328 Ignition Key Buzzer Switch Repair | FerrariChat

328 Ignition Key Buzzer Switch Repair

Discussion in 'Technical Q&A' started by carlrose, May 22, 2011.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, Skimlinks, and others.

  1. carlrose

    carlrose Formula Junior

    Nov 25, 2003
    321
    #1 carlrose, May 22, 2011
    Last edited by a moderator: Sep 7, 2017
    Hi everyone,

    Looking for advice on how to repair my 328 ignition switch. Car is 1988.5 model year, and not equipped with ABS system.

    Symptoms included: burning of fuse for interior lights and puff of smoke (!) one day when starting the car. Eventually have tracked this down to an inoperative key buzzer switch, which is separate from the SWF main electrical part of the switch. Apparently this is relatively rare, as I've searched the archives for a few hours and only found a single thread addressing this issue.

    Here is the part denoted with arrows (I've borrowed images from previous threads, please forgive me this trangression, my car is on the lift with the lower dash on the floor):


    My questions are:

    1. How is the 328 tumbler mechanism removed from the lock cylinder? The key currently will turn to all positions appropriately (and the car runs fine). I found previous posts suggesting a button can be pushed in on the side?
    2. How is this switch removed, and is it repairable? The wiring connection in intact (i.e. no wires are broken off). If not, can this switch be purchased separately? (like the other SWF electrical switch), or do I need to start looking for a complete switch? (and any suggestions where to find?)

    I recnognize this is unnecessary to run the car (...and some would even consider this desirable (smile)), but I would really like to have all the factory functions working as intended.

    I've not posted on the board in a few years, glad to see familiar folks. And I'll take pictures and write up this task as well.

    Take care,

    Carl
    Image Unavailable, Please Login
    Image Unavailable, Please Login
    Image Unavailable, Please Login
     
  2. PT 328

    PT 328 F1 Rookie
    Silver Subscribed

    May 1, 2005
    3,955
    HI Carl,

    I am sorry to report that I do not have an answer to your question but I am glad to see you back on F-Chat. I, for one, as well as many others, have benefited from your knowledge and write ups. I hope that someone here can return the favor for your current dilemma.

    Dan
     
  3. carlrose

    carlrose Formula Junior

    Nov 25, 2003
    321
    Thanks Dan!

    I spent earlier today removing the upper steering column to better to able to visualize this switch. It is a small, cylindrical "plunger-type" push-button switch that simply screws (standard thread) into the bottom of the lock cylinder. There is a small flat piece of metal that articulates in the lock to move the plunger down and make connectivity when the ignition is on; when the key is removed, the plunger snaps up.

    Unfortunately I cannot seem to convince my wife's camera to upload all the images I took earlier today. The construction of the switch is such that there are two insulating washers that isolate the plunger from the switch contacts; my washers had disintegrated, causing a short to ground back through the ignition switch. The good news is that I've identified the fault; the challenge now is how to repair.

    As an aside, once realizing the switch simply unthreads, it is easily removable from under the dash (i.e. no need to remove the steering column).

    The switch can be disassembled, and I've jury-rigged mine currently to make it function, but I'm concerned about long-term reliability. I suspect this will be a used-item-only part, so will start calling around tommorrow morning.

    Does anyone on the board recognize this part as cross-referencing to another make/model? Anyone have a used one lying around that I could purchase? (cut wires, no wires, no problem - I only need the cylindrical switch or only even the internal parts).

    Have a good night!

    Carl
     
  4. RGigante

    RGigante F1 Rookie
    Owner Project Master

    Nov 1, 2006
    2,874
    Portugal
  5. RGigante

    RGigante F1 Rookie
    Owner Project Master

    Nov 1, 2006
    2,874
    Portugal
    And by the way, I'm one of the guys that have benefited from your knowledge and write ups.
    Thanks!
     
  6. carlrose

    carlrose Formula Junior

    Nov 25, 2003
    321
    #6 carlrose, May 23, 2011
    Last edited by a moderator: Sep 7, 2017
    Thanks Mr. Gigante!

