Question w/ Chrysler 70 hp wiring harness/tach

huskerdaninva

Petty Officer 1st Class
Joined
Jun 18, 2009
Messages
240
Hey all, I'm re-installing my wiring in the Valiant and I have a question. 1969 70 hp model 7071 serial 5145. I have the original owners manual and the instructions show the terminals and which wires go where. Well, the owner's manual shows the white (tach signal wire) going to the upper "M" terminal on the back of the ignition switch. (There are two terminals marked "M"-upper and lower) While my Glenn's repair manual has a very detailed complete wiring diagram that shows the same white tach wire going directly to the signal terminal on the tach. If I put the white tach wire on the back of the iginition switch would I run a jumper from the switch to the tach signal terminal? What is the benefit of running to the ignition switch and then out to the tach? Which is the "preferred" method? I hope this all makes sense! :redface:
 

Frank Acampora

Supreme Mariner
Joined
Jan 19, 2007
Messages
12,004
Re: Question w/ Chrysler 70 hp wiring harness/tach

Oh! You can't do that at all! No tach ever made will work on a 70 HP Chrysler! LOL

Nah! Either method is correct! The "M" terminals on the ignition switch are only used for engine stop on magneto or later electronic ignitions. The two "M" terminals are isolated with the switch on and in continuity only with each other when the switch is off.

SO: You can connect the white to one "M" and run a jumper to the tach signal post. This is convenient if the wires in the cable are not long enough for the white to reach directly to the tach.

OK?
 

huskerdaninva

Petty Officer 1st Class
Joined
Jun 18, 2009
Messages
240
Re: Question w/ Chrysler 70 hp wiring harness/tach

Thanks Frank, I understand 100%. Your explanation goes the way I was thinking, but I like to have verification and you fit that bill very nicely. Appreciate the info...
 
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