In my case there's four wires on mine.
Red with power in.
Blue with a connection to the distributor
Brown which goes back to the tach I believe
Green which goes to the + on the coil.

I can verify the Red as 12 volts in.
The brown I don't care about
The blue though I'm not sure how I could test the output or whatever with
how it works.
The green to the coil I'd love to test with a test light, but I'm not sure
what really comes out of there.


"tony thomas" wrote in message
news:y2Mne.9908$xm3.2581@attbi_s21...
Technically there is no way that I know of. However, there is a way to
verify all the signals coming into it are there and if the spark is there.
If all inputs are right and no output then you have verified the switchbox
is bad.

--
Tony
my boats and cars at http://t.thomas.home.mchsi.com

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"Chris" wrote in message
. ..
I've heard from some that there are tools at the merc dealers to test
switch boxes, however, when I went to an old merc dealer who tests old
motors he said that there was no way to test a switch box.

Specifically, 70's era switch boxes.

Is this true?