NOT so EZ wiring

[kev2809]

yep, i shouldve went with something more specific to my truck for a first timer...but oh well, here we are.

67 suburban. LS swapped with modified stock engine harness.

Truck harness is a knock off ez wiring 21 circuit (i believe its knock off - bought it about a year ago maybe and off of amazon)

i want to get a little help if possible on sorting this wiring harness out. so far i have the thing mounted, i ran the tail light section up the through the pillar and along the top like original, all the way to the back, but they will need to be extended...no big deal. ran the front engine branch through the firewall. wired up the ignition switch (which apparently is for column switch and not dash and it wont reach if i route it the correct way), have the column wires bundeled together for later, and am sorting out the dash wires now.

so, i did the ignition switch first, following this thread here.
http://67-72chevytrucks.com/vboard/s...d.php?t=500794

i believe i have it wired correctly, although i havent touched the neutral safety switch but ill get into that later. any issues anyone sees? i will be working from left to right across the dash trying to wire things up along the way. currently my truck does NOT have AC, heat, or a working radio. i will be wiring the headlight switch, wiper switch, ignition switch, brake switch (4 prong), dimmer switch, and neutral safety switch.....and of course the gauges.

[kev2809]

the dimmer switch is a pre wired plug, so that was easy. i moved onto the headlight switch, where this gets confusing. i need to state first, when running the rear light section, the dome light was included, but only had the one white wire. there was an orange wire, but it was labeled "third brake light", which i left up in the wiring cavity since i wont use it.

so heres where im at. the headlight switch i ordered through gmpauls for a 67. the first picture is the diagram that came with the kit. the second pic is the actual headlight switch i have that i ordered for a 67. the third pic is what a 68 and newer switch looks like i believe. after googling for a few hours i believe i have it figured out, except for the dome wiring.

if you look at the 1st pic from the harness wiring diagram, i will need to splice the red power wire and run a jumper to the top right terminal, no problem. and looking at this youtube video from American Auto Wire, https://www.youtube.com/watch?v=Tlzdq2nVCcE
i can move the "LF Park brown wire" to the top left terminal on the switch to make it where the parking lights stay ON when the headlights come on...i think.

now, for the dome wire, i dont see any wire for it in the "dash section". stock wiring has orange and white wire plug. my harness only has the white wire labeled "dome". so what i was thinking was soldering a wire from the orange dome light wire on the roof (stock 2 wire harness, orange wire and white wire), run it back down the pillar and hook it to the "dome return" from the original diagram. would this work?

after this ill be on to the brake switch as that is confusing as well lol


i will de pin my original truck harness to use the factory plug.

[kev2809]

ive looked over the stock wiring diagrams, but i think they really wont do anything for me since im using the univeral wiring harness. i guess it all depends on how they circuit everthing

[kev2809]

any electrical gurus left on here?

[VetteVet]

Well I havent been on the forum for a few days and now I see we have a new poster with a problem.
The suburban should have the same circuits as the chevy c 10s. I didn't think that the ignition switch was in the column in the 67 surbuban or the truck. My 67 is in the dash and I believe the first one in the column is the 71 or 72. it doesn't matter because they are all wired the same.
The video you linked has the information that you need to wire the light switch so you need to look at it a little closer. I was going to post the wiring for the light switch and then I saw the video so I will just point out a couple of things.

The headlight switch power wires are the red wire and the orange wire. The red wire just powers the dimmer switch for the headlights and the orange wire supplies the juice for the other lights. Parking, brake and dome light. The white wire is a ground and it provides the ground side of the dome and courtesy lights. This is spelled out in the video and is clearly marked on the diagram of the light switch. The white wire is grounded by the light switch and by the door switches. What do you think is going to happen if you wire the hot orange wire to the ground white wire like you are suggesting? If you use the 68 switch you shouldn't have to use the jumper to keep the parking lights on when you pull the headlight switch fully on.

