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I made a bit of progress tonight. I decided to pull the seats so that I could roll the carpet back and get to more of the harness. Looks like the melted seat wires that I fixed a while back (It is in my build thread) weren't completely fixed. I found that the seat belt wire was one of the black ones with the white stripe, and it was toasted. It also melted a bit of the brown wire next to it. I pulled them out of the connector and I will then put in new pieces.
This could have been my issue to begin with. The good news is that the rest of the wires are good pretty far back.
Orange is used often for power but the only power I can find that goes to the back of the truck are always on, not switched with the ignition: rear wiper motor, courtesy lamps, seat lumbar motors.
The only black/white stripe wires I can find is the signal for the rear hatch release and suplimental restraint gnd but those should not get power from ignition on.
There are a lot of blue wires:
Dk Blue/white: rear door jam switch
Dk blue: rear window motors, seat front vert motor, lumbar
Lt blue: high mount stop lamp, seat rear vert motor, seat recl motor
and greens:
Lt green: back up lights, drivers seat hor motor, drivers seat recl motor
Dk green: rear wiper signal, driver seat vert motor
You should have two lt greens from the firewall getting power when the truck is in reverse, the main back up light power and the trailer back up light power. You can pull the trailer backup fuse to find the main one. That gets connected to the single back up light lt green which you can find with a continuity meter from the rev lights to your options at the splice.
In general you can verify the load side wires (heading to the back) by using a continuity meter from the load back to the open wire at the break. You can verify the signal or power from the firewall by energizing that function or pulling the power fuse and rechecking.
George
From what I can see, they all come from the same connector on the fuse box. I wish there was a diagram of the wires coming out of the fuse box. That would give me pretty much what I need.
I fixed the seat belt harness wires. So I know that one of the black wires with the white stripe goes to the seat belt wire (which is now blue). The brown wire with the white stripe wasn't really melted but there was a lot of melted plastic from the black and white wire, so I cut part of it out and replaced it. For these I soldered and shrink wrapped them.
all fixed
I was able to test some of the matching wires and get a little bit more info on them, I labeled them. Here is what I came up with. Some of them don't have voltage. So I need to figure out what gives them power. And some of the ones going to the back of the car, I need to figure out what they do.
Coming from the firewall.
the 2 green wires
1 - voltage in reverse
2 - No voltage in reverse
the 2 light blue wires
1 - voltage when brake is pushed
2 - no voltage
the 2 orange wires
1 - voltage with the key off
2 -no voltage
The 2 black with white striped wires
1 - voltage with key off
2 - ground
Going to the rear of the vehicle
the 2 green wires
1 - reverse lights light up, trailer harness has voltage
2 - reverse lights light up, trailer harness has voltage
the 2 light blue wires (I am guessing one of these might be the third brake light)
1 - unknown
2 - unknown
the 2 orange wires
1 - unknown
2 - unknown
The 2 black with white striped wires
1 - Seat belt
2 - unknown.
I figured out the 2 light blue wires. I hooked each one up and pressed the brake while my wife stood behind the car. The one went to the third brake light. Process of elimination tells where the other one goes but I still don't know what it does. I got it connected and then of course it started raining.
So I made more progress last night even though I only had about 1/2 an hour of free time due to some family obligations. I tried the hatch glass and it wouldn't work. So I hooked the black and white wire up to the one that is a ground and it started working. By process of elimination that meant that the other one was for the seat belt. Now I just need to figure out the 2 light greens and the 2 orange wires. I am totally free this weekend and it is of course supposed to rain all weekend.
Last edited by Tajohns34; Jun 22, 2018 at 08:26 AM.
Got lucky with the weather today and got the wiring done. If the weather cooperates again tomorrow I plan on putting the interior back together.
The only issue I have now is that the blazer won't start. It won't even crank, and yes the battery is fully charged. When I put the key to accessory everything works. When i turn it everything just goes dead. The other odd thing is that it lets me shift through the gears without pressing the break pedal. It was starting today before I connected the green and orange lines. So I disconnected them thinking they were an issue, but it didn't help. I will double check everything tomorrow when I put the interior back together to make sure that I didn't unplug something.
It starts now, I charged the battery and reseated the battery terminals. Luckily it is nice out so I want to get it back together and finally drive it again.
So it isn't starting again. If I run 12v to the socket where the 87 pin on the starter relay is it will crank. So if I put the key to the on position it starts and runs fine.
On a positive note. I got the wiring done and the interior back together.
Does your Blazer have a remote-starter, keyless entry, or alarm? Some of those have a starter kill-switch as part of it. If you have one, use the remote to unlock the doors and disable the kill-switch, and then try starting it.
If not, you may want to test your ignition switch to make sure it is properly sending power to the starter wire when cranking.
