1966 steering column wiring question 66 gurus please help!

[mattyq17]

Okay next question, which wires from Vipers picture below should have power? Using a test light 460(Yellow) has power with key on or off but nothing else has power, whether the key is on or off. I am thinking that wires 810 810A should have power as well, but they don't. Nothing is hooked up to the steering column at this point.

 

[DirtDonk]

Wire 810 from the stoplight switch will only show power when you push on the brake pedal to close the switch. Did you do that during testing?

And the wires from the turn signal and hazard flashers might not show power with just the volt-meter trying to see it. Not enough to activate the flashers. I don't know that for a fact though. Just thinking it might be the case.
Maybe a test-light instead of a meter? Or are you using one already?

Paul

 

[mattyq17]

Wire 810 from the stoplight switch will only show power when you push on the brake pedal to close the switch. Did you do that during testing?

And the wires from the turn signal and hazard flashers might not show power with just the volt-meter trying to see it. Not enough to activate the flashers. I don't know that for a fact though. Just thinking it might be the case.
Maybe a test-light instead of a meter? Or are you using one already?

Paul

Paul I am using a test light, not a volt meter. I did press the brake pedal, and still got nothing, time to start tracing wires back this weekend. I did see that there are two wires coming off the master cylinder for the brakes but I haven't traced them back under the dash. Isn't there supposed to be a brake light switch somewhere, or is this a 66 oddity?

 

[DirtDonk]

That is the brake light switch. The early models (perhaps all with the single reservoir master) had a fluid pressure activated brake light switch. Later they went to the pedal-arm mounted switch we've become more familiar with.

So if wiring stays true to at least some form, the IN wire gets it's power from the headlight switch. It's protected by the headlight switches' built in circuit breaker and is why it does not have it's own fuse in the main panel.
So at that pressure switch, one wire is power IN and will have power all the time. The other one is power OUT to the column when you press the pedal.
Perhaps your switch is bad, or you did not press the pedal hard enough? You'll know in a flash if neither wire has power though.

Paul

 

[DirtDonk]

Oh, and similar to that, both the hazard and turn signal flashers have power at one of the two wires. The hazards at all times regardless of the key position, and the turn signals only when the key is in either RUN or ACC.

The only time you see power OUT from the relay/flasher/thingy is when a load and ground are applied at the far end. In other words, when the turn signal or hazard switches are tripped, the load of the light bulbs activates the thermal switch inside the flasher units.
Even though you're using a test light, perhaps that's not enough load to energize it? I don't know, but it's a possibility.

You can test the incoming power wire to each module for sure. I'm just not sure how consistent the power would be from the module/flasher/thingy to the steering column with only a test lamp to light.

Maybe Viper will chime back in and enlighten us.

Paul

 

[mattyq17]

Thanks Paul, I got some wire searching to do this three day weekend!!

 

[mattyq17]

Oh, and similar to that, both the hazard and turn signal flashers have power at one of the two wires. The hazards at all times regardless of the key position, and the turn signals only when the key is in either RUN or ACC.

The only time you see power OUT from the relay/flasher/thingy is when a load and ground are applied at the far end. In other words, when the turn signal or hazard switches are tripped, the load of the light bulbs activates the thermal switch inside the flasher units.
Even though you're using a test light, perhaps that's not enough load to energize it? I don't know, but it's a possibility.

You can test the incoming power wire to each module for sure. I'm just not sure how consistent the power would be from the module/flasher/thingy to the steering column with only a test lamp to light.


Maybe Viper will chime back in and enlighten us.

Paul

Paul I have no power to either of the flashers as well as no power to either wires on the master cylinder.

Another question should wire 44 turn signal 12V have power with the key in run?

The headlights and running lights work so I know that part of the headlight switch is working.

 

[mattyq17]

Oh and they are new flashers and I used a test light I need to pick up a volt meter and learn how to use one!!

 

[DirtDonk]

Paul I have no power to either of the flashers as well as no power to either wires on the master cylinder.

What's the condition of the fuse panel? And are you getting power to all contact points? Some are bussed to have power straight from the main power wire (always hot) and some are bussed along with the other accesories with the key.

Another question should wire 44 turn signal 12V have power with the key in run?

I don't think so. The #44 wire is the side of the turn signal flasher that goes to the column. So no, it will not have power until the turn signal switch is activated.
The other wire to the flasher (#8a in my diagrams) is fed power by the 14a fuse in the panel.
Check that other wire with the key in RUN and ACC then.
If I remember, my turn signals worked even in the accessory position of the key, so that seems consistent with what we see in the diagrams.
But it's been awhile since I've spent much time in one with stock wiring!

The headlights and running lights work so I know that part of the headlight switch is working.

That's good. But power for the turn signals is not from there.
In my diagrams the hazard flasher gets power through the 20a fuse in the panel.
Obviously the turn signals are on a switched fuse, while the flashers are on the always powered buss.

My diagrams are the "standard" ones that apparently are good for later '66 through '70, but as we've found there are things with the early '66's that don't follow.
Hopefully these are not some of those!

Paul

 

[DirtDonk]

Oh and they are new flashers...

