I know, I know, I hate these, "Why does my car do this?" posts, but I'm stumped. Our '52 DeSoto wagon has an original, but '53 DeSoto column and wheel, with a non-self cancelling switch. The wiring harness is one from Speedway with a fuse panel and integral flasher, the new harness (GM wiring style) is splice into the DeSoto columns original harness. The left rear brake light never comes on UNTIL either flasher, right or left, is activated. Then it comes on as it should, until the next time the brakes are applied without using a turn signal. (You can the see the problem here) Of course we don't always turn when stopping, leaving us with one brake light out. I'm thinking the problem must be in the original switch behind the wheel, something corroded or worn? The non self-cancelling part is a PIA, I'm always driving around with one or the other on like an old man. (Which I am, but that's another issue.) Any thoughts before I get a new column? I like the ivory original wheel, and hate to lose it, although we don't need a 17" diameter steering wheel... Edit: It (left rear brake light) actually seems to randomly not come on until the turn signals are activated. I just backed the trailer into the barn, brake lights worked every time.
Usually corroded contacts get clean with use. But burned away contacts don't heal themselves. And loose parts don't heal themselves. I forsee a few hours spent taking it all apart and fiddling with it until you find the problem, then a while longer to figure out how to fix it, or that it can't be fixed. Aren't old cars fun?
I think # 1479859......kinda pricey, but worth having a spare IF you keep the column. I see them on eBay, maybe you can take it apart and make a more common switch work or get another used column and make the steering shaft fit (to keep the wheel). But it does sound like switch problem.
I'm on the right track thinking it's the switch itself, it seems. It's a ******* getting the horn ring and wheel off, but, it's gotta be done. The column is beautiful, and I love the ivory wheel, but randomly non functioning brake lights warrant an immediate fix. If I have to put a new column (and switch) in it, that's one way to move the column up at the dash, because the HUGE wheel is too close to the seat.
I have used this method several times making compleat harness, You can use your Original turn signal lever as the toggle switch, Just a thought
I'm thinking that if the turn signals work right otherwise you have the brake light switch wire from the car hooked to the wrong wire in the switch harness.This being the 53 Desoto wiring diagram out of the wiring diagram manual. The other is the color code for GM turn signal switches.
Thanks, the wiring harness is a new one from Speedway, I had the diagram for a '53 from Rhode Island wire (there was a new harness from them uninstalled in the car), and spliced the wires from the original switch to the new harness per the schematic. The key here is that they work intermittently, and when the left rear doesn't work, turning on either signal makes it work. Until the next time it doesn't...
From looking at at this add for a 53 switch there isn't going to be any chance of putting a GM style switch inside the housing Turn Signal Switch# 1479859 - DeSoto - Chrysler 6 & 8 - 1953-54 - NOS - Blue Star Performance
That I know, I'd replace the column with a tilt wheel feature, then either adapt the original wheel or get a new, appropriate looking wheel. I hate to lose that beautiful original ivory wheel, but...
It's 6 wires. The tough part was identifying the color coding of the original columns wires since the colors (linen wrapped) had faded.
A few minutes with meter or powered test light would ID the function of each wire. Start with one wire and see which other ones it has continuity; continue on thru the other wires listing the results, then you should be able go over the list and figure out each wires function.
Can you clarify what you mean by "it works when switch is in left or right turn"? Sure, the left rear bulb should be on solid when switch is in "no turn signals" or in right turn position. In the left turn position it should be blinking and the right rear bulb should be solid. The way you word it sounds as if the left rear "brake light" will be on when the turn switch is in either left or right. If so, the left rear contacts in the switch are broken inside or misaligned. OR, you could have a bad ground at the left rear turn bulb. How to test, simply turn on the tail lights, have the turn signal in NO TURN position, and brake pedal depressed. If the left tail light does not come on you have a bad ground at the left rear bulb.
I think he means that he has to wiggle the switch to get it to make contact on the brake light circuit.... I have had similar problems with 50s Chevy switches, when they designed them, they didn't really expect people to want them to still work 70 years later.
To clarify, when the light doesn't work, engaging either Left or Right, turn signal, the left brake light will then come on AS IT SHOULD. Until the next random time it doesn't. The Left turn signal ALWAYS works, the Right ALWAYS works, it's brake light Left side only that randomly doesn't work. It isn't that light will work with the switch in either position, it's that when using the turn signals the left side brake light always works. When it doesn't, briefly engaging the signals makes it work. We just drove the car now, the light worked (we checked) before leaving, and again when I pulled it in the garage, brake lights both work. It's the random times it doesn't that I am concerned about.
