Clutch and BOO

[Desert Patina]

What does the engine computer do with the BOO (brake on/off) or the clutch (neutral drive input) switch?

I think I've hit the end of my ambition, and those are the last two circuits the 85 isn't geared up for that the LA3 is.

I suppose I could wire up the BOO easily enough, but the clutch switch seems to be routed in crazy ways.

On a similar note, anyone ever looked at all the shenanigans actually going on behind the scenes with the premium fuel switch? Why you have three relays?

I'm leaving that circuit alone, but seriously...

[MikeFleming]

The BOO, clutch and NDS switches are not used in the SVO so there is no wiring for them.

On the 87/88 TC, they are primary inputs for the cruise control.

The 1984 SVO Supplement to the FSM has a seciton describing what the TWO relays do for the Regular/Premim Fuel switch, One of them is used to switch on/off the Boost Ourput signal from the EEC to the BCM (BCS on larger models) and the other is used to switch on the input to the EEC to put it into Premium mode.

On the SVO, the "third" relay you refer to is for the fog lamp circuit.

[Desert Patina]

Thanks.

So the ECU controls the cruise control on the T-Birds?

Also, what exactly happens when the signal from the EEC to the BCM is switched on and off?

thanks again...

[MikeFleming]

Also, what exactly happens when the signal from the EEC to the BCM is switched on and off? The EEC Boost Control output signal is a 40-Hz square wave pulse-width-modulated signal. When it grounds the circuit, the BCS opens, allowing air to bypass the wastgate diaphragm.