Saturday, June 23, 2012

How to override the Miata's clutch switch (aka starter interlock switch)

What is a clutch switch aka starter interlock switch you ask?  It is the switch that is attached to the top of the clutch pedal that tells the ECU whether the clutch is depressed.  The stock setup requires that the driver hold the clutch down to start the car - probably for insurance liability reasons.  Don't really need this on a race car.

Why override this?  Sometimes, you want to start the car to check something and it gets annoying crawling in through the roll cage to do so.  For that reason, I had been meaning to override the clutch switch / starter interlock for a long time now.  It also gave me something to do as I had some time to kill. :-)  People smarter than me say that depressing the clutch pedal to start causes wear on the thrust bearings.  I personally don't know if that is true but there you go...  

How do you do this?  It takes about 10 minutes.  It took me about 30 minutes googling around trying to figure out how and 10 minutes to do it once I figured it out.  The easiest way to explain it is probably to post these two pics.  If you have any questions, get in touch.


Good luck.


  1. Hey just a quick question, what size spade connector did you use? Do you have any pictures of them?

  2. Just a regular size spade that I had laying around. It fit so I used it. :) Apologies for the delayed response. Never got an email notification on this.

  3. Cant find this on my miata, can only find the clutch switch. witch was broken, so i fixed it.
    Both before AND after the fix I can start the car with neutral in and the clutch up/out. (i always start the car like that)
    is it just some models of the miata that has the plug that u can jump?

  4. Kevin,

    All of the NA and NB Miatas that I've seen have this switch. There are a couple of different ways of defeating it though. The method above was the easiest for me. Maybe a previous owner of your car changed it in a manner different from that in my blog post.

  5. I am a little confused ,you say use 3 male spade connectors where what would you hook the other two up to
    It appears there are only two female slots in the connector
    Appreciate the clarification

  6. Just FYI, this information is partially incorrect.

    You have correctly identified the plug which must be disconnected and jumpered in order to bypass the starter interlock, however the switch which you have labeled as "starter interlock switch" is not the starter interlock switch, nor the switch to which those wires connect.

    The switch you have indicated is the one which signals the ECU and cruise control module that the clutch pedal has been depressed, for the purpose of disengaging cruise and activating the idle / decel code. This switch actuates when the clutch pedal is depressed only slightly.

    The starter interlock switch is much larger, located on the firewall / floor, and is actuated only when the clutch pedal is depressed fully. It is not visible in these pictures.

    1. Interesting. Thanks for the clarification. I'll look for that switch next time I'm under there.

      It does the job anyway.

  7. Hey man! I know this blog post was written almost 4 years ago, but I just followed your instructions and did the clutch to start bypass on my 1990 1.8 swapped Miata!!


  8. Still trying to locate the wire / plug in you have circled. Mine is a 91 Miata manual trans, and I see a plug in with two wires, both black, but one with a red stripe and the other with a blue stripe. Is this it? thanks

  9. Is the switch in the car or under it?

  10. Thanks to the original poster and Joe Perez for the depictions of the plug and clarifications of what the two switches do. One can readily see the starter interlock switch against the firewall has much heavier gauge wire going to it then the ECU / cruise control switch. I disconnected the plug with the two heavy gauge wires going to it, made a jumper out of 10 gauge stranded wire and my 90 Miata fired right up.