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

Does anyone have any better wiring diagram on the turn signals than what is in the shop manual? I am getting very weak rear turn signals because of not getting the full 6 volt signal. I jumpered the stop switch and then measured the voltage both at the stop switch and at a rear bulb. I was only getting 4 volts so dropping two volts somewhere!! It appears that the stop switch gets its voltage from the rear of the headlight switch. And that could be a can of worms. Since I am not going through the ignition switch that isn't the problem. Does anyone have any suggestions? Not sure what to check next.

I believe but will not swear to it that the 42 turn signal circuit is identical to the 46 - 7 circuit and similar to the 48. It is hard to tell from the 42 diagram but if you have two bulbs in the rear, a dual filament for brakes and tail lights and a separate bulb for turn signals, then it will be. If that is the case here is an extraction of the postwar turn signal circuit and a photo of the 46-7 switch showing the contacts. I believe the 42 switch will be the same electrically although maybe slightly different physically to fit a different shroud.

Potential issues are a dirty switch, sockets, any grounds and inline connectors. Packards seem to be very prone to poor grounds developing at the park and tail light housings and that does seriously affect the various bulbs with results from no action at all to very erratic operation. The old thermal flashers are very dependent upon the correct resistance thru the wiring, bulb filaments to ground. That would be the first suggestion is ensure all the bolts or studs from housings that connect to sheetmetal and provide the grounds are clean and tight. Sockets that get wet can also have the phenolic plate that supports the contacts warp and develope a poor connection. The inline connectors -- particularly those exposed to any moisture -- were known to oxidize even in Packards day so they could also be a source of high resistance and low voltage.

Circuit function: When switch is moved it connects bulbs from the R or L side to the flasher to start the heater and activate the bimetal for the flash cycle. When the bimetal makes contact flasher provides 6v output at L and at the same time both indicator lights get power thru a resistor from the contact which is activated like a relay and connected to P. Note that the indicator lights have their other wire connected to the opposite side signal bulbs. This is to have the ground for the indicator bulbs be provided by going to ground thru the inactive filaments on the off side so only one indicator light is on at a time. As soon as the bimetal makes the solid connection it effectively bypasses the heater by providing the same voltage to both sides. This results in the heater cooling and as it cools the bimetal unbends to stop the voltage and action to extinguish the lights. Since the signal switch is still connected the heater starts again and cycle repeats until the switch is turned off.

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  46-7 turn signal extraction.jpg (55.62 KB)

Howard is right 100%. I periodically use a wood skewer and fine steel wool to clean the bulb sockets, grooves, contacts and bulbs. Do one and see if there’s a difference.

You guys are very brave to answer my question. No I have more than the usual going on. One thing I wonder if you can clear up for me. In the diagram, at the rear, stop & dir signal light area, it shows green wires going the the stop light. It also shows wires going to the signal lights.
On most cars that I have worked on, they use a dual element bulb as does mine. The one element is brighter and used for the stop & dir signals. But in the wiring diagram they show one wire going to the stop ckt and another two wires going to the turn signal elements which is one and the same with the stop ckt is it not? What am I missing here and why am I confused???

To have the brake light and turn signal share the same filament there needs to be some way of interrupting the constant brake light feed to the side that is flashing. Without doing that the flashing could not be seen since the constant brake light on voltage would override the flash and keep the light lit.

Prior to the 23rd series Packard did not offer that feature. Brake and tail lights used a single bulb with the bright filament being for brakes. They chose to use a simple 3 wire turn signal switch that could only direct the turn signal flash to a side and light both bulbs at once. Since brakes already were at the rear bulb powering the bright filament that meant a separate bulb was needed in the rear for the signals. With the introduction of the 23d series 49s they went to a turn signal switch with 6 wires that was capable of connecting the 4 turn signal filaments independently as well as interrupting and directing the brake light signal to the side opposite the bulb needed for flashing. With that switch change they were able to use the same rear bulb filament for both functions.

The factory 42 diagram is a bit lame and leads to confusion in that it only shows 3 wires going into the single rear housing. The A.E.A diagram that can be downloaded from the PAC site does show the two bulbs in the rear housing but the print quality is rather poor in trying to read the wire color labels.

