Apparently I suck at reading wiring diagrams.

[Remow2112]

I have 76 Roadrunner I am trying to bring back to life. The fuse block looks like someone tried to cut it out of the car with a rusty saw but it is functionale and all the fuses test good. I am getting no power to the headlight switch (no lights at all, but I do get power to the dash warning lights (like brake)).

I know one line goes to the starter and another to the big post on the relay for ignition switch. There is a fusible link that runs to the bulkhead connector? I don't have an unmolested car to look at here. So if someone can give me a clue where to start checking for no power to the headlight switch and what wire runs from the batt to bulkhead connector I would appreciate it.

 

[Justwondering]

someone will be here to help soon.
I'm not that someone.
That's me sitting at the other end of the sucky-wiring boat that you are sitting in.

JW

 

[pioneer61]

How did you test the headlight switch? No power because the lights don't come on, or did you put multimeter or test lamp on the connector to the switch?

 

[Hayzoos]

Yes there is a fusible link for the headlamp circuit. But, it also serves the fuseblock on two feeds so unless you have other things not working I say the fusible link is ok. I am referencing a Haynes manual wiring diagram which leaves alot to be desired. But it identifies the feed to the headlight switch as circuit L1 12BK in cavity #40 on the bulkhead connector, #39 is 12RD, and #38 is 12PK. So you are looking for a 12 ga. black wire which has 12 ga red and pink (the same size larger wires) next to it in the connector. These wire codes are on the engine bay side of the connector. They should be the same colors on the other side under the dash, but no guarantees and my wiring diagrams do not include that detail.

 

[Aspen500]

The fusible link has a splice where 3 or 4 wires are attached. It's been known to happen where one of the wires breaks or corroded off at the splice.

If the fusible link is open, the insulation would be melted. They're made that way on purpose and if you never smelled one when it opens, well, it smells really bad, lol!

 

[Hayzoos]

Yes, I forgot about the weak splices. Something to keep in mind.

But the diagram I am looking at, the wire at cavity #40 feeds both the headlight switch and a bus in the fuseblock.

If one of the three splices between the headlight switch and the battery were bad, then something or many things else would also not have power.

With the butchering description of the fuseblock, I assume other things may have been butchered and that is what has to be determined. With the poor wiring diagram I am referencing, the tap for the headlight may be at the fuseblock supply buss, but I cannot say for sure. If so, the fuseblock butchering may be the very issue of a bad supply to the headlight switch.

 

[Remow2112]

Thanks guys, I actually tested the headlight switch the wire with power coming to the headlight switch. Nada.

Interesting, I have hooked up with the 76 wiring diagram from Mopar and it shows the headlight wire being number 27 on the bulkhead connector.

I am hoping to cut off the wire wrap today or tomorrow and see if I can ID the headlight wire. I am familiar with fusible link and I see nothing under the hood that would be fusible link wire.

 

[XfbodyX]

Many sections of FL wire. If you need up close colored wire shots I will take them. This is a 76 harness.

 

[XfbodyX]

 

[Remow2112]

Great pics! They confirm that any fusible links are long gone. What color is the wire coming from the under hood harness to the the bulk head connector in position 27? In 76 number 1 is blank and then the number seem to count left to right.

 

[XfbodyX]

Go run a jumper wire where your bright dim floor switch would be them test.

 

[XfbodyX]

Your 27 is the light green going down to the bright/dim switch if its bad or jacked inside you stop working there.

 

[XfbodyX]

27 Light Green dead center of pic.

 

[XfbodyX]

A few more that might be helpful.

 

[69-]

Just be careful with the wires. I just found two hot wires with broken insulation, before they could hit ground in my 79 camper.

Those insulation is really brittle.

 

[bugman]

fuse link

 

[bugman]

fuse link

View attachment 47425

 

[bugman]

r6 12b goes to 40 way connector pin 28 power from alternator

 

[bugman]

After 40 way con. ci 50 there splice r6 12b changes to l1 12 bk goes to light switch, added wire at splice go to fuse box powers fuse 2 3 4 and 5

 

[bugman]

After 40 way con. ci 50 there splice r6 12b changes to l1 12 bk goes to light switch, added wire at splice go to fuse box powers fuse 2 3 4 and 5