39 Buick flasher wiring question

[buick looks fine for 39]

Hey guys,

After installing a new wiring harness in my 39 Buick I'm down to finishing my stock direction signals. I have a nos 39 Buick flasher with the part number imprinted on it. According to the instructions provided from the company who made my replacement harness there is supposed to be an "x" on one terminal of the flasher which is the hot side, and an "l" next to the other terminal which is the load side. My correct 39 Buick flasher has nothing marked on the flasher designating which side is load or which is hot. I have 5 correct  flashers taken out of 39 parts cars with

a short section of wiring intact and 3 are wired one way and 2 are wired the opposite way. Again there are no "x" "l" markings on any of my used flashers.   I guess it may not matter which way the flasher is wired but I'd hate to wire it wrong and burn out a rare new part. Is there a way to test a flasher safely to determine which terminal is hot and which terminal is the load side? I called the company who made my harness and talked to one of their technicians. He suggested I look up  flasher wiring for a 39 Buick on the internet which is less than helpful.

                                                                                                        Thanks

                                                                                                            Leif

[Jolly_John]

Hello, Leif. Good to see you continue to make progress on your '39 convertible. Here's what I can share regarding the flasher wiring.

 

I have several NOS (Tung-Sol brand) flashers for the '39. Both have the terminals identified with letters, as you've indicated in your post. My photos below will hopefully provide the info you need to get all three flasher terminals wired per the factory. Take care. John

 

 

 

[buick looks fine for 39]

Thanks John, I really appreciate the reply. What I'm Installing is a factory flasher with 2 contacts, and it does not have letters anywhere on the flasher.

                                                                                             Thanks again

                                                                                                leif

  

[Jolly_John]

My pleasure, Leif.  It's been my understanding that the correct, original flasher for the '39 BUICK is a Tung-Sol P229D, a three contact unit. This flasher is the one I photographed above. The box indicates it is for operating two 6V, 21 C.P. bulbs (not counting the small turn signal indicator lamp on the shift lever). As shown, this flasher has three contacts. One for the 6V in (contact X), one for the load out, which connects to the switch on the shift lever (contact L), and the feed to the little green turn signal indicator on the shift lever (contact P). This seems like the perfect flasher for the 1939 BUICK turn signal set-up. 

 

Unfortunately, I don't have an original wiring diagram for the '39 handy. However, one would likely show if a two or three contact flasher was used by the factory.

 

Leif, If you feel a two contact flasher is correct, I certainly respect your thoughts, and understand your issue with the unmarked terminals on your flasher. If you do go with the two contact unit, where would you plan to make the connection for the shift lever turn signal indicator? I'm still hung up on the three contact flasher being the correct one vs. the two contact unit. But, of course I'm willing to listen and learn....I respect the depth of your knowledge about our "beloved" 1939 BUICK's! Best regards, John

 

 

Edited September 28, 2022 by Jolly_John (see edit history)

[neil morse]

While this may not be any help at all, the '41 definitely uses a three contact flasher like the one in the photos posted by John.  That's what it shows on the factory wiring diagram and that's what I have in my car.  Someone around here must have a wiring diagram for a '39.

[Bloo]

I don't know either, but I do know one thing.

 

If there is a little green turn signal indicator on the shift lever as Jolly John suggests, and if it is only one little green light, and that same little green light flashes for either side.....  There is no way that little green light is going to work without a 3 pin flasher.

Edited September 28, 2022 by Bloo (see edit history)

[Jolly_John]

Your assumption is correct, Bloo. The single green indicator light on the '39 shift lever flashes when either the left or right rear turn signal is activated. Since the turn signal switch (also on the shift lever) is not self-canceling, the small indicator light is to alert the driver that one of the turn signals is flashing. John

[buick looks fine for 39]

Hi guys, I apologize for not providing photos but my tried-and-true method for uploading photos crashed. The flasher for a 39 is one year only with the group number being 2.892-part number 1310666. The part number is stamped into the flasher. 40 and later flashers will work in a 39 and they do have 3 terminals, but the original flasher for 39 has 2 terminals with a mounting bracket spot welded to the base.  I have no qualms about using a later type of flasher but since I have a 39 flasher, I thought I'd use it. Since my flasher has no printed indication as to which side is hot and which side is load, I have a 50% chance of wiring it up wrong. In some applications where points are used in a system, applying current in the wrong direction will prematurely pit the contact points. I might be overthinking this and it may not make any difference, but I'd rather be safe than sorry.

