1965-1966 gmc truck wiring questions

[mnky30]

i have a 65-66 gmc truck and was wondering if the wiring is the same as a chevy truck that same year. my problem is that all the wiring diagrams i have seen on chevys say that the wires coming fron the drivers side harness go to the horn relay and the voltage reg then a wire runs accross the front of the radiator area to the battery and mine does not have a voltage reg and i am confussed on where the power goes in to the cab.any help would be great thanks.

[VetteVet]

Here is a pic of what your voltage regulator and horn relay should look like if it's a stock truck. The ballast resistor for the coil is on the left.

[mnky30]

my wiring comes out of the fire wall in a plug and runs to the horn relay and headlites then on the passanger side it comes out of a plug with 6 terminals and runs to the engine and battery are and i don't see were the voltage reg goes.

[joe231]

has it had a alternator upgrade? if so you won't have a visible voltage regulator, as they are internally regulated. your horn relay acts as a power distribution block

post pics if you can

[mnky30]

as soon as it stops raining i will post pics. i not sure if it has had a alt update because i got the gmc cab back in 2002 and the 60 chevy frame cab and bed in 2006 and the chevy did not have any wiring that was good and the gmc cab was a basket case all wiring was on floor board in cab plus lots of other things. just getting the thing finaly put together. so that is what i am starting with. the gmc cab is now on the 60 frame. the cab of the 60 was totally rotted out cab

[joe231]

yeah that is a newer internally regulated alternator in that last pic
you don't need a regulator
that is also a newer motor, accessory holes in the heads and newer style alternator bracket

[mnky30]

yea the motor is out of a 1982 chevy c20 pick up it is a 350 and the suspention is out of the same truck i'm running 3/4 ton front and rear. the tranny is a turbo 400 out of a 80 c20 pick up the alt is not to sure what it is out of but i had it laying aroung and is new. i know it is a new style with inter reg. here are some pics of my wiring i am working with the plug has 6 terminals the colors are red,blue,purple,white,green and brown

[joe231]

here is the wiring on our '66
kinda hard to see colors in the pics cause there is paint on the wires











it is a little different than yours, 6 wires, 1 heavy gauge red and 1 black with white stripe go to the power terminal on the horn relay, green and tan go to the headlights, black is the horn feed, and brown goes to my alternator

[joe231]

ours is the same as this '64 diagram, minus the changes for the alternator
this truck was built from several trucks. it has a '63 frame, '66 cab, and now looks like it has '64 wiring

[mnky30]

the six wire one i am talking about is coming out of the passenger side. the wires you are showing me are simaler to mine on the drivers side by the brake booster except there is only three wires at the horn relay and one going to the horn.

[joe231]

ok, well
guess I don't know what you are asking....
you were asking about the regulator and I showed you how ours is wired with an internally regulated alternator
the wires on the pass side have nothing to do with the charging system. it is the starter, coil, and guage/dummy light sensor wiring that can be seen in the upper right corner of the diagram...
so what was the question again?

[mnky30]

ok i understand that i see in your pics is also some thing i amgoing to look at in the am. on my harness on that side you hace pics of i don't see any other wires beside the ones to the horn relay and the head lites. my relay looks like yours but with out the other wires running to the voltage regulator. there is only 5 wires on that plug i have. on the other side with the six wires do you know which wires run were. and were would the power be coming in to the cab to supply the rest of the truck?

[mnky30]

i just don't want to end up burning some thing up in the cab or frying my wiring harness that i have.

[joe231]

our truck has gauges not lights, and a manual oil pressure gauge.
what does yours have?
mine only has 4 wires, the green runs to the temp sensor, the purple goes to the s terminal on the starter, a black goes to b terminal on the starter, and a black wire covered with a white woven cover goes to my HEI. I don't have the original coil wiring

[mnky30]

mine has lites for the dash. but i am going to make my own gauge cluster with tach speedo fuel volts temp manual and manual oil.

[joe231]

yeah your colors aren't jiving with this diagram, maybe someone has a '66 diagram?

[mnky30]

yea i know that is what i thought since mine has the large red wire and one more that is not on the wiring diagrams. i'm lost and thanks for the help.

[joe231]

not a problem, i will look around for a different diagram

[joe231]

found one
think it might match your colors

[mnky30]

yea that looks more like my wires. i tested the wire harness today and the blue,brown,green wires run to the insterment panel and the purple is to the start and white is to the coil and the red powers the ignition and the fuse box.thanks for the help joe231

[joe231]

you are very welcome
i believe...........
your green is your temp gauge wire
blue is oil pressure
brown goes to your battery terminal on your starter
purple goes to the start terminal on the starter
white to the + terminal on the coil
still don't know about that red

oops, i missed what you said about the red....that seems odd
did the wiring come with the '66 cab?

[mnky30]

yea the wireharness was in the cab when i got it. there was lots of stuff in the cab. like i said it was just the cab and front clip 2 sets of doors one set on it one set in the cab no seat. got it for free in 2002 can't beat that. just needed a frame and bed engine and trans. good start thow.

[joe231]

heck yeah!!