Clutch Bypass Fuse (Stopped Working?)

[Oman Jeep]

Hi all - stumped by what is probably a fairly simple one and unfortunately the search is mostly showing me results on how to do the Clutch bypass fuse modification, which I've already done.

I've always had the clutch bypass on the 2001 TJ, on the more recent 2006 TJ noticed it's a bit different because it makes the 4WD light stay on and it's under the hood rather than behind the glove box.

It was working fine and as well as the off road benefits, being able to get the A/C on before you climb in has always been a great benefit in the desert. (Neutral check wiggle before starting is always done). Been running it that way about a year now and always use it that way.

Today had the Alternator changed along with the serpentine belt and pulleys and noticed now that my clutch bypass is no longer working. The 4WD indicator light on the dashboard isn't on permanently like before (but does illuminate when shifting in to 4x4). Jeep starts when pressing the clutch but not when relying on the fuse.

I checked the fuse for any signs of damage and it looks healthy, replaced it with a new 10 amp fuse and that didn't fix it.

Any suggestions on what to try next? Does anyone know how that circuit works or where it goes - maybe something was knocked loose?

I don't see how the Alternator changing out could affect it but I mention it as the timing may be more than just a coincidence. Radio booted up in AM so I'm guessing the battery was disconnected during the change over.


Thanks in advance

 

[Steel City 06]

Does the bypass work in 4Low? Rubicon models automatically bypass the clutch safety switch in 4Low, and the fuse method does not work. Even if you don’t have a Rubicon model, it may be worth trying to see if something somewhere got reset in an odd way

 

[whitrzac]

Leave it out for a few start/drive cycles. The ecu needs to 'reset' itself and it will work after that.
It will stop working again anytime the battery gets low or disconnected.

The FSM wiring diagram is incorect for the 06 too. I haven't found the right one yet.

I just cut the wires at the clutch switch and connected them together.

 

[Steel City 06]

Be aware if you straight up eliminate the clutch safety switch, it may affect the cruise control as well. The safety switch is also used to disable the cruise control if the clutch is inadvertently hit while the cruise control is engaged. Without it if you forget the cruise control is on and stomp the clutch, the RPMs will hit the rev limiter almost immediately.

Not going to blow up your engine or anything if you’re careful, but just something to be aware of

 

[Oman Jeep]

Does the bypass work in 4Low? Rubicon models automatically bypass the clutch safety switch in 4Low, and the fuse method does not work. Even if you don’t have a Rubicon model, it may be worth trying to see if something somewhere got reset in an odd way

It's only a Sport (Rubicons aren't common out here as the 4:1 Low was a bit too much for the dunes) but gave it a try anyway - no - 4-low doesn't make a difference. Thanks

 

[Oman Jeep]

Leave it out for a few start/drive cycles. The ecu needs to 'reset' itself and it will work after that.
It will stop working again anytime the battery gets low or disconnected.

The FSM wiring diagram is incorect for the 06 too. I haven't found the right one yet.

I just cut the wires at the clutch switch and connected them together.

Thanks! This is reassuring! Sounds exactly like what's happened, couldn't for the life of me figure out how the two might be related. Not a whole lot of wires other than headlights near the alternator that might have been bumped

I've taken the fuse out and will daily it for a few days and then try again and report back.

 

[mrblaine]

Hi all - stumped by what is probably a fairly simple one and unfortunately the search is mostly showing me results on how to do the Clutch bypass fuse modification, which I've already done.

I've always had the clutch bypass on the 2001 TJ, on the more recent 2006 TJ noticed it's a bit different because it makes the 4WD light stay on and it's under the hood rather than behind the glove box.

It was working fine and as well as the off road benefits, being able to get the A/C on before you climb in has always been a great benefit in the desert. (Neutral check wiggle before starting is always done). Been running it that way about a year now and always use it that way.