Remember, "new" does not always mean good.
In your case right now we can presume them to be good because you're not seeing power even to their input sides. But once you have power supplied to them and still can't get something to flash, don't ignore the fact that parts can be bad right out of the box.
Makes diagnosis a real pain these days!

No more presumed innocent when it comes to buying new parts.

I'm not sure how to test one either, but I imagine it's not too difficult. Maybe an ohms reading (resistance) when you get your meter? Maybe a load test by applying voltage and throwing a light bulb to the other end? Not sure, but someone's done it I would think.

Paul

 

[mattyq17]

Funny, I almost put that in my post Paul, just because it’s new doesn’t mean it’s good.... so I checked the fuse panel, it’s in good shape appearance wise, the fuse holders need to be cleaned up a bit though. I checked for power at each fuse and here are my results.

Heater has power with key on

Dome I need to get a fuse for it

Cigar lighter has power with key off and on

Radio turn-stop LP instr pnl (the small fuse in the middle) has no power, key on or off...
So I am thinking that is my issue.

Paul what is the next step to diagnose this issue?

 

[DirtDonk]

Yeah those contacts are pretty rough looking.
What does the back side of the panel look like? Can you shoot a pic of that too?

If you have power to the heater, then you have power coming in from the Black w/green wire to the main switched buss area of the panel. Which means the power is lost right there at the fuse panel.

The small fuse is for instrument panel lighting only, and will only have power when you turn the headlight switch on to at least the first pull.

The middle fuse above it, the 14a Radio/Turn/Stop fuse is the one you need to work on. Find out why the power is not reaching it. It's on a common buss bar with the 20a heater fuse and probably one of the studs to the left.

By all means post up a good image of the other side as well. Steve83 was trying to archive any differences in the fuse panel wiring, layout and markings for the record.
Great pic by the way. Let's see if we can narrow this bugger down!

Paul

 

[DirtDonk]

Oh, and on the back of the panel you will see all the wires and various buss-bars. The Black w/yellow wire is the power feed for any fuse that has power all the time and the Blac w/green stripe is the power feed for any fuse that is controlled by the ignition switch.

You might consider getting that Dome Light circuit working too when you can. Just in case it protects more than just the dome light (that yours probably does not have anyway) so trying to trace a problem doesn't give you fits.
I'm not really sure that it does share duties with other circuits. But it would be good to have it all up and running just in case.

Paul

 

[DirtDonk]

One last thing. Unless the panel clips are just too far gone, you might try soaking it entirely in some Evapo-Rust liquid. I did that to a borderline fuse panel and it came out looking almost brand new.
Since yours is just hanging there it should be a piece of cake to get it done.

With luck the buss-bar is not rusted through on the backside, and the clamps themselves are not compromised by rust through.

Paul

 

[mattyq17]

If you have power to the heater, then you have power coming in from the Black w/green wire to the main switched buss area of the panel. Which means the power is lost right there at the fuse panel.

The middle fuse above it, the 14a Radio/Turn/Stop fuse is the one you need to work on. Find out why the power is not reaching it. It's on a common buss bar with the 20a heater fuse and probably one of the studs to the left.
Paul

Ok thanks for the clarification Paul, the 14a fuse does have power I forgot about that one. I will get a picture of the back side and post it.

 

[mattyq17]

Here are a couple pics the back side and a light that is on the bottom of the dash, dome light or aftermarket? Either way it has all wires cut to it.

 

[DirtDonk]

Aftermarket light. Original (optional) map light was a single bulb with a mount that looked like a little shiny silver "hat" around it.

The fuse panel should be cleaned and wire-brushed (battery disconnected of course!) and checked very closely. That's a bit of rust and crust going on there. And look at the Orange wire there too. Looks like it's been way too hot and started to burn. And guess what that wire is for!
Resistance (rust) is heat. And heat is resistance. So a burned wire and reduced voltage is an inevitable result of the cycle of rust/electrical resistance.

You may or may not be comfortable with this suggestion, but because your panel is off and accessible, I would have to say now is a great time to replace it entirely.
Not saying you need to re-wire the whole truck. Just that swapping in a more modern (or even an old replacement that's in better shape) would very likely be a good long-term solution.

I've see panels in much worse condition than yours, but have also seen plenty in better shape that didn't work all that well either. They've been improved upon over the years, so if you're not into a religious restoration at this point, a new style like some other members here have used might be a good thing.

Here's to snowballs rolling downhill!

Paul

 

[mattyq17]

So there is no power at the brake sensor switch on the master cylinder. I am thinking the switch is bad.

 

[Viperwolf1]

So there is no power at the brake sensor switch on the master cylinder. I am thinking the switch is bad.

No power at either wire means the switch isn't getting power, not that it is bad.

Power on only 1 wire while the brake pedal is pressed means the switch is probably bad.

 

[mattyq17]

No power at either wire means the switch isn't getting power, not that it is bad.

Power on only 1 wire while the brake pedal is pressed means the switch is probably bad.

That make sense, looks like I have some more tracing to do.

Paul, I wire brushed the front and back side of the fuse block, put new fuses in and I have power to all spots front and back, so I know I have power to the fuse block.