The orange wire is supplied by the red wire from the key switch to the fuse panel and then the orange wire supplies power to the headlight switch, the brake light switch, the dome and courtesy lights and the cargo light if you have one. It also powers the AC switch, the cigar lighter and the radio.
I will post a diagram of the circuits.




Your wiring harness since it is a universal unit , may not match the wiring colors of the stock trucks so I'm going to stop here for now. I will add that your stop light switch must be from a newer truck if it has a dual switching function. The normal switch has a normally open circuit between the orange wire and the white wire to the column harness. Don't confuse this white wire with the white grounded wire for the dome light, they are not the same.
The other function on the stop light switch is normally closed and is probably a cruise control function or for the 700R4 or newer overdrive transmission to disengage the converter clutch when you step on the brakes.

Showing the orange wire to the light switch.

[kev2809]

few things before I head to bed.

my 67 is a dash ignition like yours, but the universal harness wiring is too short to loop over the column....which is why I'm thinking it's for a column ignition.

the brake switch is a later model 4 prong, since my engine is an LS motor. it's need a 4 prong for the TCC lockup

I realize the dome light has an orange and white from the factory, and one of them is a power, the other a ground (going back to the headlight switch). my new harness dome lighting only has 1 wire which is the white wire labeled "dome". I'm assuming that one is the power wire. so since the harness only has a power wire, could I not run my own wire from.the dome plug back to the "dome return" on the headlight switch? which is basically a ground. from your diagram, original wiring has orange as hot, white ground. mine has the white as power. so I would be connecting my new harness white, to the dome light plug orange. then making my own ground wire back to the switch.

I ordered my headlight switch, dimmer switch, windshield washer switch, and ignition switch through gmcpauls for a 67.

tomorrow morning I'll look for the ignition wire diagram I found to wire it how I have it. someone posted it on here years ago and I copied it

[kev2809]

ok just got off work so have a little time to mess with it.

i bought the 4 prong brake switch because the TCC lockup needs a signal from the brake switch. so that is wired with the white and orange wires on one plug, the TCC wire from the LS harness, and a 12 volt on the other prong. the white wire is labeled "brake switch", the orange isnt labeled but has "- - - - -" on it...so im assuming its a ground. its the only wire in the whole harness that has this.

now, back to the ignition switch. i found a thread a while back that discussed this.

http://67-72chevytrucks.com/vboard/s...=500794&page=2

i think what confuses a lot of people, including myself, is when using these universal kits, with original style switches...it gets harder. we try to match how the factory wired them up vs what the actual wires in the kit have and their crappy universal diagrams. i wired this one exactly like the thread i found. i will be using the column neutral safety switch as well, which also will need wired up, but i want to stick to one thing at a time unless it interferes with something else (like which wire gets snipped to add the neutral safety switch in between??)

i also wanted to add, i will not be using a circuit board for the cluster. i will retrofit the electric s10 speedo into the stock dash, add a voltmeter, use the stock mechanical oil gauge, stock temp gauge, adding a tach, all in the stock cluster.

[doug_p]

I am fairly sure you don't need a 4 prong brake switch w/your LS. I swapped an LS and 4l80e into mine and used the stock 2 position/prong switch. The TCC signal goes to one prong and the brake to the other. As VetteVet pointed out above, the brake switch and TCC switch operate opposite each other, i.e.; the brake is normally open, and the TCC normally closed, so as soon as you actuate the brake, the brake light illuminate, while also opening the TCC portion of the switch which disconnects the convertor clutch. This is how I wired mine, and it worked perfectly.
Hope this helps -

[kev2809]

here's what I found when looking for info on the tcc hookup

https://www.67-72chevytrucks.com/vbo...d.php?t=757816

[doug_p]

Does your PCM have two wires for the TCC switch, or just 1? I only had one on mine - unfortunately, at this point I do not recall which connector and number the wire was, but I am positive I only had the 1 wire. Ultimately however, the 4 prong switch you have shown should also work as long as you wire it correctly . . . brake normally open side (so when you hit the brake the switch closes making connection and applying 12V to the tail lights) and TCC normally closed side (again when the brake is depressed the signal is opened disconnecting the TCC). Two wire should be all you need, unless your PCM calls for two relative the TCC, so at that point you would need the three.