Today had the Alternator changed along with the serpentine belt and pulleys and noticed now that my clutch bypass is no longer working. The 4WD indicator light on the dashboard isn't on permanently like before (but does illuminate when shifting in to 4x4). Jeep starts when pressing the clutch but not when relying on the fuse.

I checked the fuse for any signs of damage and it looks healthy, replaced it with a new 10 amp fuse and that didn't fix it.

Any suggestions on what to try next? Does anyone know how that circuit works or where it goes - maybe something was knocked loose?

I don't see how the Alternator changing out could affect it but I mention it as the timing may be more than just a coincidence. Radio booted up in AM so I'm guessing the battery was disconnected during the change over.


Thanks in advance

Hi Laurie

 

[Oman Jeep]

Be aware if you straight up eliminate the clutch safety switch, it may affect the cruise control as well. The safety switch is also used to disable the cruise control if the clutch is inadvertently hit while the cruise control is engaged. Without it if you forget the cruise control is on and stomp the clutch, the RPMs will hit the rev limiter almost immediately.

Not going to blow up your engine or anything if you’re careful, but just something to be aware of

Very good point. No cruise control on mine yet but have been thinking of adding it.

Maybe instead of simply bridging the connector permanently, you could add a relay in the middle and close it when the key is in the crank position, so it would simulate the clutch being pressed only while trying to start it, but not once it's running. Then you'd get clutchless start and no unnecessary 4wd light on the dash while being cruise control compatible... Could even add an inline switch to disable it when it's going for service or anyone else is driving it for some reason...

Make it a 3 position switch and the third position could disconnect everything and it's an anti-theft feature.

Think I might give this a try at some point....

 

[Oman Jeep]

Hi Laurie

HI Blaine,

Good to see you're still around and active! Hope you are well!

 

[mrblaine]

HI Blaine,

Good to see you're still around and active! Hope you are well!

Very well, thanks.

 

[whitrzac]

Be aware if you straight up eliminate the clutch safety switch, it may affect the cruise control as well. The safety switch is also used to disable the cruise control if the clutch is inadvertently hit while the cruise control is engaged. Without it if you forget the cruise control is on and stomp the clutch, the RPMs will hit the rev limiter almost immediately.

Not going to blow up your engine or anything if you’re careful, but just something to be aware of

No it doesnt. The cruise disables itself after the RPM rises without a change in speed, I don't think I've ever had it rise more than 2-300rpm.

It may be different in older TJs

 

[whitrzac]

Be aware if you straight up eliminate the clutch safety switch, it may affect the cruise control as well. The safety switch is also used to disable the cruise control if the clutch is inadvertently hit while the cruise control is engaged. Without it if you forget the cruise control is on and stomp the clutch, the RPMs will hit the rev limiter almost immediately.

Not going to blow up your engine or anything if you’re careful, but just something to be aware of

No it doesnt. The cruise disables itself after the RPM rises without a change in speed, I don't think I've ever had it rise more than 2-300rpm.

It may be different in older TJs

 

[Steel City 06]

No it doesnt. The cruise disables itself after the RPM rises without a change in speed, I don't think I've ever had it rise more than 2-300rpm.

It may be different in older TJs

At least in the latest models (such as my 2006) the clutch safety switch is a part of the cruise control system. The FSM wiring diagrams show a few connections between the two. I wouldn’t be surprised if there’s a second safety based on engine RPM that prevents it if the clutch begins to slip, though.

If I stomp the clutch while moving, the RPMs drop almost instantly.

 

[whitrzac]

At least in the latest models (such as my 2006) the clutch safety switch is a part of the cruise control system. The FSM wiring diagrams show a few connections between the two. I wouldn’t be surprised if there’s a second safety based on engine RPM that prevents it if the clutch begins to slip, though.

If I stomp the clutch while moving, the RPMs drop almost instantly.

And the wiring diagrams are incorrect. The bypass fuse runs to the ecu and no jumps the clutch switch.
It changes the idle speed/reaction in addition to turning the 4wd light on.

If the clutch switch was actually in the cruise circuit, it wouldnt work with it jumpered/fuse or cut/soldered like mine is.

 

[mrblaine]

No it doesnt. The cruise disables itself after the RPM rises without a change in speed, I don't think I've ever had it rise more than 2-300rpm.

It may be different in older TJs

You are correct and in fact that is one of the main issues with swapping in an AW-4. It kills the cruise any time the torque converter unlocks and there is an RPM rise.

 

[mrblaine]

Hi all - stumped by what is probably a fairly simple one and unfortunately the search is mostly showing me results on how to do the Clutch bypass fuse modification, which I've already done.

I've always had the clutch bypass on the 2001 TJ, on the more recent 2006 TJ noticed it's a bit different because it makes the 4WD light stay on and it's under the hood rather than behind the glove box.

It was working fine and as well as the off road benefits, being able to get the A/C on before you climb in has always been a great benefit in the desert. (Neutral check wiggle before starting is always done). Been running it that way about a year now and always use it that way.

Today had the Alternator changed along with the serpentine belt and pulleys and noticed now that my clutch bypass is no longer working. The 4WD indicator light on the dashboard isn't on permanently like before (but does illuminate when shifting in to 4x4). Jeep starts when pressing the clutch but not when relying on the fuse.

I checked the fuse for any signs of damage and it looks healthy, replaced it with a new 10 amp fuse and that didn't fix it.

Any suggestions on what to try next? Does anyone know how that circuit works or where it goes - maybe something was knocked loose?

I don't see how the Alternator changing out could affect it but I mention it as the timing may be more than just a coincidence. Radio booted up in AM so I'm guessing the battery was disconnected during the change over.


Thanks in advance

With the timing, we suggest looking at all the fuses to make sure they didn't do something stupid when they hooked the alternator and battery back up.

 

[Oman Jeep]

With the timing, we suggest looking at all the fuses to make sure they didn't do something stupid when they hooked the alternator and battery back up.

The clutch specific fuse appears to be fine, and even when replacing it with a brand new one out of a packet of spares it made no difference.

Is there another fused circuit that would feed in to this one and something's failed upstream?

Planning on letting it be without the fuse for a few days to try out whitrzac's suggestion - today was a whole lot of work from home but tomorrow has some errands to run so might be enough for it to settle down again.

 

[mrblaine]

The clutch specific fuse appears to be fine, and even when replacing it with a brand new one out of a packet of spares it made no difference.

Is there another fused circuit that would feed in to this one and something's failed upstream?

Planning on letting it be without the fuse for a few days to try out whitrzac's suggestion - today was a whole lot of work from home but tomorrow has some errands to run so might be enough for it to settle down again.

I fully understood that the clutch bypass circuit fuse was good and replaced. What we are thinking if the PCM reset doesn't help is they arced something with reversed polarity and caused another fuse to have an issue. Or maybe they needed to jump start it and hooked the cables up backwards. Or hit the starter without the negative tightened properly.

 

[Oman Jeep]

I fully understood that the clutch bypass circuit fuse was good and replaced. What we are thinking if the PCM reset doesn't help is they arced something with reversed polarity and caused another fuse to have an issue. Or maybe they needed to jump start it and hooked the cables up backwards. Or hit the starter without the negative tightened properly.

Ok. Will get a multi meter and check continuity on all the fuses to be sure. So far everything else seems to work normally.

Thanks

(Btw: Battery is healthy - alternator was only replaced because the bearings were squeaking. So wouldn't have needed jump starting.)

 

[whitrzac]

I fully understood that the clutch bypass circuit fuse was good and replaced. What we are thinking if the PCM reset doesn't help is they arced something with reversed polarity and caused another fuse to have an issue. Or maybe they needed to jump start it and hooked the cables up backwards. Or hit the starter without the negative tightened properly.

The ECU needs to see a 'normal' no bypass fuse installed condition for awhile after the battery is disconnected or run low. I haven't tested exactly how long it needs to be, but it's more than 1 cold start.

I doubt they fried something.