    The link posted is to the SWF electrical contact part of the switch (i.e. key positions I,II,III), and is a BMW part #61312682120 (the exact part with exact markings) for a BMW 2002, and retails in the US for about $100. For some reason these seem to be getting a bit scarce at this time.

    I've attached some pictures of my key buzzer switch, which protrudes vertically straight down from the switch when viewing from the driving position. The small flecks around the switch are the disintegrated insulating washers which allowed it to short circuit.

    Does anyone recognize this? Similar to another make? Have a spare about?

    Best,

    Carl
    Image Unavailable, Please Login
    Image Unavailable, Please Login
     
  7. FasterIsBetter

    FasterIsBetter F1 Veteran

    Jul 22, 2004
    5,844
    NoNJ/Jupiter FL
    Full Name:
    Steve W.
    Carl,

    I'm confused. It looks like the switch unit is made of plastic. So how is it shorting to ground? Was there a covering on the piston itself? Are you sure that the short is not internal to the switch (in other words, you need a new switch)? Since plastic is non-conductive, it would seem that something else is causing the short, not the deteriorated washer. I'm probably missing something obvious, but just curious at this point.
     
  8. carlrose

    carlrose Formula Junior

    Nov 25, 2003
    321
    #8 carlrose, May 24, 2011
    Last edited: May 24, 2011
    Hi Steve,

    Agreed, it actually took me a while to figure out as well.

    The body of the switch is plastic, with a metal plunger rod. I don't have any images of the switch internals, but basically the design is a ~1mm diameter metal plunger with a "U-shaped" contact that, when depressed, contacts two spade terminals to establish continuity across the switch. A counterspring breaks the continuity at rest. However, the internal plunger is made of metal, and is electrically "isolated" from the U-shaped piece, such that the plunger is not intended to be an active part of the circuit.

    Unfortunately my insulating washers (thin plastic pieces about 3mm diameter) distintegrated with time, and allowed the plunger to become part of the circuit...immediately shorting to ground through the body of the ignition switch and blowing the interior lights fuse. I surmise that one of the washers originally had a collar to surround the plunger shaft, so I cannot simply new ones from a sheet of plastic. I've thought about trying to insulate the plunger, but since it is activated by a metal piece that slides in the ignition switch, I'm not sure how I could accomplish this reliably.

    Turns out this part was never offerred individually, nor was it sold with replacement key switches. I'm still looking at this point.
     
  9. FasterIsBetter

    FasterIsBetter F1 Veteran

    Jul 22, 2004
    5,844
    NoNJ/Jupiter FL
    Full Name:
    Steve W.
    Ah, interesting. So it is an internal short. Makes sense now. And looking at the top picture, it looks like the plastic is discolored. Perhaps you had some heat buildup inside the switch as well, possibly with the short.

    Should be a bit of a PITA to fix this one, it would seem, if the part is not available, and it may be difficult if not impossible to open the old one up without breaking it. Best of luck!! And keep those cards and letters coming.
     
  10. 166&456

    166&456 Formula 3

    Jul 13, 2010
    1,723
    Amsterdam
    #10 166&456, May 24, 2011
    Last edited: May 24, 2011
    It looks remarkably similar to those universal little push switches that you can get for a few $ at Radio Shack or other electronics stores. They're meant for mounting through a front panel but can probably be used here, too. They come in break or make contact configuration and the cheaper ones have for the most part plastic pins so no risk of shorts anymore (though wear could be an issue then). Do look for the max amp rating, though.
     
  11. maurice70

    maurice70 F1 Rookie

    Jan 25, 2004
    4,308
    Sydney
    Full Name:
    maurice T
    #11 maurice70, May 24, 2011
    Last edited: May 24, 2011
    Not that its much help to you but my Euro 328 doesn't have that switch.
     
  12. zoomzoomae

    zoomzoomae Rookie

    Sep 23, 2013
    9
    Can anyone tell me how I can remove the ignition. I broke a key in the lock in the II postion so I cant start nor go back to I. So I removed the ignition par to start it using a screw driver but need to remove the key ignition part to take to someone to fix it.

    So How is the 328 key ignition mechanism removed the dash?

    DO I have open upi everything or is there a particular way to do this.

    Thanks
    Aziz
     

Share This Page