Blown Headlights Bulbs #2331
My 1939 Plymouth continues to blow headlight bulbs. The bulbs are #2331. The left headlight is the one that continues to blow bulbs. I have lost 6 bulbs. When I turn on my headlights the bulb commence to become dim until it goes completed out. What should I look for to correct this problem? Your much need help and input would be deeply appreciated.
W. Wms
Off the top of my head, it sounds like corrosion in that circuit, causing high resistance, anywhere from the headlight switch (including the switch itself) to the contacts on the bulb, and anywhere in between; and/or a short in the same circuit, and/or your headlight bucket is poorly grounded.
Pat O'Connor
Assure all your connections are clean and tight, and especially that you have a good ground. 6V systems depend on current flow, any resistance causes that flow to be impeeded causing poor performance. You can check by using a jumper wire to bypass the cars wiring. Check the ground side , then check the power side.
I had previously installed a new wiring harness made by YNZ Yesterdays Parts. The headlight cans had to be grounded and were somewhat difficult to ground. I used solid copper 10 gage wire for the ground wire. The #2331 bulbs snaps in place with a gentle turn. My reflectors were replated by UVIRA Inc. I grounded headlight reflectors to body. Where did I go wrong? Is my ground wire the wrong gage or should I have used stranded ground wiring? All frame and body grounding contact points are clean with tight contact points. The frame and body has double grounding points (Body to engine and Transmission to Chasiss) I still need help with those questions.
W. Wms.
Sounds like you've done your homework and that everything is grounded properly. If it is only the left headlight bulb that is blowing out, I would start at the left headlight bulb, and trace the wiring back to the headlight switch, or the junction where the wiring splits between the left and right headlights, checking for a short circuit.
Pat O'Connor
Grounded reflector??? Not familiar with that. Doesn't the head lamp bulb have three terminals?? Can you post a picture of the bulb? Guess I don't know all the permutations of bulb and reflector lamps, but all I have ever seen do not ground the reflector but rather ground the bulb itself. I wire for low beam one for high, and one for ground. Please describe your system if it differs.
Not sure I can add to the good suggestions already offered on this thread, except that heat can damage things. For example I once had a problem where the fuse on my '33 would fail. And they would fail with the fusible link still intact. Turns out there was corrosion on the clips that held the fuse to the back of the ammeter making a high resistance connection that got very hot and would melt the solder in the cap of the fuse. So it wasn't the current that was burning out the fuse but the heat from a bad connection. Take look around the head light bulb and see if there is anything there, high resistance connection for example, that could be generating heat that would damage the bulb.
A question for you. In your original post you refer to 2331 bulbs but in the title you refer to 2332 bulbs. I don't have a lamp guide at hand for a '39 but notice that there is no 2332 bulb in the standard parts guide that I happen to have and have transcribed into my database at http://www.ply33.com/Parts/group18#18-FA I'd have to look up a 2332 to see how it differs from a 2331 but I am also wondering if you are using the wrong bulbs....
The correct bulb is the PRE FOCUS FLANGE TYPE . BULB #2331. Thanks again for your help.
W. Wms.
Yes, the left headlight bulb blew while the engine was idleing for about five minutes. When I first turned on the headlights, both were bright. But, I noticed that both lights were not the same brightness. Then the left bulb slowly became dimmer and dimmer and then completely went out. I have not had any problems with any of the other lights on the vehicle. I have lost atleast 6 headlight bulbs. Again, I used solid copper wire for the ground wire. Should I have used a stranded ground wire? If so, what gage?
Thanks again for everyones help.
W. Wms.
Quote from: WRSW32A on March 14, 2012, 05:26:44 PM
Yes, the left headlight bulb blew while the engine was idleing for about five minutes. When I first turned on the headlights, both were bright. But, I noticed that both lights were not the same brightness. Then the left bulb slowly became dimmer and dimmer and then completely went out. I have not had any problems with any of the other lights on the vehicle. I have lost atleast 6 headlight bulbs. Again, I used solid copper wire for the ground wire. Should I have used a stranded ground wire? If so, what gage?
Thanks again for everyones help.
W. Wms.
The ground wire should be the same gauge as the power wires. Or it can be heavier gauge. Stranded is better for applications where there is vibration and/or movement, like in cars, as solid copper will work harden and can break more easily.
The fact that the light gets dimmer and dimmer sounds to me like a high resistance connection that is getting hot and oxidizing more thus becoming an even higher resistance connection. If the problem is cured temporarily by replacing the actual light bulb then I'd look for something very close to the light bulb getting hot as where there is heat in an electrical circuit there is current flow across some resistance.
Riffing on FourDoor's post, a bad return path (ground) to the battery can result in high system voltage....
Do you have a volt meter available? With the engine running, what does it read between the generator output and a good chassis ground? What does it read between the battery (maybe the end of the cable at the starter if the battery is under the seat on a '39) and a good chassis ground?
Did you check (see my post last week on this) to see if the bulb is lining up with the terminal right. My bulbs were dieing, much like yours. The new bulbs I had bought were 45 degree off from the terminal. when I move the terminals to meet right the problem is cured. I don't have the slightest idea why that was happening but...... both terminals were making a partial connection on the bulb. Still don't know why they died. The original bulbs that came with the car worked fine, so it had to be the bulb manufactured wrong.
SD Glenn
I think that SD Glenn is onto something. I seem to recall a tail light bulb that was manufactured wrong; the pins on the base did not allow the terminals on the bulb to line up with the terminals on the light socket when the bulb was installed.
Pat O'Connor
Thanks Guys.
I sincerely appreciate all of the input that you have given. I will sort through the information that you have given during the coming week. I will reply and inform you of the outcome. Thanks-a-million, for all of your help and the possible solutions to resolve my issue.
W. Wms.
I am investigating replacing the bulbs with halogen. During the readings, there is a rotational difference between a 2330 and 2331. This would rotate the location of the contact pins on the bulb relative to the socket. Both the 2330 and 2331 are the same candle power, but since they are the pre-focus type, the bulb can only be installed using the three hold down pins. With a different location of the contacts relative to the mounting holes, you could be using the incorrect bulb. The difference is slight so one socket may be ddifferent than the other.
Hope this sheds some 'other' light on the problem.
My PT81 has 2531 bulbs, but these may have been changed by the previous owner so I am not sure these are correct.
Regards
According to the 1936-42 Plymouth Factory Service Manual, the '36 through '39 Plymouths all used a #2331 bulb rated at 32cp for both high and low beam.
Unfortunately there is no entry for the #2331 in my 1970 GE small lamp guide. Similar bulbs in that section all seem to use the C-2V filaments.
Looks like the #2530 is a 50cp/32cp bulb but other wise identical to the #2330. I would guess that the #2531 is a 50cp/32cp equivalent to the #2331.