 

                                                                                                                    Thanks guys

                                                                                                                         leif 

[buick looks fine for 39]

Maybe this will clear up some confusion, the hot lead to the flasher is piggybacked with the wire going to going to the green indicator light so one terminal will work for both purposes. The other terminal provides load to the rest of the circuit.

 

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                                                                                                      leif

[Bloo]

If you have a wiring diagram you could post, that might clear some things up and enable us to make better guesses which terminal might be which, although I don't really know if it would help. It would be interesting to see.

 

[Jolly_John]

Hi again, Leif. Someday, we'll have a good chuckle about this thread!

 

I STAND CORRECTED. I've researched my flasher number further in an attempt to figure out the answer to the wiring question you initially asked. AND, I've found that my Tung-Sol P229D flasher is NOT the correct unit for the '39 BUICK. But, I bet you knew that all along. This flasher I have is for slightly newer BUICK's.

 

The '39 BUICK takes a Tung-Sol 129SX flasher, which is indeed a two terminal flasher. The specs say it is for flashing ONE 6V-8V 21 C.P. bulb, which we know is correct for the '39 rear-only turn signal set-up. I apologize to all for my incorrect initial info and photos.

 

Now, Leif, back to your original question about how to identify the 6V supply terminal and the load (bulb) side terminal of your present, unmarked two-terminal flasher. Here's a link to a site I found that seems to have the answer. Just scroll down until you get to the two-terminal flasher info section. It appears there are industry standards for the positioning of the terminals on the bottom of flashers. Who would have known!  Best regards, my friend. John

 

http://www.gtsparkplugs.com/flashers-turn-signal.html

 

Edited September 28, 2022 by Jolly_John (see edit history)

[Bloo]

I stand corrected too.

 

I still don't understand how it can have a working indicator on the stalk. Maybe the bulb is hooked between the sides? Maybe extra contacts in the turn signal switch?

 

All the best.

[Jolly_John]

Bloo, I suppose it's possible the little indicator bulb on the shift lever doesn't flash, but rather just lights up until you cancel the turn signal. That's what would happen when the indicator bulb wire is hooked to the 6V supply terminal of the flasher (which I think is what Leif suggested in his last post).

 

If the indicator bulb was wired to the load terminal of the flasher I suppose the bulb would flash in unison with the one rear turn signal bulb being controlled, although the '39 flasher spec indicates it only controls one bulb. However, the miniature bulb in the turn signal indicator wouldn't be drawing much current. John

[buick looks fine for 39]

Hey guys sorry for not replying, I've been off the web site for a while. I really appreciate all your great comments. What I found out is the turning indicator light is indeed hooked between the hot side and load side via the turn signal switch. Current to the light is broken by the signal flasher. I took 6 flashers to friend of mine who is an electrical engineer plus a radio expert extraordinaire and had him a look at them. He took my nos flasher and used that as a control to check the resistance in my used flashers. I ended up with 2, maybe 3 flashers that were serviceable. I used one of the serviceable flashers in my car because I didn't have the guts to risk ruining my nos unit. I found a wiring schematic in the 39 Buick shop Manuel which seemed to show the proper orientation of the hot and load pins and wired my flasher accordingly. Long story short it works!

 

My friend took one of my bad flashers apart by removing an aluminum ring from the unit and that enabled the flasher can to be removed also. Interestingly the metal fastening ring is the same type of band used in vintage radio components. By John's schematics I should be able to tell  correctly which pin is hot and the other load. Unfortunately my disassembled flasher is with my friend 300 miles away. I'll send him the link to the schematic and see what he says.

 

                                                                                               Thanks again

                                                                                                   Leif