Packard Forum Index » Pre-War (1899-1942)

Okay, over the summer I took the transmission down out of Sophie, my '29 Club Sedan because the clutch was beyond shot and the pressure plate wasn't much better. Dropped the tranny, sent the clutch and pressure plate off to Ft. Wayne Clutch (they did a superb job and reasonable price), polished the flywheel until it looks like a shiny new silver dollar and cleaned all the sludge out of the gearbox. Put it all back together (took 3 months) and it's running and driving better now than it has since I bought it back in 2020 - BUT, one maddening problem, my brake lights aren't working.

Brake lights worked before the operation. I realized I had the plug on the side switch 180 degrees out of sync when my reverse lights were coming on when I turned my headlights on. Switched that connector around, tail lights and reverse lights work correctly now, but I cannot get the brake lights to work. There is an adjuster screw on the front of that switch that seems to connect with a plunger coming from the switch. No matter what I do with that screw or where it hits or doesn't hit, nothing lights up when I push the brake pedal. And I doing something drastically wrong with that screw or is there something else I should be looking for? Thanks much guys!

First of all just disconnect the brake wires and attach an ohmmeter across the leads to see if the circuit ever closes.

If that's fine, then you must have a broken or corroded connection on one of those wires.

Wiring diagram shows brake lights get power from the same terminal that feeds the main lighting switch and is coming directly from the main fuse block. Unless there is a wiring problem or mistake in a connection at the main lighting switch power should be present on one of the wires at the brake light switch all the time. Use a voltmeter to verity power is present.

If power is present I would then disconnect the battery or if you can carefully disconnect the wires from the brake switch with the battery connected, then follow HPH's suggestion of using an ohmmeter across the switch to see if it is closing. If not, try adjusting the screw until switch works or else start looking for a problem in the switch.

If power is present all the time you could also use a jumper to temporarily bypass the brake switch to see if the tail light works when connected wire to wire and thus rule out any issues with that part of the wire, bulb, or socket.

This is the switch and adjusting screw in question. The reverse light comes off the top of the transmission but is somehow involved with the power supply to this switch, as when I first started it back up, the reverse lights stayed lit whenever the headlights were on. I switched this plug around and the reverse lights and tail lights now work correctly.Im thinking the issue has to do with the black adjuster screw which engages a brass or copper plunger at the side of the switch (shown disengaged here). You depress the brake pedal, that screw moves away from the plunger. The silver coated wires are encased in a block of solid solid rubber which simply has contacts at the end to touch the two contacts in the switch. Car doesn't have a fuse box, only has one fuse! I could rest the two contacts inside the switch I suppose.

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If you have a connection to the back up light switch, there must be an additional drawing because the 29 drawing I have and an almost identical 30 drawing shows the brake light switch fed from the same place and that being the wire coming from the fuse. The 29 and 30 drawing shows the connection originating at a lighting switch terminal and a 28 drawing is almost the same but shows a splice in the wire from the vibrating circuit breaker feeding the brake switch. None of the drawings show anything with the brake light being connected in any way to the back up light switch. The back up light bulb on all 3 drawings is powered from the tail light feed and the switch only provides ground to the bulb when active.

Here are the 29 and 30 drawings I have and if you have something different, if possible could you post it. My 28 drawing is not the best quality so I won't post that one unless someone wants it. The 29 AEA drawing is one I downloaded from the PAC site before it was locked down. Don't know if it is still accessible for nonmembers but if you are a member you might be able to get a better copy or might find more versions.

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The diagrams are correct. Everything gets its juice through the lighting switch on the steering wheel. I think the problem lies in the adjusting screw, which I'll mess with more this weekend to see if I can get it worked out. Look on pages 47 and 48 of the 1929 Service manual dealing with changing or adjusting the stop lamp switch. In the typical useless manner that those manuals describe everything, it's like "Step 1: Replace Switch" then, "Step Two: Adjust switch until pedal is 1-1/2" off the floor board." Which is a bit nonsensical when it comes to a '29 Packard - the brake pedal doesn't go through the floor board, it goes through the toe board, which they're usually adamant at calling such. Also, if you can get that brake pedal to go to within 1-1/2" of that toe board, you'd be pressing the brakes through the drums! With the brakes fully engaged and locked, the pedal is a little over halfway down and always has been. And again, the lights worked fine before I took the tranny out last June. It's gotta' be something with that crazy screw. Thanks much and I'll keep you posted as to what the gremlin is!

Not knowing much about those years, can't offer any hints but hope it does turn out to be a simple adjustment. Am curious what the screw moves to activate the switch. I don't see anything obvious such as a plunger or lever for the screw to hit in the photo you posted so it must be hidden. Any chance something was pushed aside, bent, or has fallen out during the transmission R & R?

In looking at another manual, am wondering if they used the same switch as the 28 six models. If so, from the adjustment procedure in the 28 owners manual saying if the screw is out too far the light is continuous, and too much in will damage the switch it sounds as if the switch can take only a certain amount of travel. Once the pedal starts to move downward, then within approximately 1 1/4 inches of travel the screw has moved the switch enough to let it close and light the bulb. It might be worth checking to see exactly what type switch is used and if the bulb or switch are both still good. Is there any way to activate the switch with fingers or some kind of external makeshift plunger just to see if the switch will close and bulb light without moving the pedal?

Just a note from experience with old wire...When you moved wire around during the clutch removal...one of the wires may have separated inside the cover...check each wire for continunity...then clean all the connections and make sure the ends are still on tight. If you can take the switch apart...perhaps it has 90 or so years of dust in it and the contacts inside are dirty like distributor points...and need to be cleaned and or polished...Ernie in Arizona