Installed parallel kickdown switch in my 88 s4and it works great giving car very lively response when engaged.I also installed a light to indicate when kickdown switch is activated and have hit a problem in that kickdown activates when circuit is open which turns light off,- as I understand trans solonoid is active constantly and kickdown operates when circuit is opened either by hard press on accelarator or with parallel kickdown, i have read posts where people have installed lights with kickdown switch and had same problem, others seem to have light working when kickdown is engaged but details were sketchy

 

The kickdown works as follows:

- Power is supplied from the 15 bus (ignition-switched power) thru Fuse #10 to the normal kickdown switch under the throttle pedal.
- Power flows from the switch to the input side of the normally-closed contacts on the KickDown Relay.
- Power flows thru the relay to the Kickdown Solenoid on the transmission, causing a change in transmission control pressure, making the transmission more likely to downshift and more reluctant to upshift.

The Kickdown Relay is operated by the LH ECU - when the engine hits redline, the LH ECU interrupts the flow of power to the Kickdown Solenoid, opening the contacts, interrupting the power to the kickdown solenoid, causing an instant upshift.

I am not aware of any 928 which has constant power to the kickdown switch or solenoid.

If you have a light installed in parallel with the switch, it will go off when you close the switch. You need to install the light from the output side of the switch to ground.

 

Wally thanks for reply and detailed info. Will do as you suggest and hopefully have light operating.