive it hard. Maintain it well.


        Convertible Technical & Discussion
        A Topless Memorandum

        Comment


          #19
          Originally posted by mr2peak View Post
          I'm going to hazard a guess that there's a capacitor that gets charged before the light flashes, and it takes an bit longer the first time because it's completely dead.
          Makes sense conceptually. I wonder where the capacitor would be and what purpose it would serve...
          Interested in vintage cars? Ever thought about racing one? Info, photos, videos, and more can be found at www.michaelsvintageracing.com!

          Elva Courier build thread here!

          Comment


            #20
            I think it's more of a Bimetalic switch being used in the relay, but regardless, the intial delay is the metal coming up to temp for lack of a better description.
            1991 325i MT2 Touring (JDM bro)
            2016 Ford Flex
            2011 Audi A3 - wife's other German car

            Comment


              #21
              I got clear front reflectors and yellow leds I guess the leds don't draw enough juice because now my directionals flash fast like a bulb is dead (I don't care)

              /thread diverge

              [IMG]https://cimg4.ibsrv.net/gimg/my350z.com-vbulletin/550x225/80-parkerbsig_5096690e71d912ec1addc4a84e99c374685fc03 8.jpg[/IMG

              Comment


                #22
                No it's because of the change in the circuit design going to LED. To simplify. A light bulb simply is a bidirectional resistive load. An LED is a diode and thus flows voltage a single direction. I'm too lazy to go into the electrical theory that explains it, but it's a design change to the circuit that is causing your issue. It's also why the check panel goes bonkers when you go to LED headlights..


                Sent from my iPhone using Tapatalk
                1991 325i MT2 Touring (JDM bro)
                2016 Ford Flex
                2011 Audi A3 - wife's other German car

                Comment


                  #23
                  I have LED headlights & no check panel issue.

                  Although an led in my "dome light" stopped my George Graves dimmer to not dim (putting an incandescent in restores function)

                  /thread derail?

                  [IMG]https://cimg4.ibsrv.net/gimg/my350z.com-vbulletin/550x225/80-parkerbsig_5096690e71d912ec1addc4a84e99c374685fc03 8.jpg[/IMG

                  Comment

                  Working...
                  X