Results 1 to 11 of 11

Thread: NA-speedo and factory cruise control?

  1. #1

    Default NA-speedo and factory cruise control?

    My speedometer had been twitching at low speeds and I figured at some point it would need to be changed. That point arrived Sunday as when I made a trip to the store I noticed the speedometer was not functioning at all. So, I have that project added onto to others. This morning on the way to work, I tried to use the cruise cotnrol. Indicator light comes on but c/c will not engage.

    Question is, are the two tied together in some manner that if speedometer isnt working, the cruise wouldnt work?
    Last edited by AlanP1964; 10-11-2010 at 05:51 AM.

  2. #2
    Team Cheap Bastard
    President & Founder
    sammm's Avatar
    Join Date
    Jan 2004
    Location
    NC
    Posts
    6,457

    Default

    Speedo is just a cable from the tranny to the gauges...un-related to the cruise. Cruise works via vacuum, check the hoses for holes and split ends.

  3. #3

    Default

    Thanks. Just thought it was odd that both happened to start up with problems at the same time.

  4. #4

    Default

    Quote Originally Posted by sammm View Post
    Speedo is just a cable from the tranny to the gauges...un-related to the cruise. Cruise works via vacuum, check the hoses for holes and split ends.
    But where does it get the speed signal? I always assumed it came from the speedo, so if the speedo dies then you would lose the cruise control.

    No?
    '94 Black & Black & Tan
    '99 head swap, JR header, TDR intake & header blanket, MegaSquirt, RB hollow bar, Tein Flex, 15x8 6ULs, HD M2 Sport, FM cat, Borla cat-back, black '95M interior, MOMO Zebrano, IL Motorsport console...

    Dyno Days
    8/16/08 (bone stock): 103.1 hp/99.0 lb-ft - Dynojet
    8/23/08 (Borla cat-back): 108.2 hp/104.1 lb-ft - Dynojet
    8/13/11 (more stuff...): 126 hp/116 lb-ft - Mustang dyno

    Roger Moore: the Danny White of James Bonds

  5. #5

    Default

    Quote Originally Posted by trickyrix View Post
    But where does it get the speed signal? I always assumed it came from the speedo, so if the speedo dies then you would lose the cruise control.

    No?
    Found this on that other Miata forum a few minutes ago:

    The speed sensor is part of the speedometer head - The speedometer is mechanical, driven by a cable and contains a speed sensor which reports to the ECU. Yes, it also drives the cruise control

    Can't say I've ever read about a working speedometer which has a malfunctioning speed sensor (usually when you have no speed signal, you have a bad cable) but I suppose anything's possible

    The car in question was reported to be a '96. Mine is a '95. Also, not sure if this info is pertenent to the NA or if this guy pulled this out of his nether region, but it kind of makes a little sense as to my issue.

  6. #6
    Team Cheap Bastard
    President & Founder
    sammm's Avatar
    Join Date
    Jan 2004
    Location
    NC
    Posts
    6,457

    Default

    I never knew they were connected. Thought the speedo was strictly mechanical. Keep us posted.

  7. #7

    Default

    My guess is that if you replace the speedo cable, the cruise will magically spring to life.
    '94 Black & Black & Tan
    '99 head swap, JR header, TDR intake & header blanket, MegaSquirt, RB hollow bar, Tein Flex, 15x8 6ULs, HD M2 Sport, FM cat, Borla cat-back, black '95M interior, MOMO Zebrano, IL Motorsport console...

    Dyno Days
    8/16/08 (bone stock): 103.1 hp/99.0 lb-ft - Dynojet
    8/23/08 (Borla cat-back): 108.2 hp/104.1 lb-ft - Dynojet
    8/13/11 (more stuff...): 126 hp/116 lb-ft - Mustang dyno

    Roger Moore: the Danny White of James Bonds

  8. #8

    Default

    I'm sure I will procrastinate a couple of weeks before changing it but will let you know how it goes. :)

  9. #9

    Default

    When I first got my 01 the speedometer would go on and off, when it went off, the cruise control would kick off too.
    Rob® bent the contact in the Speed Sensor's connector towards the pins in the other end, plugged it back up, and both have worked ever since.
    Obviously the NB's are different from the NA's, but my point is that the systems are connected.
    Last edited by brandonmpace; 10-12-2010 at 11:53 AM. Reason: Corrected spelling of Rob®
    '01 Miata. Silver/Red Stripes. HDHCDD
    '13 Mazda2. Spirited Green.

  10. #10

    Default

    The green-red wire from the cruise control unit in a 1990 goes to the speed sensor in the cluster (2F, labeled "RSW"). Not sure of the color in a 94-97, but it's the same connector on the cluster (see pic - ignore the marker, that's for something else):



    Your speedo stops working (bad cable, stripped gear in teh trans, whatever), your cruise stops working.

    And it's Rob® :P (my last name starts with an R)
    Last edited by Rob®; 10-12-2010 at 07:51 AM.

  11. #11

    Default

    Quote Originally Posted by sammm View Post
    Thought the speedo was strictly mechanical.
    Technically it is: Gear in trans -> cable -> connector on cluster -> speedo gauge.

    The cruise control is not. There is an electronic speed sensor that reads off the back of the gauge. The system works by vacuum, but the ECU gets sent a signal from the electronic sensor. No signal, no cruise. There's a few other electronic sensors here and that that can cause the cruise not to work, but they have no effect on the speedo/odo.

Similar Threads

  1. Cruise Control question
    By wrx74 in forum Miata Tech and Chat
    Replies: 5
    Last Post: 05-14-2009, 09:39 AM
  2. Cruise control issue...
    By channelmaniac in forum Miata Tech and Chat
    Replies: 2
    Last Post: 03-29-2009, 05:28 PM
  3. FS: OEM NB cruise control
    By trickyrix in forum dfwMiata.com Classifieds
    Replies: 9
    Last Post: 02-09-2009, 09:07 PM
  4. Need cruise control switch
    By cam76034 in forum Parts is Parts
    Replies: 3
    Last Post: 09-22-2007, 07:29 AM
  5. Aftermarket cruise control
    By sammm in forum Miata Tech and Chat
    Replies: 9
    Last Post: 03-02-2004, 01:25 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •