bigvince | -- 08-15-2011 @ 2:41 PM |
I just completed the restoration on my 48 Woodie wagon including all new wiring. When I step on the brake, both brake lights illuminate - and so do the instrument panel lights. What did I do wrong and what do I look for? Mechanical I can handle - electrical wiring is not my area of expertise. Thanks!
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MG | -- 08-15-2011 @ 3:55 PM |
Somehow you've made a common connection point of the brake and dash light circuits through the brake switch. If your new wiring came as a wiring kit, there should be a schematic drawing you can refer to and double check your connections based on the color code of the wires. If you used a non-standard wiring scheme, trace the wiring at the brake light switch - one side to battery and the other side to the tail lights. Should be just two wires on the brake switch. You must isolate the two circuits (dash and brake) from one another. I can visualize the problem you have but it's hard to explain this simple fix. Do the dash lights come on as normal when you turn the headlights on with your foot off the brake? This message was edited by MG on 8-15-11 @ 4:11 PM
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deluxe40 | -- 08-15-2011 @ 5:01 PM |
I'm thinking you have one of the brake light wires connected to a tail light. The tail lights are in common with the dash lights, so If a tail light gets power, the dash lights will be lit. Problem is I can't figure out how a tail light can be connected to the brake light switch and still be connected to the tail light wire. Still thinking... This message was edited by deluxe40 on 8-15-11 @ 5:11 PM
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ford38v8 | -- 08-15-2011 @ 5:08 PM |
DeLuxe40, me thinks you have acquired this knowledge by way of personal experience. What say you? Alan
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deluxe40 | -- 08-15-2011 @ 5:15 PM |
Although I have lots of personal experience hooking things up backwards, I'm just trying to figure out how a person could plug in a new loom to get this result. I made a drawing and thought I had it, but now I'm not so sure. How can that tail light be connected to BOTH the master cylinder and the light switch (and the dash lights) at the same time? OK, here's a theory. The new wiring loom also works on a sedan or something with a separate license plate light. So, the wire that is supposed to connect to the passenger side brake light gets connected instead to the the connector on the loom that is supposed to power a license plate light. So power from the brake switch goes back through the loom to the light switch on the dash where it connects to the dash lights. This message was edited by deluxe40 on 8-15-11 @ 6:01 PM
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shogun1940 | -- 08-15-2011 @ 5:49 PM |
I have the same problem on a 48 I think who ever wired the car has the brake and tailights reversed, its a rats nest under mine in the back. I think this is the problem because the tail lights are real bright, I hope its that easy
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trjford8 | -- 08-15-2011 @ 8:21 PM |
I hate to beat this issue to death, but if the tailamps are not properly grounded the brake lamps will feed back through the tailamps with a poor or no ground. On a woodie it is critical to ground the tailmp housings. The feedback can cause the dash lamps to illuminate.
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deluxe40 | -- 08-16-2011 @ 10:28 AM |
Tom, thanks for the explanation of the ground feedback possibility. It makes sense and didn't occur to me. It will be interesting to learn what bigvince finds.
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bigvince | -- 08-16-2011 @ 5:41 PM |
Guys, Many thanks for all the suggestions. Evrything is hooked up right. I disconnected the tail light/license plate side (left) and the right brake light still works and no instrument panel lights come on when I sep on the brake. That's good. I'm going to try grounding the left side again and check everything there. I HATE ELECTRICAL!!!
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TomO | -- 08-17-2011 @ 7:00 AM |
Bigvince, Trying to isolate a ground loop by disconnecting things can lead to false indications. The 2 stoplights draw enough current to light the dash bulbs, but 1 stoplight may not. I would use a jumper wire from the tail light housing to a good ground like the bumper arms or the chassis. If that resolves your problem, the use a ohm meter or continuity checker to check that both tail light housings are grounded. Tom
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supereal | -- 08-17-2011 @ 8:38 AM |
Due to the construction, woodies present more than average grounding problems. Extending separate ground wires is almost always required. Otherwise, two filament bulbs "find" ground thru the other side when the socket is poorly grounded. This occurs in non wood bodies, of course, but is a special problem in station wagons.
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42wagon | -- 08-17-2011 @ 9:45 AM |
While I agree that a good ground is essential woodie taillights should not present any more problem than other lights. Why? Well the taillights have a metal arm for the mechanism that makes the lights stay vertical no matter what position the tailgate is in. That arm is bolted directly to the metal floor that in turn is welded to the cowl where the battery ground strap is bolted. Therefore a direct ground path from the taillight to the battery exists despite the fact that the taillight is bolted to a wood tailgate.
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supereal | -- 08-17-2011 @ 11:52 AM |
It should be that easy, but it is likely the joints in the arm are rusty or dirty, etc, or the socket isn't making good contact with the sh*ll of the light. The number one electrical problem with all old cars is poor grounds. When the vehicles were newer, using the body as a common ground worked well. After decades, not so good. That is exactly why we take the time to install a ground wire to all lights. At six volts, it only takes a 1 ohm resistance at 6 amps to kill the power. A bit of dirt, old paint, or rust can do it. We use a special electrical grease on most connections to lessen problems caused by oxidization, and solder all of the bullet connections, a constant source of trouble in old Fords.
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Dolman | -- 08-17-2011 @ 1:00 PM |
I agree with Super. If an electrical connection is intended to be permanent and it can be soldered, solder it and slip heat shrink tubing over it. Alan had mentioned using dielectric grease on all connections and I assume he meant on the outside. It is good for corrosion resistance and won't eat rubber, but should only be applied AFTER making a firm connection of two clean surfaces. Never put it between the surfaces or you run the risk of making a resistor or an open circuit. Some would say that the pressure of making the connection would squeeze the grease out, but I wouldn't count on that happening.
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Stroker | -- 08-17-2011 @ 1:25 PM |
Even the older wagons that have the tail light mounted on the D pillar have bolts that attach to the lower tail-gate hinge/spreader bar, which is bolted to the floor pan. The dome light however, must have a ground wire. Living in the "Rust Belt" I've fought lighting issues on all our equipment. Dedicated ground wires are almost essential for reliable lighting. My favorite method of splicing, or attaching terminal ends to wires is to Solder, rather than crimp. As for sealing moisture out, I've had good luck coating the exterior of the junction with "Liquid Electrical Tape", and then applying heat shrink tubing before the liquid tape completely cures, forcing it to squeeze out of the ends of the tubing.
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