How do you change the ignition switch on a 1986 nissan truck

Tap into the ignition switch and run power to the radio.

sold all over earth, what country> we cant guess this....
don't break the brakes....!!!
my guess, you meant the
brake lamps are on keys in pocket. and the battery lamp is dash(charge) glows, keys in pocket. right?
and battery cable kills all this illegal states above. sure.

86 nissan PU.
720 PU>? Datsun>?
or D21 Nissan ( 1986 Dat-SUNS became NISSANS. in USA)
Model years 1986.5 (second half) and later were called Nissan Hardbody Trucks, chassis code D21.

D21 are called HARD BODY trucks. mid year changes.
so???? which is yours.

as you might not ,know , the models are wired diffrent by different exact models and country.
long ago , i had the 86 with the VG30 V6...

so i will roll the dice and answer for
D21
ok?

things off stay on, 101
bad wiring, hacked in wiring, radios,alarms and other things.
all can cause this..... its old and is common on old cars.
but if wiring is not hacked, (id see that in 10seconds in person)
no hacks.
gas engine car not diesel.
USA 86 body
brakes
Im looking now at the schematic and this car has a hot at all times
brake lamp switch. (foot pedal switch)
SO only a bad switch can cause this.... period
now the dash charge (battery ) light stuck on.


my online source ,has the alternator system missing.
so can not comment.
the lamp gets its power from the key switch
if the key switch fails , all warning lanps glow not just the
charge.(battery)
so its not that
my best guess is wiring errors, that put power the the cluster
key off. id bet that is it .

wiring errors to the ignition output is side, key switched power is failing.

Never heard of anything called an 'intake coil'. The intake is a tube supplying fuel to the combustion chamber. The spark comes from an ignition coil.

https://www.google.com/search?q=1986+Nissan+Pickup+intake+coil

..

sounds like a fuel filter, or fuel pump, or could be spark related such as coil breaking down or bad igniter if so equipped

Have you checked if any power goes from ignition switch to the coil?

Chang the head light switch also

How did this start happening? Have you changed anything recently. Commonly it too rich in petrol or timing is too advanced.

Try mass air flow sensor.

sack yoy

electronic brain that controls the ignition is dead.