[kev2809]

mine is the same way, only 1 TCC wire from the engine harness. I followed lt1swap and repinned my own harness so i did it the way they do theirs. I read a ton of threads on this topic and nobody mentions where the 12 volt key wire comes from lol

[doug_p]

Originally Posted by kev2809

mine is the same way, only 1 TCC wire from the engine harness. I followed lt1swap and repinned my own harness so i did it the way they do theirs. I read a ton of threads on this topic and nobody mentions where the 12 volt key wire comes from lol

Exact same site I used, and invaluable in my opinion - made it really easy to get it completed, and working correctly. Unfortunately, I wired my o2 sensors incorrectly out of the PCM and have to go back and redo those so that I can hopefully get into closed loop and have a little better mileage. Super happy w/my swap though, starts every time no matter the temp and starts quickly.

[kev2809]

exact reason I went with the swap, I don't want to mess with a choke lol. how did you pin the 02 sensors wrong? if I remember right, when the rear ones get depinned and pulled, that's it. don't think I touched the front ones.

[doug_p]

Well, I pulled every wire out of the connectors and re-ran everything on my engine and hid everything exactly how I wanted it. There are two different type of o2 sensors and either I a) bought the wrong sensors, or b) wired them wrong and actually I think I did both. To make it worse, I thought I would be "smart" and make the o2 sensor connection joint with Duetsch connectors which worked great, except when you want to replace one lol . . . shoulda just left the factory connectors on them, DUH. Anyway, just something I need to work out. It ran pretty good, just not as good as I know it could have.

[VetteVet]

Originally Posted by kev2809

ok just got off work so have a little time to mess with it.

i bought the 4 prong brake switch because the TCC lockup needs a signal from the brake switch. so that is wired with the white and orange wires on one plug, the TCC wire from the LS harness, and a 12 volt on the other prong. the white wire is labeled "brake switch", the orange isnt labeled but has "- - - - -" on it...so im assuming its a ground. its the only wire in the whole harness that has this.

now, back to the ignition switch. i found a thread a while back that discussed this.

http://67-72chevytrucks.com/vboard/s...=500794&page=2

i think what confuses a lot of people, including myself, is when using these universal kits, with original style switches...it gets harder. we try to match how the factory wired them up vs what the actual wires in the kit have and their crappy universal diagrams. i wired this one exactly like the thread i found. i will be using the column neutral safety switch as well, which also will need wired up, but i want to stick to one thing at a time unless it interferes with something else (like which wire gets snipped to add the neutral safety switch in between??)

i also wanted to add, i will not be using a circuit board for the cluster. i will retrofit the electric s10 speedo into the stock dash, add a voltmeter, use the stock mechanical oil gauge, stock temp gauge, adding a tach, all in the stock cluster.

Looks like you have a handle on the wiring, so all you need to do is figure out which wires to use in the universal harness.

[dmjlambert]

"which wire gets snipped to add the neutral safety switch in between?"
It is the wire that goes from the "purple sol" position on the ignition switch (that you show in your first picture above), to the starter solenoid "S" terminal.

[kev2809]

that's what I was thinking. but I have a bunch of wires that go to the engine bay area that I'm either not going to use, or will maybe route to something else. i.e. choke wire. I'm out of town now but will back later today to look at them. one is a purple solenoid wire though I believe.

I got the rear tail lights mostly in their resting places. had to lengthen just about all of them though. that rear harness has a blank yellow wire that when I traced back to the fuse block, it was tapped together with the choke wire that goes to the engine bay. I just taped it up in the harness and left it.

