buickbrothers Posted September 29, 2023 Share Posted September 29, 2023 Hi all. Does anyone have a good working head light switch or know a source I can get one for a 1955? I pretty sure my rheostat is dead. It has to be a 55 as a 56 frame is different and the design was changed to eliminate the map light tied to this switch. Note it has 3 terminals across the back and left side with two additional terminals on the right side (black and white wire connected). Any help is appreciated. Link to comment Share on other sites More sharing options...
JohnD1956 Posted September 30, 2023 Share Posted September 30, 2023 It looks like those terminals on the Rheostat are not clean enough to make contact and work. Have you tried to clean the terminals ? Link to comment Share on other sites More sharing options...
EmTee Posted September 30, 2023 Share Posted September 30, 2023 10 hours ago, JohnD1956 said: Have you tried to clean the terminals ? ...as well as the rheostat and the wiper. Put some contact cleaner or WD-40 on a piece of paper between the wiper and the coil and move the wiper over the coil. Check rheostat operation with an Ohm meter. 2 Link to comment Share on other sites More sharing options...
buickbrothers Posted September 30, 2023 Author Share Posted September 30, 2023 Sorry, the picture I sent was the original of the way it looked coming out of the car. Here's what they look like now. However, I may have found the problem and will test later today. The map light terminal (one of the two on the right side that has an arm) was bent and not making contact to the backside of ceramic piece on the rheostat. I have re-positioned where it should be to make contact. Fingers crossed, and prayers to the big guy! 1 Link to comment Share on other sites More sharing options...
buickbrothers Posted September 30, 2023 Author Share Posted September 30, 2023 Update. The map light works now by turning the know to engage the contacts in the rheostat, but the speedometer and gauge lights are still no coming on. I really think I have a ground problem somewhere, but things are not adding up yet. For example, the signal arrows in the speedometer do light up. I know these aren't tied to the head light rheostat, but they ground to the dash. The map light works and it also grounds to the dash and is tied to the rheostat. My dimmer switch is not working so I can't verify the high beam light in the speedometer comes on. One piece of information I have been pondering that may have a bearing. I did paint the gauge housings. Could this be preventing the light sockets from grounding although the sockets snap into the hole and the edges around the socket should be grounding? All I know to try next is Dremel the paint off the gauges where the lights plug in. Frustrating but I think the map light working indicates the rheostat is still good/light switch is still good. Thoughts? Link to comment Share on other sites More sharing options...
JohnD1956 Posted September 30, 2023 Share Posted September 30, 2023 By pass the rheostat with a jumper wire. 3 1 Link to comment Share on other sites More sharing options...
EmTee Posted September 30, 2023 Share Posted September 30, 2023 Do you have a test light or Ohm meter? You should test the rheostat winding for end-to-end continuity. Use an Ohm meter to check across the winding, or apply 12V to one end and touch a grounded test light to the winding and verify the light is lit. If it does not light, probe the winding closer to the grounded end. There could be a break in the rheostat winding. 1 Link to comment Share on other sites More sharing options...
Fr. Buick Posted October 1, 2023 Share Posted October 1, 2023 I have switches if you need a good used one... 1 1 Link to comment Share on other sites More sharing options...
buickbrothers Posted October 1, 2023 Author Share Posted October 1, 2023 So good and bad news. I did jumper power to the dash light terminal as John suggested and all my lights turned on so the ground is good. I was concerned that the paint on the gauge housings was causing the lights not to ground, but this test appears to validate I have good ground. The bad news is that it must be a connection in the rheostat to just the dash light terminal. It's confusing since the map light works and that is totally controlled by turning the rheostat to switch it on and then off. Sorry EmTee, I don't have an ohm meter so couldn't do the test you suggested. Since I now know it's the rheostat and although the book indicates it can't be repaired, I'll take it apart and let you know what I discover. Now, I'll need a replacement switch so Fr Buick, I'll contact you. Thanks all. I'll be doing a couple of other posts - one on wind shield wipers and I'm publishing an approach I used to replace both my defroster motor and seat heater motor with new current motors used today. I did have to make a few modifications on the seat heater motor, but the defroster motor was pretty clean and quick. As usual, thanks for all the help - this was a pain! 2 2 Link to comment Share on other sites More sharing options...
buickbrothers Posted October 2, 2023 Author Share Posted October 2, 2023 Hey Fr. Buick - sent you a PM - please let me know if you have a switch. Thanks. Link to comment Share on other sites More sharing options...
