tail light, speed nut, grounding question

[Tim D.]

I am having trouble getting a good ground on my 64 convertible w/back-up lights. After reading the archives, I know that a poor ground is what is causing one of my tail lights to light twice as bright as the other when I step on the brake (parking lights off). When the the parking lights are on, and I apply the brakes, one light goes out. I tested all of this with a separated ground wire to the frame and it all works perfectly.

The problem I'm having is I can't seem to get the speed nuts to tighten enough to get a good solid ground.

Speed nut questions:

1. Which way do the speed nuts install on the tail lights?
a. as you would put a hat on your head OR
b. as you would put a hat on your head upside down
( a photo would be GREAT)!

2. Should any washers be installed on the tail light studs before and/or
after the ground wire and speed nut, if so, how many and in what
order? My AIM doesn't show any washers, but it seems like they
may be needed to make metal to metal contact and draw speed nuts
tight.

3. Are these winged speed nuts or "regular" speed nuts. Also, what size
is correct?

4. Do I need to buy a winged speed nut installation tool?

5. It was suggested in the archives that one needs to first install the
speed nuts on the stud "off of the car" to get it pre-threaded. It
was also mentioned the "chrome" plating must be stripped from the
mounting stud before trying to thread the speed nut because the
speed nut's metal is not as hard as the chromed stud. Is this true?

Any thoughts, photos, info would be MUCH appreciated. I am almost embarressed asking these questions. It shouldn't be this difficult, right?

As always thanks in advance for everyone's help and knowlege,

Tim (50796)

[William C.]

Re: tail light, speed nut, grounding question

The speed nut goes on like a hat with the brim closest to the back of the housing. Properly used speed nuts will cut thru the plating easily. If they are not firmly tight on the stud, then remove them and "gently" whck them with a hammer to adjust the size. Also, are you using new wiring or old? If old, using a dremel tool with a small wire brush attached to clean off the mounting surface on the ring termainal might be a good step.

[Tim D.]

Re: tail light, speed nut, grounding question

Bill, thanks for your reply. All wiring is new as are the tail lights, speed nuts etc. I used my dremel and cleaned everything last night just in case.

So...the brim of the "hat" (speed nut) will make contact with the metal "neck" of the wiring eyelet near where the wire is crimped into the eyelet and no washers are used?

I am using a 7/16 end wrench and can't seem to get the speed nuts to tighten down with enough force to create a solid ground. They only go on to the stud a short distance. So, I tried using washers to take up the slack. Not working well!!!!!


Should I remove the tail lights and run the speed nuts on the stud while they are out of the car and then reinstall them....thinking if the stud is pre-theaded it will tighten down better while in the car?

Thanks,

Tim

[David C.]

Re: tail light, speed nut, grounding question

According to the first couple pages in the AIM, sheet A5, stamped nuts go with the "open" end up, and there is a caution warning that describes open end down torque problems. Not sure if this apples to tailamps or not.

[Tim D.]

Re: tail light, speed nut, grounding question

David, I read the same thing in my AIM and that is part of my confusion. I am not sure if this applies to all speed nuts or the so called winged speed nut (not sure what this is or where it is used). I'm also confused about the winged speed nut installation tool that Paragon and others sell.

Also, if a regular speed nut is installed with the open end up like the AIM states, how do you tighten it? You can't get a wrench under it to get to the nut/hex and you can't use an allen wrench from the top to go inside of the nut/hex because as you tighten it, the stud will come through and interfere with the allen wrench.

This shouldn't be this hard but I have a knack for making things more difficult than they need to be. Tim

[John H.]

Re: tail light, speed nut, grounding question

I am having trouble getting a good ground on my 64 convertible w/back-up lights. After reading the archives, I know that a poor ground is what is causing one of my tail lights to light twice as bright as the other when I step on the brake (parking lights off). When the the parking lights are on, and I apply the brakes, one light goes out. I tested all of this with a separated ground wire to the frame and it all works perfectly.

The problem I'm having is I can't seem to get the speed nuts to tighten enough to get a good solid ground.

Tim -

Doesn't sound like a ground issue to me, as both lights are working, so both are grounded. Make sure the plastic connectors on the harness are oriented correctly where the "tits" on the plastic engage the slots in the bulb socket; they're designed to engage only one way, but there's very little angular difference between "right" and "wrong", and it's easy to mis-orient them, making the two filament contacts engage the bulb contacts backwards.

Just put the ground wire ring terminals on the lamp studs and tighten the ordinary stamped hex speed nuts until they bottom out. Someone posted the photo below a year or so back that shows what they look like.

[Paul J.]

Re: tail light, speed nut, grounding question

Tim and David,

Notice the orientation of the speed nut in John's picture. That is the only way that I've seen it done and I believe that it is the correct way, like Bill said. The other way does'nt make sense.

Paul

[William C.]

Re: tail light, speed nut, grounding question

Note that as in the picture, enough pressure is used to seat the nuts against the housing and terminal with reasonable tension.

[Tim D.]

Re: tail light, speed nut, grounding question

Thanks guys. All advice is appreciated. The photo definitely helped.

John, I will check the orientation of the "tits" etc. ...but when I ran a separate jumper wire from the tail light speed nut to the muffler bolt (ground) all problems went away and everything worked properly.

Here is what is happening (64 w/ back-up lights)......with all lights off, when I apply the brakes, both brake lights come on, but the driver's side is twice as bright as the passenger side. If I use a jumper wire and ground from bottom speed nut to muffler bolt, the passenger brake light becomes as bright as the driver's brake light as "normal".

With the parking lights on..... when I apply the brakes the passenger light goes out. If I connect the jumper wire as previously mentioned, all works perfectly.

I'm going to check the orientation of the "tits" now.

Tim

[William C.]

Re: tail light, speed nut, grounding question

Tim, I'd check the integrity of the ground wire on the side you are having trouble with. It runs to a splice in the harness. Your problem sounds a lot like just a bad ground on one side. One other thing to check is the proper orientation of the bulbs in the sockets. The park/turn lamp bulbs can sometimes be inserted backwards in the socket, and that will result in similar symptoms.

[Tim D.]

Re: tail light, speed nut, grounding question

Bill and John, sounds good. I'm out in the garage checking all suggestions. I will get back with results ASAP. Thanks so much. Tim

[Tim D.]

Re: tail light, speed nut, grounding question

Bill, David, John and Paul,

Great news....problem solved! I love this site....you guys are the best! I really appreciate everyone's knowlege and willingness to help.

Here is what I found....About a year ago, I asked my painter to install my rear wiring harness and rear lights while the body was still off of the chassis. I discovered that he used the wrong size speed nuts. They would not thread onto the tail lamp studs more than approximately 1/4 inch, therefore, he stacked washers to take up the slack. This Bubba job only allowed the whole assembly to be snugged and therefore, the ground wires were not tight and not making a solid connection. Now that I look back, I remember thinking his installation didn't look right. I knew the AIM didn't call for washers.

Solution....I took everyone's advice and performed the following:
I removed all four lights from the car. I found the correct speed nuts and threaded them onto the male studs out of the car. They cut new threads very easily. Since they were the correct size speed nuts, they bottomed out nicely and the lights fit really snug to the body. The grounds are now really tight. I removed all washers, cleaned all contact points with my dremel and/or by hand. Verified the correct orientation of the plastic "tits" in the slots (John, I see what you meant). I also verified that each tail light and back-up light had the correct bulb and also that the bulb was installed correctly. Everything works as it should!

Thanks a million!
Tim (50796)