I will try to get those soldered to the rear tail light plugs and then get back to the dash wiring, starting with the headlight switch again. using my 67 switch that I bought, I'm hoping wiring it like I said above will work. I already have the switch and it's new, so I don't mind making the jumper wire. it's the dome return that was confusing me since this ez wiring harness doesn't have a ground return from the dome lamp back to the headlight switch


thanks for yalls help. I know I ask a lot of questions but I really want to do this once and not worry about my truck burning down one day

[kev2809]

found out that blank yellow wire that i taped up that goes to the rear is the fuel pump wire, which i figured. my fuel pump wire is wired into my ls harness, so i will use that one instead.

got the head light switch pinned and installed. hope it works right lol. below are a few pics of how its pinned. that white wire wasnt in my harness...but i ran it up to the white wire in the dome plug for the ground. my harness dome wire is also white, but its labeled dome light. i ran that one to the orange wire in the dome plug harness. also swapped the parking light wire like the video above explains, that way my parking lights stay on with the headlights.

so moving on the wiper switch. this one is odd. so, in the ez wire harness, it has one blue wire labeled "wiper". this should be the 12 volt feed, but hooking it up is confusing. in my original harness, the plug that plugs into the wiper switch on the dash has 3 wires. following the harness down some i run into 2 different plugs that go to the wiper pump. i read a little on the stock wiring and seen most of these wires were ground, and the only power wire was the original yellow (which in the new harness, will be blue). i also know the switch itself is the ground, meaning no ground wires. i would like to just wire up the wipers to work. dont really care about high/low speed, or washer pump. i never intend to drive it during bad weather anyways. so, could i just run this blue wiper wire to the location where the original yellow wire went on the wiper motor, add a 2nd wire in this pin, and run it back to the power location on the wiper switch plug?

[kev2809]

here is a pic i robbed off the forum showing the multiple plugs. i know one of the plugs is for the washer pump, which i dont care about really. you can see the plug on the left is pinned with 2 yellow wires together. im assuming one jumpers over to the washer pump. instead of sending over a jumper, could i not just run it back to the wiper switch?

also not sure what to make of the other wires in the plugs..

[VetteVet]

You cannot use the blue wire to the wiper switch. It is the power wire (OEM yellow wire)
from the fuse panel to the wiper motor. The wiper switch is grounding only for the two speed motor. All the wires that go to it are for the grounding side of the wiper motor. This includes the wire for the washer motor. You have to be careful wiring the bl/yellow to the motor. The diagram from the factory is wrong. It shows the yellow wire joined with the black wire in the factory diagram.

You will need to use the fuel pump wire in the LS harness for the fuel pump on your engine. The OEM did not have a fuel pump in the tank. You probably know this, but others reading your post might not.

[kev2809]

the blue wire is from the ez wiring harness. it's labeled "wiper" is this not the same as the stock harness yellow 12 volt wire?

so your saying the actual switch does not have a power wire going to it?

[kev2809]

after digging around vett I see what you are saying. I was trying to look at the stock wiring diagrams and kept seeing 2 versions. I found this thread with you explaining it.
http://67-72chevytrucks.com/vboard/s....php?p=7873879

and also this picture in there makes it really simple. so I go this route...my blue wire will go to where the yellow wire goes in this diagram. and I will jumper it to the top plug to the washer pump. and looks like I will need to add all of the other wires that go to the wiper switch...and I need to see what that stock white wire is there

[LS short box]

Just FYI on the TCC switch. On the older gen three (24 tooth crank reluctor) LS autos the ECM wants to see a "open" curciut when the brake is pressed.
On the newer gen four LS autos that use two ecm's, one for the trans and one for the engine the ecm needs a 12 volt signal when the brake pedal is pressed.

[kev2809]

donor is a 2002, guessing that was the older version?

[VetteVet]

The white wire is the power wire from the fuse panel shown in this diagram
and the real time wiring looks like the second diagram. The blue wire is a ground wire back to the switch for one of the wiper speeds. You may get confused if you use blue for both wires.