Why are there 2 clutch switches on my 87 turbo? What do they do? What do they control?

 

The one at the very top, is a interlock switch. If its not pressed in, the starter circuit is disabled.

The lower clutch switch when depressed, send 12v to a pin on the ECU. What it does is beyond me. Effects the idle,some say. Mine works on one car, is disabled on another. I can't tell the difference. Most all the time it does not send 12v to the ECU. Only when depressed.

Maybe someone out there can tell us exactly what it effects.

 

If you download the fsm off the internet, and download the Fuel Section for the 89 N/A, look at page F2-38. There you will find a chart that shows the interaction of the neutral switch with the Idle Circuit.

 

thanks for tthe help how much can the switches effect mpg?

 

Off the top of my head......not at all ever never. When driving, the lower clutch switch is not sending 12v to the ECU. The top switch just makes a circuit for enabling the starter.

The lower switch seems to only effect the Accelerated warmup system and the bac during the ASW period. After the car warms up, my guess is that making the clutch switch effects nothing at all.

Neither switch is the cause of poor fuel milage.

 

i thought one of them were for cruise control?



-Shawn

 

rx_7_driver.......your right. I missed that. It'd be the bottom of the two switches. Does double duty it seems. I stick with my answer about the other duties it does. Open the 89 fsm that's free online and see page F2-38 for those duties.

I think I forgot about the cruise, because my 87 n/a is a aftermaket (junkyard) cruise control and I've long since thrown away the lower (broken) switch. So it does not play a part in my cruise activity. I use the brake pedal to disable cruise, which may surprise the next owner of that car if I forget to tell him about that feature. I guarantee I was caught off guard when I delibertly pulled my BTN fuse and had the car in cruise (supplies the volts to the brake pedal stop switch).

86RXGXL....if your concerned about gas milage, check the timing, plugs, air filter , 02 sensor, water thermo switch.