For clarification of the difference in turn signal circuits and switches here is the 49 to 56 extracted diagram. You can compare it to the prewar to 46-7 circuit. With the exception of 48s having only a single dash indicator light, those models also had the same basic 3 wire turn signal switch so needed the separate rear bulb as used in the earlier years.

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My auto is a model 2055 & was called an invalid sedan. Because of the war this car was thrown together and is not standard. It does not have the regular 1942 tail-light. It has the long slender type that were from a '41 or earlier Packard and has only one two element bulb in it. The car did not have a steering wheel turn signal when I got it. Could not find an original but got one that was similar and installed it several years ago. It did have a two terminal flasher unit wired into the car however but no turn signal. I left that as it was and as you say about the brake signal. I installed two diodes that would lite the two rear turn-signal lamps together but would be out of the circuit when the turn signal was on. Yes I have a mess on my hands and with all the original old wiring I hate to get too involved. But it did work once thus can't give up.

I suspect the only diagrams or advice the forum can provide would be for the stock setup. If you have an aftermarket unit and a car that might have been built and not equipped like the production models then it would be anyone's guess as to what you have or what is going on. If you can identify the turn signal brand or switch setup possibly some diagrams for that unit might surface but that is only a guess. You may need to open it up to see what is inside and how it connects to sort of reverse engineer your own diagram.

The 1942 wiring diagram is a mess. It shows a flasher all right but is not showing it correctly. If you look at it, both indicator lights R&L are connected to the same terminal. Now you know this cant be right or maybe I do not understand the circuit. Certainly not what I have or had originally.
My flasher unit is getting it's voltage from the same circuit as the heater ckt. But I can't even find the heater on the diagram!!! I am wondering if I should wire the flasher to a little different source.
Did Packard ever show the heater wiring anywhere in '42?

It shows a flasher all right but is not showing it correctly. If you look at it, both indicator lights R&L are connected to the same terminal.

The factory diagram is correct. Say you want to flash the L signals. When the lever is moved and the flasher starts the L side flashing, both indicator lights get power from P on the flasher at the same time. Notice the wire from the other side of the L indicator bulb. If the bulbs were connected so the left and the right indicator bulbs were connected to their respective sides then you would have the same power to both sides of the indicator bulbs at the same time and no light. With the other wire from the L indicator bulb connected to the R side lights, when the flasher puts power to the indicator bulbs it goes thru that filament and over to the right side which is just sitting there not connected to anything but ground thru the filaments of the outside bulbs. The L indicator bulb gets a ground by going thru the filaments of the R side outside bulbs and will light while the R side bulb sees the same 6v from the flasher P terminal on one side but also 6v coming from the flashing L side on the other wire so with no ground it cannot light.


Turn signal power is shown coming from battery side terminal on the back of the gas gauge. That is the terminal that was fed straight from the ign switch and Packard frequently used it to provide power to accessories because it was easier to get to than most ign switches. Connecting directly to the GA terminal of ign switch was done whenever it was easier.

Heaters were an accessory and Packard generally did not include many accessories on regular diagrams until 48 or so. Some earlier diagrams might have an extra single illustration of the dash showing a few common accessories. I found one diagram for the Clippers that showed the Deluxe heater, radio, fog, spot light and reverse light.

Howard I really appreciate you trying to help me. I am completely lost right now and sure could use your help. Not only am I not getting full voltage to me turn signals, but I find out that I am not getting any voltage to my rear running or park lights. The front parking lights are working fine. On the diagram if I go to where the interconnections are just past the front fender under the car on the inside chassis rail, I am not getting any voltage there!!! I should be getting voltage on the first notch of the headlight switch. But if I look at the diagram wire 45D & 45C go to the front park lights. There are wires numbered 45B & 45C that I would think would be for the rear lights. But I do not get any voltage there at all. But what gets me about the diagram, is where are these wires connected to the Lighting Switch? They are not shown or they switch to different numbers which makes tracing impossible. Help!!