Anybody ever replace the clutch safety switch?

[Z51JEFF]

I'm having issues with the dreaded no start again so decided it's time fix the damn thing once and for all. I've got an NOS switch so that's not the problem,the problem is getting it out of the car. And I thought getting the CDM controller out of the car was a job,this things got it beat.

[Tony Davila]

I by-passed mine, it has been that way for years. I will fix it correctly in the future and yeah it is up there. You need Pray mantis hands to do it.

[We Gone]

Been looking for a switch for some time now so I have not done the clutch safety switch yet but I just did the CDM, can you say 3 hours but that counts I got it all in the first time and had inadvertently flipped it over (maybe something to do with working upside down). After I was done I thought I was going have to call the wife to drag me out lol. I will say it was well worth it I also had the I-Pod hook up added. Good Luck

[Z51JEFF]

Originally Posted by We Gone

Been looking for a switch for some time now so I have not done the clutch safety switch yet but I just did the CDM, can you say 3 hours but that counts I got it all in the first time and had inadvertently flipped it over (maybe something to do with working upside down). After I was done I thought I was going have to call the wife to drag me out lol. I will say it was well worth it I also had the I-Pod hook up added. Good Luck

The safety switch is pretty much the same deal. I just might by pass it, nobody drives the car but me but don't like the idea of having something that doesn't work. On a positive note I'm starting to think the starter is the cause of the no start issue. The last time the car wouldn't start I could hear the starter relay energizing. If the switch kept the circuit open there shouldn't be any power to the starter relay,correct?

[XfireZ51]

Originally Posted by Tony Davila

I by-passed mine, it has been that way for years. I will fix it correctly in the future and yeah it is up there. You need Pray mantis hands to do it.

Agree w Tony. I did this on my 84 sometime ago. What a PITA. If attempting,I highly recommend removing the driver's seat. When I got Roza Nero I bypassed the switch. I depress the clutch as a matter of habit together with always putting the trans in Neutral.

[Paul Workman]

Originally Posted by Tony Davila

I by-passed mine, it has been that way for years. I will fix it correctly in the future and yeah it is up there. You need Pray mantis hands to do it.

I agree w/ Tony and Dom.

By-passed mine too, after the "dreaded no start" phenomenon occurred (foretold by some hesitations at first, followed by having to pump the clutch pedal, and then nothing I tried would work, short of replacing or by-passing it).

I learned to drive back in the dark ages when there were no clutch interlock switches; learned to always mash the clutch when starting - SOP (except for one time just recently where the hand was quicker than the foot - Ooops!)

By-passing the clutch interlock has the advantage of being able to bump the starter w/o having to push the clutch in first. Not a biggie, but occasionally the need arises in the course of maintenance (and not having someone to assist me). And, when would it be convenient for it to fail on you?

There is an "issue" regarding the clutch interlock switch as it is configured in the 90-92 cars* in that ALL of the starter solenoid current passe through that switch. (This will result in arching and thus damaging the contacts especially when the ignition switch is turn to START before the pedal gets depressed far enough to engage the switch (arching), AND especially when the opposite happens, where the pedal is inadvertently lifted before the START (key) is released.)

If one has a 90-92 with a functioning clutch interlock switch, and wishes to isolate that switch from the relatively high solenoid current, a relay can be installed behind the battery to carry the current load, and the clutch switch is only carrying the comparatively tiny current needed to activate the relay.

The supplemental starter relay mod for the 90-92 ZR-1s



Marc Haibeck has an article on his ZR-1 Specialist website he wrote describing the two starter circuits with important test locations w/ voltages throughout the circuits.

[Z51JEFF]

On second thought my starter might it be the problem here. What I thought was the starter relay energizing was something else. Oh well, a bypass jumper is easier than pulling the plenum.

[RussMcB]

Jeff, is your dreaded no start condition: Cranking but not firing? Or not cranking at all?

[Z51JEFF]

Originally Posted by RussMcB

Jeff, is your dreaded no start condition: Cranking but not firing? Or not cranking at all?

Not cranking. I'm going to replace the starter and bypass the clutch switch.

[Paul Workman]

Well, it's your money... But, IMO that is killing a fly with a sledge hammer!

Besides the clutch switch, the other bugaboo are the contacts and bridging "ring" in the solenoid.

I don't disagree w/ bypassing the clutch interlock, damn things can fail w/o warning, and I can think of lots of places that wouldn't be so convenient. (Besides, it is an unnecessary "nanny" measure when proper starting procedures are followed.)

As for the starter, R&R'ing the solenoid amounts to replacing the two "L" contact posts and using a little emery cloth to clean up the carbon tracing on the bridge ring. Voilah! Good as new for under $15 (got mine on ebay).

Once the clutch switch is by-passed, listen for a "click" at the starter when you roll the ignition key. If no "click" (of the solenoid), then check for voltage at the clutch switch first, and if necessary follow back to the starter relay, etc. (assuming fuses are all good).

From Marc Haibeck's paper...

93-95 MYs



90-92 MYs



FWIW, the solenoid contacts failed on my 90 at ≈ 40k miles, and the clutch switch at 57k miles (as a point of reference).

Good luck!