Wiring Woes

[Dakota Boy]

Taillights, headlights, and power windows.

Started in the back of the car with the tail lights... cuz I thought that would be the easiest. Wrong. I dont know if my stop/brake light switch is functioning when I press the brake. I dont know if my turn signal lever is functioning. I cant see up behind the instrument panel to even see if that stuff is plugged in or not.

I'm about ready to pull the instrument panel out and start tracing things from there.

[JohnG]

Headlights/tailights
in the Technical Resources Library I have an article showing what all the connections to the headlight switch do, for example http://users.wpi.edu/~goulet/TBird/H...%20Repairs.htm

Do you have a multimeter?? That will help alot. Shop manual with wiring diagrams?


Brakelights: those have been discussed a number of times - try the Search and see what you come up with. There are directions for isolating the problem.

Let me know what you find.

best
John

[Dakota Boy]

yes, I have a meter, and wiring diagram (from this site; I made like 10 copies, then used a highlighter to mark the circuits on thier own separate pages)

This site is great: I can now test the the brake light switch on the master cylinder. I am curious how it functions though. what inside the master cylinder causes the circuit to close and the lights to come on?

[Guest]

Dakota Boy,
The switch is on the brake booster under the hood. It is about the size of a quarter and has two wires going to it. With your meter on OHMS check meter wires by touching them together. Then take wires off brake switch and check by touching one to where each wire was. Circuit should be open. No have someone to step on brake pedal and check again. You should get reading when brake pedal is pressed. You can also pull the wires off and take a small piece of wire and insert in the terminals of each wire. Press brake pedal and see if brake lights work. Keep us informed!!!
Richard D. Hord

[JohnG]

I have never cut one open (although I intend to one of these days) but there seems to be a membrane between the fluid and the electrical part. The pressure flexes the membrane which in turn closes a switch, completing a circuit and making your lights come On.

Sometime in the early 60s they went to a mechanical switch on the brake pedal...

By comparison, you have an oil pressure switch down by the oil filter which is normally On in the absence of pressure and then goes Off as soon as there is pressure, hence the light on your dash.

[Dakota Boy]

I am 99% positive in have all the wires in the trunk hooked up correctly now, but the brake lights are on all the time.

And it doesnt seem to matter if the wires to the brake light switch are hooked up or not. So the brake light filaments are getting power from somewhere.

Where is the "directional switch" located (all the turn signal wires run to this)? one of the green wires at the brake light switch is supposed to terminate there.....

And WHY in the world wont my brand new license plate bulbs light up, even when I have like 11.5 volts at the sockets?
Thats just plain weird...

[Guest]

Hey Dakota Boy,
Are you sure its brake lights or like the headlight switch is on?
The turn signal switch is in the steering column. As far as license plate bulb check for ground, these old cars are bad about corrosion and or paint build up under grounds.
Richard D. Hord

[Coral]

Hey Greg...Im going to get in touch with my uncle and see if he can't refer us to someone or help out himself... they are in Muskego so not too far away...

[Dakota Boy]

oh, that would be awesome!

I feel like a blind caveman trying to invent fire at this point. I'm sure it's all simple stuff, I just am way too "green" with this wiring business

[Coral]

I can commiserate... when I found rat chewed wires under Coral's rear seat and started going through them, taping them up it was like a spider web of confusion... and I have done such things as building a new PC tower, installing a ceiling fan in my house, running gas line for the stove, wired a water pump... and yet, the wiring harness on a car makes me shudder in fear...

[JohnG]

If you get out the wiring diagram and follow the brake light wiring, I believe you will see it goes to the directional switch in the steering column and THEN to the brakes.

The reason is this: the brakes and directionals use the same bulb. So if you foot is on the brake AND you have the directional on then you dont want that bulb On all the time but rather flashing. So I think one of the functions of the directional switch is to disable the voltage to the brake light and instead enable the flashing voltage of the directional

Follow the wiring in the diagram and see where it leads you...


Having good grounds is always important and never should be taken for granted due to paint and rust. When testing, have a long jumper wire you can run right to the Negative post of the battery and to what you are working on so you can temporarily eliminate that issue.

[Howard Prout]

The reason is this: the brakes and directionals use the same bulb. So if you foot is on the brake AND you have the directional on then you dont want that bulb On all the time but rather flashing. So I think one of the functions of the directional switch is to disable the voltage to the brake light and instead enable the flashing voltage of the directional.

John, I don't know about the '58s but what you say is only partly true for '59s because for the 59s in the two outer tail lights units, the brake and turn signal share the same bulb filament but in the inner tail light units, the bright filament is for brake light only. More simply put, there are four brake lights but only two of these are also signal lights.

[JohnG]

Hey Howard - Thanks!!

I did not know that.. I lazily assumed that 58 and 59 were identical and '60 was the odd one (6 tail lights).

That makes the '59 a bit safer then, since you are doubling the brake lights. Easy to change and a good idea.

Sometime we ought to get some knowledgeable people like you to pool what they have and produce a 3 column table listing as many differences between the 3 years as possible.

In the brake light area, I have long forgotten the details, but at one point there was a relay in the left side of the trunk for brake lights. Maybe '58 for all I recall. I think this appeared in a thread someplace. Now if you didnt know that and the relay died, you could go to a heckuva lot of trouble....

john

[YellowRose]

Wiring Woes

If I understand this right, the '58's and '59's had a brake relay in the drives side trunk area behind the trunk coverings. Go to this post and you will see pictures of that relay and posts regarding it. I don't think the '60's had it, but the '58's and '59's did, I think. When I get to my trunk area, I am going to look for this sucker and see if I have one. It is hiding behind one of the trunk panels on the left side if it is there.

http://www.squarebirds.org/vbulletin/showthread.php?t=5128&highlight=brake+light+relay&page=5

[dgs]

Sometime in the early 60s they went to a mechanical switch on the brake pedal...

Really? When i bought my new brake switch from NAPA and expressed my surprise at them having one, he said Ford used the same switch on a lot of cars up through the mid 80's! Maybe the T'birds switched in the 60's, other Fords kept it longer.