Can someone help me decipher this electrical circuit?

1996 Chevy Silverado C1500

When I turn my right turn signal on, it blinks really fast. I saw my passenger side daytime lights were not on, so got two new bulbs, popped them in and right away noticed 1 bulb is at normal brightness and the other right next to it, is like 3x the brightness and my blinker is still double speed.

So I started poking wires and testing. This is what I got.

The (my left, looking at the engine bay) day time wires:
Dark Blue
- No Power = good ground
- With Power = 00.36 volts  (this is what is sending a red flag to me)

Brown
- No Power = good ground
- With Power = 13v

Black
- Good Ground

The Right Bulb
Dark Blue
- No Power = good ground
- With Power = 00.36 volts  (this is what is sending a red flag to me)

Brown
- No Power = good ground
- With Power = 12.9v

Black
- Good Ground

Blinker (on same circuit)
Dark Blue
- No Power = good ground
- With Power = 00.36 volts  (this is what is sending a red flag to me)
- With Blinker turned on = 5v like crazy jumping around 4.5 to 5.5v

So the first thing is the red flag of the Dark Blue Wire. Can someone confirm what voltage this is supposed to be?

Here's what my Haynes Manual is saying the headlight circuits look like

 

 

This may sound crazy, but are your interior lights working? If not check the interior lights fuse.

noticed 1 bulb is at normal brightness and the other right next to it, is like 3x the brightness and my blinker is still double speed

I think G101 is bad. Turn on the headlights and check the ground for the Passenger side headlight bulb there. Location says, right front of engine compartment.

G101 is also shared by the Right front turn lamps. Without a ground there the flasher circuit has less total resistance on that circuit, means the bi-metalic strip in the flasher unit heats up faster, which is why it's flashing fast. I think.

Re-reading your post I see you checked the ground on that right front, but did you check it close to the bulb? Headlight on and flasher on too.

Scannerdanner has a really good video on this. If I copied the link correctly you can view. It's in two parts.
Bad ground.



 

yeha about to say ..do a voltage drop test

Ok so I pulled the entire headlight harness out of my truck and put it on the work bench.

Am I correct in approaching the testing of the harness in this fashion? I want to check the quality of these 5-way connections, it seems I've got like 4 of them across the harness. I want to check the integrity of the connections in the middle

I've got my multi-meter set up like this
 

Then one lead goes to one end of the wiring circuit.
 

We travel past the connection I am testing
 

To the other end of the wire
  

And this is what my multi meter is reading
 

Now when I take a fresh wire and read both ends, I get like 0.4

Here's a drawing of the wiring diagram for this specific wire. If I go and check every different end in the same method and everything brings back 2.0, is it safe to say that the connection in the middle is good?
 

If that is the case, the entire front headlight harness is good and all the multi-connections in the middle. And my problem is coming from the rear harness. I've replaced all my light bulbs, 1 of the day times burns extra bright and the blinker is on rapid fire. I thought I had a problem with the front harness. 




 

Because if this is correct, my original thought was this one burnt up melted wire, its burnt and melted up in multiple spots along its run. I originally thought this was my problem and the plan was to just replace this wire totally.. but once I checked the continuity of the wire, it brought back 2.6 which is weird... which is why I am not sure if I am testing my wires correctly.

You can see a spot of the burnt melted brown wire in the middle.
 


 

Yeah,,but did you do a voltage drop test or you checking ohms,,ohms won't do any good,,but a voltage drop would have found that bad wire or multiple problems the ground circuit did you get it fixed

scott.tucker post=50813
Yeah,,but did you do a voltage drop test or you checking ohms,,ohms won't do any good,,but a voltage drop would have found that bad wire or multiple problems the ground circuit did you get it fixed

---

Read the first post, it has my voltage drop measurements (not trying to sound mean, just pissed off with this truck)

So I just got all new bulbs, replaced the tail light circuit board (it had a burnt up connector) with a GM one...

...and now both sides are blinking fast...

Every bulb works, every bulb is brand new, why would both sides be blinking fast now?! 

 

I can understand the frustration that won't do any good so I did go back to read your first post you stated dark blue wire no power = good ground ..'how did you determine that'with power 0 0.36 volts okay I don't think you're understanding what I mean by voltage drop you must have voltage applied to a circuit to check for voltage drop how much voltage do you have on that dark blue wire at the source the light bulb with the difference of how much voltage is on the ground side of the same light bulb with the power on what is the difference between those two connecting points I understand very difficult to diagnose a problem by text message I might be willing to talk to you on the phone later tonight if you would like

Sorry I'll walk through this

I ran a power probe 4, cutting directly into the wire behind the bulb and socket of the Passenger Side Left Day Time/Blinker Light.

One wire going in is dark blue. With power on. It has 00.36v which I mentioned is sending a red flag to me. The brown wire going in with power is showing 13v and the black wire (the ground) is grounding perfectly 0v

Next is the Passenger Side Right Day Time/blinker bulb/socket.

Last is the little baby blinker on the same circuit.

And actually, I think I found a legit guy who can do the entire wiring harness for the truck, so I might just op for that solution.

These readings were for when I couldnt find out why my Passenger Side was blinking fast. Every bulb worked, then I noticed the circuit board in the Passenger Tail Lights was burnt, so I replaced it... and now BOTH sides are blinking fast!