I have a problem with no instrument lights on mine too. Two different clusters and no lights. I'll check to see if I have power at the fuse and then probably check the headlight switch. I've see that mentioned here a few times in the past.

 

I should clarify. The resistor is not inline with the BLACK with GREEN stripe wire; it IS the BLACK with GREEN stripe wire. It's a specially-doped resistance wire that builds resistance along its length. The total value is 8.5 ohms. The only way you would be able to read the resistance of it is to disconnect the accessory bus behind the fuse panel, then probe between the accessory bus and the end of this resistor wire. It's not a practical measurement to take.

The BLACK with GREEN stripe wire shares its crimp terminal with a BLACK wire. If you peel the harness back enough, you will see that the BLACK wire is taped off. The BLACK wire is a dummy wire. It's there because the BLACK with GREEN stripe wire itself is too thin of a gauge to take up a crimp terminal. The BLACK dummy wire "adds" gauge to the BLACK with GREEN stripe wire to create a solid crimp.

Even though this is a resistor wire, if you disconnect the cluster connection and measure the voltage at the BLACK with GREEN stripe resistor wire, you should still see 12 volts. When you saw 0.06 volts, are you confident that the meter was grounded properly? That is to say, if you kept the ground lead of your meter in the same place but moved the signal lead of your meter to a known-good location, do you see 12 volts? The resistor wire hardly ever goes bad, so I'm a little surprised to learn that this may be the cause.

 

On another note, I did notice something of interest earlier. The 3-"port" yellow connector that the windshield wipers plug into has no power going to it. I tested all three sockets and got no reading from it.

I'm going to recheck it again tomorrow, plus my fuses and see exactly where I am with it. Maybe that is the reason why I do not have wipers at the moment, when I know they worked when I got the truck.

 

The 3-port YELLOW connector connector is the spare accessory feed. It should have a heavy-gauge BLACK with GREEN stripe wire running to it. It should have 12 volts with the key in RUN or ACCY. It is protected by the ACCY fuse in the fuse panel. If you have no power at the accessory feed, check to make sure you have power on both sides of the ACCY fuse with the key in RUN or ACCY. If you have power on only one side of the fuse, replace the fuse.

I double checked the 1976 factory wiring diagrams, which I'm not confident I'm interpreting correctly. However, there appears to be two options: one where the resistor wire is unfused as I have described, and one where the resistor wire appears to be protected by the ACCY fuse. The latter goes against my understanding and experience, and the diagrams give no indication as to why one would be used over another. However, in this configuration, a blown ACCY fuse could cause the behavior you describe. I apologize for the confusion; I realize this goes against what I described earlier. Give the ACCY fuse a look.

The option split is shown in the top-left corner of this page: http://fordification.net/tech/images...aster_3of9.png

 

FMC I gotta thank you again for the info. I cleaned all the contacts in my fuse box this morning and reinstalled my fuses and lo and behold my instruments and wipers work again. I do appreciate all the info you gave me about this issue. Now I need to get my heater fan going and ill be good electrically for awhile. Thanks again!

 

Glad to hear you got it worked out.

 

Just as something to throw out there, the option split on the fused/unfused resistor wire could be due to options the truck might have come with. My truck came with idiot lights for oil and alt, while others had the full gauge set. It also could have something to do with what options the truck left the factory with, or whether or not it left with A/C. I know that doesn't make much sense realistically, but Ford has done some crazy things over the years.

 

I was thinking the same thing; it probably had to do with what options the truck came with, since one diagram covers all trucks for the model year. It wasn't immediately obvious why one configuration would be used over another in this case; to me it seems like it would always make sense just to have everything downstream of the fuse. Who knows.