Clutch switch bypass switch

[Tunes67]

I am not gonna get involved in the wiring of the switch here.. but I can tell you what and how that upper switch on the clutch pedal operates. Its a closed switch from ground to the Cruise Control Module. When you depress the clutch pedal.. that switch opens and signals the cruise control module to disengage the cruise. Apparently the neutral safety switch will perform the same function if the shifter is popped out of gear while the cruise control is engaged. Sorry if this was a bit off topic.. but at least now you know what that 2nd switch is for And I got to thank you guys for having this conversation. When I converted my car from ATX to MTX I was never able to get the cruise control working even after connecting that switch on the clutch pedal to the proper pin out of the CCM. It never occurred to me until reading this thread that the neutral safety switch would do the same thing. So thanks I just have to put the neutral safety switch back into the proper circuit with the CCM and my cruise should finally work

Tunes67

[Nd4SpdSe]

Good, good to know. I didn't know cause in my Mx-3, I could switch gears while in cruise....it's just been too long that I can't remember if I tried it pre-KLZE, but I think I did and it worked.

[PoisonDrop]

That's probably why removing mine had no effect. I don't have cruise!

Anyway, it's not off topic. We were just discussing how no one knew what that switch did...

[Tunes67]

I didn't know cause in my Mx-3, I could switch gears while in cruise....it's just been too long that I can't remember if I tried it pre-KLZE, but I think I did and it worked.

Its possible that the two switches work in tandem in a logic circuit within the CCM. This is speculation on my part.. but a simple logic circuit would state that if the clutch pedal is down then the neutral safety switch wont disengage the cruise. But if the pedal is up and the neutral switch is triggered then the CCM disengages the cruise. Could have a timer circuit as well too that would leave the cruise active for a moment to see if there is a signal from the neutral safety switch to indicate a gear change. Again.. this is complete speculation on my part, especially since my car's wiring is hodge podge at best from the ATM to MTX swap. I did trace that wire from the switch to the CCM via my 92 Body electrical troubleshooting manual. But since I still have the TCU for the ATX still plugged in (it worked so I didnt bother to unplug it) I have found that the cruise control circuits are wired differently between the two transmission types. I am assuming that in ATX cars the TCM acts as the neutral safety switch or that another sensor on the ATX itself gives that input. When I did the swap.. there was no harness plug for the neutral safety switch so I never bothered to wire it in. I just figured that its only purpose was to allow the car to start in neutral, which mine does anyway.. so I attributed this to the TCM still being active. When the weather gets nicer I will investigate this more. It would be nice to have cruise for the summer

Tunes67

[Nd4SpdSe]

Its possible that the two switches work in tandem in a logic circuit within the CCM. This is speculation on my part.. but a simple logic circuit would state that if the clutch pedal is down then the neutral safety switch wont disengage the cruise. But if the pedal is up and the neutral switch is triggered then the CCM disengages the cruise. Could have a timer circuit as well too that would leave the cruise active for a moment to see if there is a signal from the neutral safety switch to indicate a gear change.

It's a good theory but it woudn't work. The ECU has no way to distinguish the difference between a ground switched from the clutch or one from the neutral. The only way would be with using a MUX sytem (like your cruise control switches) where different resistances on different circuits would trigger the ECU to perform seperate functions. If this was the case, it would list a resistance check in any service manual, but it doesn't, and they mention only continuity checkes to ground.

I did trace that wire from the switch to the CCM via my 92 Body electrical troubleshooting manual. But since I still have the TCU for the ATX still plugged in (it worked so I didnt bother to unplug it) I have found that the cruise control circuits are wired differently between the two transmission types. I am assuming that in ATX cars the TCM acts as the neutral safety switch or that another sensor on the ATX itself gives that input. When I did the swap.. there was no harness plug for the neutral safety switch so I never bothered to wire it in. I just figured that its only purpose was to allow the car to start in neutral, which mine does anyway.. so I attributed this to the TCM still being active. When the weather gets nicer I will investigate this more. It would be nice to have cruise for the summer

That's possible, but I've never looked into how the cruise works on an auto, so no idea.

[Tunes67]

The ECU has no way to distinguish the difference between a ground switched from the clutch or one from the neutral

Ok.. the ECU has no way.. but what about the CCM? I havent looked to see where or how the neutral safety switch is wired in.. does it connect only to the ECU and not the CCM? I could scan the diagram(s) (I think they are online anyway) from my BET manual and post it if you think that would help determine this. It is all speculation but I would like to fully understand how it works. Would make untangling the wires that much easier for me when I get to it

Tunes67

[Nd4SpdSe]

Diagram here: http://img163.imageshack.us/img163/390/mx32.jpg" onclick="window.open(this.href);return false;
See top-left corner.

You can see that the CSW & NSW are in parallel, and wired in between the CCM and ECU. The CCM has no way to distinguish the difference any differently than the ECU.

[Tunes67]

Cool thanks man. Dunno why it works the way it does then LOL But thanks for the diagram.. gives me another way to see where the NSS is supposed to be wired in. Cheers

Tunes67

[ckysk8ercky2k]

I am swapping from an automatic to a manual in a 93 mazda mx3 GS and im trying to hook up the clutch switch and need some help. I have the wiring diagram posted below but i am still confused on where the wires go. Does the yellow and brown wire from the pedal go to the cruise control then to the PCM or does the yellow and brown wire go straight to the PCM... and if you have to go to the cruise control can you just splice them together? thanks

[Ryan]

It would have been better to start a new thread. Oh well, too late now.

Which clutch switch are you talking about exactly? there are 2 possibilities. The "clutch switch" goes to cruise, the "starter interlock switch" goes to the ECM. They're both on the clutch pedal, so its kinda confusing.

If you read this thread, you'll understand how it all works.

[ckysk8ercky2k]

i read the whole thread before i posted the last one. and i do understand the switches. its not the starter interlock switch. the brown and yellow wire does go to the cruise control and to my tcm. i just am confused on where the two wires from the switch go. can i splice into my cruise control and be done or do i have to wire it all the way to the ECM. and also can i use the automatic ECM or do i have to switch it with the manual ECM...

[Ryan]

If you read the thread, you'd know the ECM doesn't give a rip about the clutch switch. The ecm only needs the starter interlock. Wire it to the proper spot on the cruise module, and you're done. You can use the auto ECM on the manual trans, you'll just have an extra empty plug on the ECM.

[ckysk8ercky2k]

my bad i didnt realize there were 8 pages to the thread. im kindof new to this. but thanks for the information. it helped.

[ckysk8ercky2k]

im still really confused about where to hook this wire up to. do i just splice into the same color wire on the plug for my cruise control on off buttons? or to the buttons on the steering wheel... a wiring diagram or picture would help if possible..