[Ben M.]

That is the transmission controlled spark speed sensor. It works in combination with the solenoid on the intake and temperature sensors on the engine to keep vacuum advance off of the distributor under 25MPH or not above a certain temperature\warmed up (the temp changed year to year from 1971-1974). 1972 only thing on transmissions from GM cars.

[Gary H]

Originally Posted by Ben M.

That is the transmission controlled spark speed sensor. It works in combination with the solenoid on the intake and temperature sensors on the engine to keep vacuum advance off of the distributor under 25MPH or not above a certain temperature\warmed up (the temp changed year to year from 1971-1974). 1972 only thing on transmissions from GM cars.

Well, that's a new one for me! Never heard of that before. Learned something new!