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Clutch Igition Switch

My wife is easy on the clutch pedal. I’m the only other driver and I’m easy on it also. We’ve decided to have her mechanic (at his suggestion) disable the switch. When we sell the car, we’ll enable it again.

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I have heard about cases where a floor mat gets under the clutch and won’t let it be fully depressed. You might try removing the mat if you have one.
I remember the Nash and Studebakers of the 1940s and early 1950s where the starter was engaged by depressing the clutch and then giving an extra push on the pedal to activate the starter. I think the system was abandoned when the manufacturers went to suspended pedals.

Might just be a coincidence, hard to say without doing the voltage measurements. There’s an adjustment specification for that switch in the factory service data. Presumably your shop tech has researched that info and adjusted the switch properly.

From what I can see with the key in Start & clutch pedal depressed there’s several things that have to happen to cause the starter motor to receive the “start” signal on its terminal S (the smaller wire) :

12 volts to a 10 amp fuse (number 49), then to the clutch switch, then to a computer module, “IPDM”. The IPDM then grounds the starter relay (presumably that’s a small under-dash relay) which then connects 12 volts to the “start” terminal on the starter motor. This energizes the starter motor and it cranks the engine. There’s involvement with the CAN bus and body control module also for this all to work correctly, which complicates the diagnosis. Like I say, the first thing I’d do is the voltage measurements at the starter motor. It can’t be expected to crank if it isn’t getting proper signal and power to it.

If you are looking for a guess as something to replace – I don’t recommend this approach, easy to run out of money before running out of guesses, but it is still a common way to try to fix problems, esp for diy’ers. You might just get lucky if you replace the starter motor. That’s a really high current and very powerful DC motor, requires a minimum of 10.5 volts at over 100 amps to turn the engine. If it is on the verge of getting that power, sometimes it will crank, and sometimes it won’t. Temperature has an effect, and any slight increase in circuit resistance will prevent it from working reliably. The two places a starter motor typically develops higher than allowed resistance is its solenoid relay contacts, and it’s armature contacts. A new starter motor presumably wouldn’t have either of those problems.

The sensor can “see” the baby or child is in the car. The controller knows engine off, doors locked and occupant still in car. Could even use other qualifiers such as interior temp and elapsed time before unlocking doors and sounding alarm/horns. Most of this infrastructure is already in luxury cars.

My brother just had a similar problem with a Nissan pickup. Turned out not to be the clutch switch, but corroded battery and ground connections. If the mechanic disconnected the battery each time he replaced the switch, that could “cure” the “clutch switch problem” temporarily.


"NHTSA also told CBS News that although ‘technology-based reminders may prevent some instances, concerns about reliability and establishing a false sense of security lead us to believe eliminating these deaths requires education, vigilance, and personal responsibility. The agency expects to issue an additional product evaluation in the coming months.’ "

Key words: Personal & Responsibility

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Take it to a good mechanic. The switch should not be going out of adjustment after properly-performed replacement. Either your mechanic is missing something that is causing the switch to be impossible to properly install (perhaps the actual problem is in what the switch fastens to), or he’s just installing it wrong.

I wonder if it could be a worn bushing on the pedal causing the pedal to change position relative to the switch versus the other way around.

My first clutch safety switch was my 1990 Mazda Rx7. My switch would work most times if I pushed really hard. My neighbor removed the floor mat and it worked every time. He adjusted the switch which was still working 10 years later.

I had a car where the clutch safety switch worked fine until I replaced the clutch master cylinder with one from AutoZone. Then I had to press the clutch all my might to clear the safety switch, else it would not start.

The simple solution was to bypass the safety switch. It worked fine after that.

In the 15 years I was a school bus driver the procedure for dropping off kids changed. We used to drop off the kids at bus stops and leave.

Then one elementary school principal got the idea that we had to drop every student at their house and see them get inside.

When the other principals found out, we had to do the same for them.

Next, we had to make sure someone was there to receive them or make the kids get back on the bus. This meant we could not do our high school run because we had to take the kids to a day care center and all the parents were notified that was where their children would be if they were not home to receive them.

Now, some parents would make no effort to be home for their kids and felt free to work overtime, go out to eat or do whatever they felt like because it was no longer their problem, they could pick up their children at their leisure.

When I retired, the school district was talking about arranging supper for these kids.

Carried to its ultimate absurdity, this will eventually result in parents dropping off their kids at 3 years old at pre-pre-kindergarten and picking them back up at 18.


Not sure how the discussion got to be about school busses, but things sure have changed in the school bus world apparently. In my Colorado elementary years, the school district wouldn’t even let you take the bus unless you lived more than 2.5 miles away from the school. Wouldn’t you know it, I lived 2.45 miles away, and the bus driver would complain like crazy if I was too late to walk, had no other way to get there, so I took the bus. He told me one day after his usual complaints I could only take the bus during severe winter blizzards … lol …

We walked about half a mile to catch a school bus piloted by a driver the kids called “Frog Lady.” :frog:

The bus was so over-crowded that we’d hold our school books in one hand (pre-backpack era) and grasp a seat back with the other, while standing in the isle. :book:

Frog Lady wasn’t that great at shifting the manual transmission, making smooth starts, or anticipating upcoming stops, etcetera. Bless her heart!

We did the best we could to remain on our feet while traveling a few miles to school and the seated kids (who lived closer to the bus route origin) were very polite in helping pick-up our scattered books!

In winter it became even more interesting while Frog Lady tried to navigate frequently icy roads. :wink: