Clutch Anticipate Switch

[Canyonero]

What function does it serve? I see a lead on my '94 Camaro harness for it, but I don't see anything on the 1227727. Should I bother wiring one in? I believe I will be running $88 when I convert.

The switch itself, will it be open or closed when the clutch is pressed?

[pocket-rocket]

I don't recall if its NO or NC type switch, but one function is to shut off the cruise control when you engage the clutch. I know I have need of replacing the switch in my 92, because the computer barks at me about it, so mine is actually wired to the ECM as well. As far as the 727 and $88, I can't help you, but there should be someone here that can.

[Canyonero]

Oh, that makes sense why the one ECU would have it and the other doesn't. If it's just for cruise then I don't need it. I already have factory cruise that is independent of the ECU.

[IsaacHayes]

Well you still might want it, so that you can wire it to the same circuit that your brake lights are that tell the aftermarket cruise when the brakes are applied, so it kills the cruise. That way it will kill it when you hit the clutch as well... Otherwise it might rev the hell out of the motor when you push in the clutch and forget to turn off the cruise first... lol

[Canyonero]

It's not aftermarket cruise, it's the original Trooper subsystem. Independent of either ECU. Just takes vacuum and has a VSS in the speedometer. Clutch and brake sensors are already in place.

[IsaacHayes]

Ah. Cool.

[SappySE107]

I never ran that switch on my 5 speed grand prix and disabled the ECM telling me about it.

[Canyonero]

So is it just for cruise control or also some other engine function?

[pocket-rocket]

I never ran that switch on my 5 speed grand prix and disabled the ECM telling me about it.

X2 with the 91 anyways. I never disabled it in the 92 since it had it from the factory though. Now that Ben is involved with this thread, maybe he can shed some light on what it does in the 5 speed DOHC code. But then if your ECM doesn't use it, it probably wouldn't know what to make of it in the first place so it might be fine to leave it out as far as the ECM wiring goes.

[SappySE107]

I didn't notice any problems with it disabled and not used at all. Aside from cruise control disable on clutch in, there isn't much for it to do.

[Canyonero]

I did find it in another diagram that related it to the cruise control. I think I'm a-ok without it.

[Canyonero]

I figure I'm probably ok without it especially since the '7727 doesn't ask for it, BUT I have only found that one input to the ECU related to the cruise control. No outputs to a CC module. Likely this switch is used for CC, but what other possible reason would the ECU need to know when the clutch it pressed?

My revs dip really low when I'm clutching and occasionally it will stall between gears (I just bump the clutch to restart before finishing the shift when that happens). The revs dip below idle, but come back up to normal idle immediately (about 600-800RPM if my tach is to be trusted). Cardana24 fixed that behavior on the 3.4 swapped in his Jeep by connecting a VSS. I don't have a VSS on my Trooper, but I have one ordered. Is it possible this switch could also signal the ECU not to let the revs plunge to the low idle using the IAC?

The harness I ordered from fuel injection specialties did not have tails for a VSS. I think it had a tail for the brake switch, which I don't have connected. I'm working on replacing that whole harness anyway.

[IsaacHayes]

VSS should fix your issue. I wouldn't worry about the clutch switch.

[pocket-rocket]

If your transmission doesn't have provisions for a VSS, I know on the Ranger forums some of the guys there mock up a setup to run the VSS off of the drive shaft to overcome an issue with the ECM barking about no VSS.

The only link I can find on there after a buttload of searching is this:

http://www.breaautoelectric.com/products/products1.html

It is a place that fabricates a reluctor wheel for your drive shaft yoke so you can use a VSS for electronic speedymeters.

[Canyonero]

I'm ordering one through Nevada Speedometer which is driven off the speedometer cable. They're out of stock on the one I need right now, any day they say...