Hello all, the previous owner of my 1923 Model T touring/pickup wired up two taillights, see pic:
Each light has a double filament bulb, one filament works as a stoplight and the other filament works as a turn signal. As a result, I have no full-time tail lights, and the license plate is only illuminated when I step on the brake. Can anyone share their way of getting tail lights, brake lights, license light, and turn signals on the back of their Model T?
I looked at one of the wiring diagrams on this forum and saw that the stock tail light is wired to terminal 4 at the firewall. I put my voltmeter on terminal 4 of my car and noticed that it only has power when the headlight switch is on "bright", it has no power on "dim", is that correct?
I went on online looking for ideas and saw a license plate frame that has some white LEDs for the license plate light and another set of red LEDs meant to work as a third brake light. I could wire both sets of LEDs to terminal 4, giving me a license light and a tail light when the headlights are on "bright".
I'm sure the LEDs are designed to work on 12 volts, does anyone know if they will work on 6 volts?
You need to either install separate lights for the turn signals or get a turn signal switch that can use the brake light filament for both the brake light and turn signal.
Sounds like a bad ground. Most if not all dual bulbs have one low intensity filament for tail, and high intensity for stop/signal.
Calif plates are reflective, so a cop would have to look very close for a lice light.
Thanks for the tips, everybody!
Missouri license plates are also reflective.
I decided to buy the license plate frame with the LEDs, I'll let you all know how it turns out.
Any comments on the tail light terminal 4 only having power when the headlights are on "bright"?
Well, I got the LED license frame in the mail today, it came with no instructions, so I had to experiment to find the correct wire assignments. The first thing I did was cut off the lower part of the frame to make it less bulky. Then, I tried hooking it up to a 6 volt battery, no go. However, the LEDs light up quite brightly on 9 volts, so I'm going to wire them up to a 9V battery and a switch for now. With the low current draw of the LEDs, a single 9V battery should last for hours if not days. Here are some pics with the LEDs running on the 9V battery:
As far as the tail light working on bright only, it could either be a bad switch or the switch is wired incorrectly. There should be a separate terminal on the back of the switch marked "TAIL". If not marked, use the photo below to help locate the correct terminal.
Thanks for the tip, I'll take a look at the switch and wiring. I'm somewhat suspicious of the switch, because I sometimes have to "jiggle" it to get the headlights to come on the "bright" setting.
Mark...I had the same issue with the switch on my '20 Runabout. Put in a new one, and voila...problem solved. Then put in a new wire loom from the switch to the firewall, and voila again...the headlights are now BRIGHTER, and all the problems I've been having with the brake light have suddenly disappeared.
I mounted the LED license frame (just the upper part, I cut off the lower part) with its 9V battery and switch on the car, here is a pic I just took tonight showing what it looks like. Not blinding, but at least now I have a working tail light and license light.
I'm going to investigate what kind of aftermarket turn signal switch I have and how it is wired; like Donald said earlier, it seems like the brake light filament should be able to do double duty as a brake light and turn signal, freeing up the other filament for tail lights.
In order to have the brake light and turn signal power the same filament of a bulb requires the use of a 7-wire turn signal controller, such as the 900 series Signal-Stat. It's really the best way to go, as the second, dimmer, filament of the bulb is then used as a marker light. I did this on both my T and my A. These 7 wire units are used in all heavy trucks from the late 70's and back, and can be bought used at truck junk yards for 5 bucks, with a great "old patina" to them, in either black or chrome.
I just checked my turn signal unit and it is a Signal Stat 900. Sounds like I need to add a re-wiring job to my winter project list. I found a Texas T wiring diagram for a 7-wire turn signal, it's a .pdf file and too big to post here, does anyone have anything better?
Oh boy, this is embarrassing, I must have been having a senior moment (Steve, it must be catching!).
I went back out to the car this morning to check the wiring again, turned the headlights to "bright", and guess what? My original tail lights and license light work! The only thing I can figure is that I must have had the light switch on "dim" when I checked the tail lights the first time. I also verified that the brake lights and turn signals work as they should, so the Signal Stat 900 is wired correctly.
So, after all that work, I removed the LED license frame with its switch and 9V battery. I'm going to hang onto it just in case I need it for another car or decide to put it back on the T some day. Here's a pic, altogether it's a pretty compact package:
The schematic for a 7 wire system here http://www.texastparts.com/mm5/manuals/T7669-T7.pdf is pretty good for lights except the power source for the brake light circuit and turn signals should come from the same point as the generator connection on the firewall.
My '26 Touring has single pole connectors in the tail lights, so when the ignoramus at the DMV insisted I have brake lights, I put in bigger single filament bulbs and connected a variable resistor, I happened to have, in the circuit. Then I connected a switch that bypassed the resistor when I depressed the brake pedal. For turn signals I found a pair of semaphores.
Ingenious solution for using single filament lights for tail and brake lights, well done!
If you are using 6V, you can convert your old single contact sockets to double contacts pretty easily.
You can get a double contact "lamp socket wire lead" from a parts store, Napa # 78107, or Dorman # 85801. This is the little fiber disc with the contacts inside the socket. It has a little tab on the side that usually fits in a slot to keep it from rotating. You can file it off, or cut a slot in your socket and use the tab. Also get some 1158 bulbs. These are the 6V double filament stop / tail lamps. They will work in your old sockets because unlike the 12V bulbs, the little retaining pins are at the same height on each side of the base just like the single filament bulb.
If you file the tab off of the disc, you have to work a little to keep the contacts lined up with the ones on the bulb, but after the bulb is in, they usually stay in place. Just make sure that your bulb is in correctly so that the bright filament is the brake light.
Not all parts stores stock 6V lights anymore, so you might have to order a box of 10.
If you want to convert to 12V lights, you can get complete sockets with the uneven pin slots for 1157 bulbs, but you will have to modify your tail light housings to install them.
Here's what I did when I built my new box. Not too fancy but very cost effective.
With 3 rear light threads going on, I posted to the wrong one. This was meant for the gent who wanted to know about installing tail lights. Oh well.
That's the way I was trying to express to John for mounting his perhaps, as it is an easy to access area.
Thanks for the kind words. I was 19 then, and a lot smarter than I am today. ;-)
I need some opinions as to which brake light switch works best. I see Lang's offers several options. 3158HD is a kit that mounts to the back of the transmission. Others mount to the bendix cover and some mount to the frame rail. I'm leaning toward the kit. Any suggestions as to which one is best? No show car here. Thanks Frank
I use a Yahama universal brake light switch. Spring loaded pull on to activate and has a spring on the pull part of the switch so you do not pull out the "innards" when hooked to the brake pedal.
I used the Fun Projects brake light switch kit on my 26. Excellent.
The heavy duty kit that Lang sells is the same one that Dave Young is talking about. We make it so if you have any questions - ask away.
I thought that one looked best. Never expected to meet the manufacturer! Thanks guys!
I've used John's brake light switch and can vouch for its quality. It works great!