Mystery knobs?

[John B]

I've been getting to know my '69 2000 Roadster and driving it a lot lately, but there are two knobs on the dash that I can't figure out.

One directly below the choke on the center console says S/BRAKE

One on the far left directly below the wiper switch says - LOCK - T


What are they??

[fj20spl311]

The lock is a throttle,
The S/brake is for checking if the brake balance circuit light works

[GeoffM]

T-Lock is a Throttle lock. Pulling it increases your engine RPM by using the throttle cable as opposed to the choke cable. Twisting it locks it in position. I switch to the T-Lock after about 30 seconds of using Choke on cold starts....just to lean it out a bit for exhaust smell reasons mainly.

S/Brake is test of the S/Brake light. it closes the contact of the low pressure warning light so that you can see if the light is functioning normally.

[John B]

Great Stuff!
Thanks guys

[68DSU]

The S-brake is a great safety innovation. Similar to the self driving technology of today but actually nothing like it. The light comes on when you don't have brakes (but you know that right away because...you don't have brakes) and pulling it out tests the light. High tech for the day and may have saved as many as zero lives.

[sports imports]

We now convert the S/brake light to become an ignitor for the GM alternators and the B now stands for battery. Broken fan belt and the B lights up. Non charging electrical system and the B lights up.

Ross
sports imports

[datsun1500]

My Dad used it for the switch for an electric fuel pump. That way he never left the pump on since the light would remind him.

[greydog]

I wired the 69 as an idiot light and the swirch triggers the electric antenna.
Works well.

Dan

[FairladySPL]

The throttle lock is a very crude cruise control. Get to speed with your foot on the pedal, hold it, THEN pull and twist the knob. It puts a lot of stress on the cable to try to bring it up to speed by yanking it on its own. Be advised the lock does NOT release when you tap the brake (like a modern cruise control would do)

It's also a good way to put the idle up, like I do on initial warm-up before a ride. Much better than keeping the choke pulled out, which puts a lot of raw fuel in the system.

By the way, while you're exploring, you will discover that the headlight switch has an optional set of contacts that power something when you twist to the right. Stock, the wiring harness has two bullet connectors for driving lights that come off this switch. I re-wired it to power a set of interior lights in the footwells.

[John B]

By the way, while you're exploring, you will discover that the headlight switch has an optional set of contacts that power something when you twist to the right. Stock, the wiring harness has two bullet connectors for driving lights that come off this switch. I re-wired it to power a set of interior lights in the footwells.

I wired mine to light up a set of foglights through a relay, no extra switch needed.