Bad ground on the brake light. Check if you are actually getting power at the light. I had this problem with a 64 impala and had to run a new ground for each light wired back to the main body because with age rust and greased hinges the lights on the trunk lid only worked when they wanted to
So, I went out an hour ago, because bad ground can cause all sorts of perplexing problems, and you're one of many (and I thought of that myself but dismissed it because the tail-light side always works) to suggest it, and added a separate ground wire to that housing. Before I did so I checked the brake lights, both came on as they should (which they do most of the time). Afterwards, I checked again, and they both came on, so at least I didn't screw anything up by adding a ground. Just went and checked again, they both came on again. Yay. Whether or not they'll work tomorrow morning I don't know, but before that side wouldn't come on at least 50% of the time. I know because I followed my wife home yesterday towing the trailer and at least half the time that left brake light wouldn't come on. I had checked with a Multi-Meter before and found no current at that left brake wire, at the switch, nor at the light, but I may well have not had the meter itself grounded. Thanks for making me rethink the obvious, I hope that's all it was.
Grounds can play havoc just like positive , make sure all bulbs have Good grounds , some times add if necessary, I have added Solder to br*** to tighten up bulb connection, OP if you decide to change steering column you can with thought cut & weld the splines shaft of your Ivory steering wheel to new column .
Although it may not be the Turn Signal Switch(and granted I understand not wanting to dis***emble to get to it) I'd probably dis***emble the switch. It's old (like me) and probably needs a good cleaning. I'm using an original switch on the Studebaker and I had to dis***emble it, clean the contacts and once that was done it has worked fine since then. On the roadster (just got the VIN today I used the column out of a 59 Pontiac and the Turn Signal Switch is really different (mounts on column tube and is activated by a "hairpin" on a rod). I luckily had two of them, took them both apart..they were both nasty like the Stude. After cleaning and building my own "plug" it works fine. Good luck, you have some very nice automobiles
I'll say that it's very unlikely to be a ground problem. The tail, brake and turn filaments all use the same common ground, with two out of three working the problem is almost surely inside the switch. You almost certainly have a burned/corroded contact in the switch which may or may not be repairable. The way these are configured is there are four separate contact points for each turn/brake light. You have one contact point that connects to the actual light. This one is switched between the other three depending on switch position. These three points are brake primary, brake secondary, and turn. With the turn switch in the 'OFF' position, the rear light is connected to the PRIMARY brake light contact point on each side. This is the contact point giving you your trouble. When you switch to 'turn' (either side), the light contact is moved to the TURN contact (the side selected) and the off-side light is connected to the SECONDARY brake light contact. Now generally, the primary and secondary brake contacts points are on one longer contact but if the primary end is damaged this will give you exactly the symptoms you're having. I would expect to see some damage on the light contact also, but the less-used secondary and turn contacts are still good enough to make a good connection. As you have a basic six-wire switch, if it proves impossible to repair/replace you can byp*** the bad contact in the switch with a relay and some rewiring. You could install just one relay on the bad side, but as you're towing a trailer I'd recommend doing both rear brake/turn lights to remove the extra load off the switch. Plus any 'issues' that may crop up with the trailer wiring won't impact the switch. Use the turn power to the front lights to trigger the relays. Diagrams here: Technical - Turn Signal Wiring How-To Part 2 | The H.A.M.B. (jalopyjournal.com) Because you have functioning front turns, you won't need the 'front' relays, just the rear ones. I'm not a fan of modern tilt columns as they just can't be made to look 'right' without extensive mods. Plus you usually lose your 'vintage' steering wheel. Here's a cheaper alternative....
19Eddy30 had a good idea with the trailer harness module idea. Since you have a good switching going on in the front lights, add a trailer harness to fix the rear.
Try CRC 2-26 Multi-Purpose Lubricant, they sell small cans at home depot for a little over $4. I have gotten lucky with using this stuff on switches I had problems with.
I thought that same thing, "How could it be a ground when the taillight ALWAYS works?" I checked continuity from the housing to a known good ground, using my multi-meter. Good. Before I took the column apart, I put a ground wire from the housing to the body. (Bocam's Razor, "The simplest thing is always the answer") Viola. The brake light now works every time, all the time. I think that when I checked for continuity to ground (this was when the light wasn't working), simply pushing on the housing with the probe for the meter made the housing ground. Likewise, when I checked for current at the wiring to the light, I may have not had good contact with either the ground or the wire (I was using a connector in the harness) to the meter. At any rate, the lights, checked randomly over the past two days, works every time now. I'm relieved not to have to dig into the column switch.
I'm glad that has fixed it, although I still suspect that the switch is a heavy contributor to the problem. You stated that the tail and turn lights worked every time, with the brake working every time when the turn switch was operated. As the turn/brake are the same filament, the only variation is how the brake light is fed at the switch, i.e. which contact was feeding it. Electricity can be funny stuff though... I suspect what was happening is the tail/turn circuit path was good enough to overcome the poor ground at the socket, but the added resistance at the switch on the primary brake contact was just enough to drop below the voltage threshold needed to get current flow. Improve the ground, now you're above that threshold and the light works. If the problem returns and fiddling with the ground doesn't cure it, you'll have to dig into the switch again...
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