Ok Ok..let me exercise my ebay purchases

I bought the Nissan Emission Control Workshop Manual some time ago, and it's in there.

It's referred to as an 'Amplifier'. It is part of the 'Throttle Opener Assembly'

It's only fitted to the Manual Transmission models.

Pub No. SM6E-EMC0A0, Page EC-11:

"The speed detecting switch is part of the speedometer assembly and is installed in the speedometer. The amplifier prevents damage to the speed detecting switch which actuate the throttle opener only when the car speed is above 10km/h."

Both the B210 and B120 have this device (although they have a different connector and mounting bracket).

it's probably a voltage stabiliser.

so why does it go into the speedo and earth when the speedo is at 0 kph?

id think its more of a switch for something that doesnt need to be working when stationary

Didn't we figure it was for pollution control...

Or is it a antique form of speed limiter .. Although, I thought it was generally accepted that the 'valve bounce in 4th' method kept speed under control.

Actually, after a long overdue bite of dinner... it's part of the dash light dimmer circuit.

edit2: after actually reading the thread..I return to being completely befuddled as to it's true purpose.

I believe that it is a speed detecting switch amplifier & is part of the polution control system.

Without actually checking, I suspect that it is somehow linked in with the BCDD system [Boost Controled Deceleration Device where the 'boost' is actually vacuum]

Many Datsun models in the late 70's & early 80's had these & the speedo has a switch that returns the system to full idle setting at speeds below a preset value of somewhere between about 6 to 8 mph. [or is it kph?]

Aussie series one 910 Bluebirds with manual trans had something like this.

there was a thread on this about 3 weeks ago i think everyone had a stab at what it was

any idea on what the name of the thread was....or if there were any decent answers?

this is it i think in a rush clicky

We never figured out what it was:


Anyone know? It is a Matsushita 68600-AN8500. Seems like a Nissan number:
68 Instrument section

ok i no longer care what it is as its not the reason why my speedo wasnt working, turns out that the late utes use a slightly different speedo cable to other datsuns

long story short, speedo cable was pressing against the speedo to hard and not letting it move freely

so ill just put the kph face on one of my coupe mph speedos

but just for the sake of finding out what this little doover does
one wire gets power from next to the tacho, another wire goes into the speedo and seems to ground when the needle is at 0 and the other heads off into the engine bay somewhere