Part IV


By E. Meloan

(This article was originally published in the September, 2003 issue of the Spark Coil.)

Let’s continue our discussion of the Model T electrical system.  In previous articles, we talked about the early 1909 to 1914 system, the 1915 system and how to re-magnetize the magneto.  Now, we’ll move on to the later layout that included the generator and electric starter.

The electric starter had been used since 1912 on Cadillac and made the automobile a convenient form of transportation for the ladies.  The 1919 Model T closed sedans were the first to appear with electric starters and the open cars followed by 1921.  The starter was part of a package that included generator, starter and demountable clincher rims.

The addition of the generator meant that the unreliable 1915 lighting system could be replaced with a more modern six volt system that didn’t dim with low speeds or burn out the bulbs at high speed!  This represented a real improvement in safety and convenience.

The electric starter is operated by a button in the floorboard.  Now, when the driver forgets to retard the spark, it is the electric starter that takes the brunt of the kickback and not the driver’s wrist or arm!  All in all, the generator and starter was a great improvement in the “T” and long overdue!

Our “improved” wiring system now included a six volt storage battery located under the floor behind the front seat in touring cars and under the floor of the trunk in coupes and roadsters.  The negative terminal of the battery was attached to the frame of the T with a heavy braided strap.  The later Model “A” reversed this arrangement and grounded the positive terminal.  It’s not unusual to see Model T’s with the incorrect positive grounds like the later A’s had and they will work but that’s not how they were originally wired.

From the battery, a heavy cable traveled forward to one terminal of the starter switch.  One note of caution here… Do NOT use the 12 volt replacement cables from your local auto supply!  They are not designed to carry the higher current needed by the 6 volt starter.  A second heavy cable is attached to the other terminal of the starter switch and travels forward to heavy copper terminal on the starter assembly.

A smaller wire is also attached to the starter switch terminal which has the battery cable and it travels up to the terminal block on the firewall in the engine compartment.  This smaller wire carries the current to operate the lights, horn and coils, when the key is in the “battery” position.  Don’t make the mistake of attaching this wire to the same terminal with the starter cable since that terminal only gets current when the button is pushed to operate the starter!

The firewall terminal block is a great place to troubleshoot electrical problems and, it’s also a great place to cause them too!  With age, the terminal blocks frequently will NOT keep the screws tight and this will cause poor connections that are the devil to find!  If your terminal block screw holes are stripped (a common problem) you will be unable to get good tight connections and every circuit in the Model T travels through the strip except the starter!  Many a problem with lights, and rough running can be traced to loose connections on the lowly terminal block!  Save yourself a lot of headaches and repair or replace this little block!  We’ll continue our electrical discussion next issue.  In the meantime,

See you down the road…