Dead Clutch Switch?

[scrubs]

Got going on the harness this week. Decided to check continuity on the switches beforehand and noticed the following on the clutch switch:

1) white button depressed - continuity at connectors with the plastic tab
2) white button not depressed (ie clutch pedal making no contact with it): no continuity in either set of connectors.

I assume this switch is dead (please correct me if I am missing something and noted this on another thread: https://www.rockauto.com/en/moreinfo.php?pk=98320&jsn=3&jsn=3


I have a TKO in the crate, where do people connect the neutral safety switch that is on it?

thanks,

j

[Papa]

I'm not sure what specific switch you have, but on mine, the manual was wrong and I had to swap pins on the clutch safety switch. You want whichever pins provide continuity with the button out. Same as the brakes. I think FFR may have used different switches at different times.

I didn't use the neutral safety switch on my car.

[edwardb]

That's a dual function switch. One pair normally open and the other normally closed when the button is not down. With the button down, the open and closed swaps terminals. If you don't have continuity on either pair when the button isn't down, then sounds like it's defective. They're typically pretty reliable, so make sure you're testing it properly. For the brake light switch and clutch safety switch, they are installed with the button pressed down and the wires for each on the open pair of terminals. When either pedal is pushed down, the button is released and the brake lights and starting circuit, respectively, circuits are closed. With it testing the way you describe, won't work for either. BTW, the kit comes with two of those style switches. Did you receive those?

Not everyone uses the neutral safety switch on the trans. In fact, probably most don't. It's an alternative to the clutch safety switch, meaning the starting circuit won't energize unless the transmission is in neutral. Some also wire them in parallel, so either the clutch down or transmission in neutral will allow a start. In either case, you need a relay because the internal TKO switch isn't designed to carry the current of the starting circuit.

[scrubs]

That's a dual function switch. One pair normally open and the other normally closed when the button is not down. With the button down, the open and closed swaps terminals. If you don't have continuity on either pair when the button isn't down, then sounds like it's defective. They're typically pretty reliable, so make sure you're testing it properly. For the brake light switch and clutch safety switch, they are installed with the button pressed down and the wires for each on the open pair of terminals. When either pedal is pushed down, the button is released and the brake lights and starting circuit, respectively, circuits are closed. With it testing the way you describe, won't work for either. BTW, the kit comes with two of those style switches. Did you receive those?

Not everyone uses the neutral safety switch on the trans. In fact, probably most don't. It's an alternative to the clutch safety switch, meaning the starting circuit won't energize unless the transmission is in neutral. Some also wire them in parallel, so either the clutch down or transmission in neutral will allow a start. In either case, you need a relay because the internal TKO switch isn't designed to carry the current of the starting circuit.


Yes, the brake switch seems to work (I get continuity) when the brake pedal is depressed and the button is not down.

The clutch switch won't go into continuity, in either set of connectors, when the button is not pressed (which would be the safety portion). It is in continuity at one set when pressed, which is not the purpose - I guess the car will start with clutch pedal not depressed.

Sounds like I will get a replacement and zip ti the tranny neutral switch:)

Thanks, Edwardb.

[scrubs]

Well, an update. I removed the switch and tested again on the bench...worked. Guess I was notbgetting a good contact as I tried to hold the 2 multimeter leads and press the clutch with the other hand....lessons....

I do appreciate the feedback.

[Mastertech5]

FYI. Those switches were designed to be dual purpose. Brake light/clutch and/or torque converter lockup release when stepping on the brake. Open circuit on one set of terminals when depressed to release TQ lockup. Yes, the manual is wrong about which set of terminals to use for the clutch switch.
Make sure it is adjusted properly.

[MB750]

I'm a stone's throw away from setting my clutch and brake switches, but there's something I can't wrap my head around...

The clutch switch implies there should be a change of state in the switch when the clutch has disconnected the engine from the rest of the drivetrain (clutch fully pressed down)

But the way the clutch switch is mounted it changes state in the first 10% of the clutch lever sweep. There's still TONS of mechanical contact at that point between engine and trans.

All the clutch switches I've seen in my past are on the other side of the lever, so when it's fully pressed down THAT'S when it changes state.

Am I missing something? Or should I shut-up until I've finished that part of my build?

[Alec]

Alligator clip leads attached to the probes on your multimeter - no more issues with too few hands and a bad contact with your multimeter.

[edwardb]

I'm a stone's throw away from setting my clutch and brake switches, but there's something I can't wrap my head around...

The clutch switch implies there should be a change of state in the switch when the clutch has disconnected the engine from the rest of the drivetrain (clutch fully pressed down)

But the way the clutch switch is mounted it changes state in the first 10% of the clutch lever sweep. There's still TONS of mechanical contact at that point between engine and trans.

All the clutch switches I've seen in my past are on the other side of the lever, so when it's fully pressed down THAT'S when it changes state.

Am I missing something? Or should I shut-up until I've finished that part of my build?

No, you're not missing anything and that's been one of my issues with that setup as well. That's one of the reasons I like the Coyote setup better since the switching action occurs at the bottom of the pedal stroke where the clutch is completely disengaged. The stock setup has been discussed quite a bit on here. It does give some measure of safety because you still have to press the clutch pedal an inch or two so you're reminded that it's required and hopefully at that point you go ahead and push it all the way down. But still not a complete failsafe. Another option is to use the transmission neutral safety switch instead of the clutch pedal. That's 100% safe and some like it because you don't have to be in the seat to start the engine. A surprising number of builders opt to not have any safety switch. Not my choice but it comes up quite a bit.

[David Williamson]

I did have a switch fail and they are a common item that was used for years in GM cars.
David W

[MB750]

No, you're not missing anything and that's been one of my issues with that setup as well. That's one of the reasons I like the Coyote setup better since the switching action occurs at the bottom of the pedal stroke where the clutch is completely disengaged. The stock setup has been discussed quite a bit on here. It does give some measure of safety because you still have to press the clutch pedal an inch or two so you're reminded that it's required and hopefully at that point you go ahead and push it all the way down. But still not a complete failsafe. Another option is to use the transmission neutral safety switch instead of the clutch pedal. That's 100% safe and some like it because you don't have to be in the seat to start the engine. A surprising number of builders opt to not have any safety switch. Not my choice but it comes up quite a bit.

Thanks for confirming. I may make a slight modification to mine in this regard. I'm gonna see what kind of switches I can source, and what room is available around the footbox to make it more logical.

[scrubs]

Alligator clip leads attached to the probes on your multimeter - no more issues with too few hands and a bad contact with your multimeter.

ordered