Problems with clutch safety switch

[wraith1516]

so ive had this problem with css.
when i push in clutch to start the jeep some times it wont start but if i let up on clutch and redepress it it will start have tried disconnecting the fuze( #20iirc) it wont start at all with it disconnected ( 99 wrangler)

 

[Steel City 06]

The fuse is a clutch interlock bypass. With it installed, you should be able to start it regardless of whether or not it is in gear. Without it, you should only be able to start it with the clutch depressed.

Sounds like the switch is bad, or the wiring to it. Could also potentially be unrelated, like an ignition switch or relay.

If you unplug the switch, you should be able to put a multimeter on it and test continuity with it depressed and released. If the continuity does not change, then the switch needs to be replaced. There should be continuity only with the pedal depressed and not while it is released.

You could "hotwire" it by jumping the terminals on the other end of the harness with a piece of wire. That could be a good test. You don't want to do that for more than is necessary to test though.

A bad switch could also cause malfunction of the cruise control.

 

[wraith1516]

dont know how to use multi meter and it is a real jeep (no cruise control ) but thankyou for a starting point

 

[Steel City 06]

I recommend picking up a multimeter. It is a very useful tool for evaluating electrical issues, both automotive and household. I personally own and use this one:
https://www.amazon.com/dp/B019CY4FB4/?tag=wranglerorg-20

I like it because it also has a clamp meter for measuring amperage.

Basically you only need one for this job that tells you the resistance in ohms. Stick the leads into the wiring harness for the switch. It should read zero or close to zero with the clutch pedal depressed and infinity or blank when the clutch is released.

 

[wraith1516]

dont know how to use multi meter and it is a real jeep (no cruise control ) but thankyou for a starting point

what i mean by real jeep is im a confirmed control freak and dont like gismos that take control away from me

 

[wraith1516]

which little squiggly line symbol do i set meter on seriously got zapped really good ehen i was younger and NEVER fucked with any thing electric again

 

[Vasq]

Your Jeep is DC voltage which will be the solid line with the dotted line underneith

NOT the squiggly line

 

[wraith1516]

thankyou

 

[Steel City 06]

Use the Ohm meter. It's the setting with the Omega symbol Ω Use this setting to test the switch. Don't hook it up to anything that could supply power or you'll short it out.

The switch will have no voltage or current in it when it is disconnected. So you cannot be shocked.

Regardless, car electronics are very low voltage, and the risk of shock is low. You could literally grab the terminals of the car battery with dry hands and barely feel anything. Now if your hands were wet, it would hurt, but still probably wouldn't kill you.

 

[wraith1516]

ill pick up a meter tomorrow and give it a go

 

[Goatman]

Is the switch loose in its mount? Causing it to slop around when the clutch pedal arm pushes against it? Just tightening it up may be all you need.
But please don't hotwire around it (other than for testing). I routinely leave all my machines in gear. And I still forget to push in the clutch from time to time. It only takes a second to drive over a bike (or a kid) while you react. That switch is one of the few 'nannies' that I am glad is there.

 

[MLcrisis]

I have recently experienced this situation, but it is very intermittent. I saw in the book were you can put the fuse in the bypass slot. I did that but it still didn't start. I then push started it I get it back home. Once home it was starting again so as a test I put the bypass fuse back in to test and it worked, I didn't need to depress the clutch pedal to start it. My question: do I have a CSS switch starting to go bad or do I look to replace something else?

 

[Jim Byrne]

Remove the switch & hook the wires together---your problems will be over---all the older jeeps didn't have this switch and were trouble free

 

[Steel City 06]

Remove the switch & hook the wires together---your problems will be over---all the older jeeps didn't have this switch and were trouble free

The clutch safety switch is also there to turn off the cruise control if the clutch is depressed while the CC is active. Without it, if you forget to turn the CC off, you would press the clutch and send the RPMs to the rev limiter.

 

[MLcrisis]

Remove the switch & hook the wires together---your problems will be over---all the older jeeps didn't have this switch and were trouble free

I don't want to be stranded again, particularly if I'm not in a position to be push started. Are you saying it is most likely the safety switch versus for example the ignition actuator?

 

[Jimmy schiavoni]

so ive had this problem with css.
when i push in clutch to start the jeep some times it wont start but if i let up on clutch and redepress it it will start have tried disconnecting the fuze( #20iirc) it wont start at all with it disconnected ( 99 wrangler)

So my 2004 Jeep seems like it’s the safety clutch switch not working so i followed instructions on putting in fuse in #20 a 20amp it calls for but still no luck Jeep will not crank. Should I try disconnecting clutch switch on clutch pedal if you can ?

 

[TJ Jim]

Now if your hands were wet, it would hurt, but still probably wouldn't kill you.

 

[Jodh]

Not sure what years we're included but they had a recall involving a clutch safety switch

 

[mrblaine]

The clutch safety switch is also there to turn off the cruise control if the clutch is depressed while the CC is active. Without it, if you forget to turn the CC off, you would press the clutch and send the RPMs to the rev limiter.

I realize this is older but I'd still like to know if you are certain about that? Our experiences are different. The PCM will kick CC off if it sees an RPM rise from the torque converter unlocking when a manual PCM is used with an AW-4 swap. That also means there is no clutch, clutch pedal and the CSS is fully bypassed by hooking that connector into the auto version on the kick panel that completes the series NSS circuit.

 

[Steel City 06]

I realize this is older but I'd still like to know if you are certain about that? Our experiences are different. The PCM will kick CC off if it sees an RPM rise from the torque converter unlocking when a manual PCM is used with an AW-4 swap. That also means there is no clutch, clutch pedal and the CSS is fully bypassed by hooking that connector into the auto version on the kick panel that completes the series NSS circuit.

It is called out in the FSM as such.

I don't doubt there is also RPM detection (which could also detect a slipping clutch or a transmission in neutral), but from what I understand the clutch switch is also used in the process control system.

It could be tested without too much trouble. Find a way to decouple the switch, test drive in cruise control, and flip the position of the switch and see if CC cuts out.