Frank DuVal Posted October 3, 2023 Share Posted October 3, 2023 On 10/1/2023 at 5:53 PM, buickbrothers said: It's confusing since the map light works and that is totally controlled by turning the rheostat to switch it on and then off. But, two different circuits. The map light wire at the switch needs to ground to turn on the map light, and the rheostat varies a resistance in the +12 volts to the dash instrument lights. If you look close, the wiper of the rheostat touching that coil of Nichrome wire does not touch the map light contact. 1 Link to comment Share on other sites More sharing options...
lancemb Posted October 17, 2023 Share Posted October 17, 2023 On 10/1/2023 at 4:53 PM, buickbrothers said: So good and bad news. I did jumper power to the dash light terminal as John suggested and all my lights turned on so the ground is good. I was concerned that the paint on the gauge housings was causing the lights not to ground, but this test appears to validate I have good ground. The bad news is that it must be a connection in the rheostat to just the dash light terminal. It's confusing since the map light works and that is totally controlled by turning the rheostat to switch it on and then off. Sorry EmTee, I don't have an ohm meter so couldn't do the test you suggested. Since I now know it's the rheostat and although the book indicates it can't be repaired, I'll take it apart and let you know what I discover. Now, I'll need a replacement switch so Fr Buick, I'll contact you. Thanks all. I'll be doing a couple of other posts - one on wind shield wipers and I'm publishing an approach I used to replace both my defroster motor and seat heater motor with new current motors used today. I did have to make a few modifications on the seat heater motor, but the defroster motor was pretty clean and quick. As usual, thanks for all the help - this was a pain! Do as @JohnD1956 suggested (he beat me to it). If you're like me and want dash lights on full bright anyway, it's easiest fix. I have done this many times by soldering a wire between the + terminal and the tang on the back of the other side of the rheostat. 2 Link to comment Share on other sites More sharing options...
buickbrothers Posted October 19, 2023 Author Share Posted October 19, 2023 Two updates. 1. I received my new dimmer switch and installed. It didn't solve the problem. I still only have one level - low beam. I'm at a loss as to what the problem can be and how to trouble shoot. I've applied voltage at the terminal blocks to verify the lights are good, and I get both high and low beam. The switch only has three wires. Orange on center terminal and yellow and grey on outside terminals. I've swapped the yellow and grey just in case I had it reversed. The grey should light up the high beam indicator light on the speedometer but hasn't thus far. I have verified I have good ground (all other speedometer lights work and blinker lights). Thoughts/options? 2. I installed a second light switch that I had that came off a 55 Super. It was actually in better shape than the original on the Roadmaster. No difference on dash lights operating even with a much cleaner rheostat vs my original. I'm noting this because of the identical pattern between both switches and the dimmer switch also acting the same way. Am I missing something? I have checked and rechecked wires. I can go with the bypass for the dash lights but wasn't sure there isn't something else wrong that I've missed based on the new dimmer switch and a second light switch having the exact same conditions. Thoughts? Link to comment Share on other sites More sharing options...
EmTee Posted October 20, 2023 Share Posted October 20, 2023 What happens when you disconnect the dimmer switch and connect a jumper wire from the common (+12V) to each terminal (high, low)? Do the lights operate? If so, either the switch is bad internally or there's a problem with the connector fitting securely on the switch terminal. It's hard to determine what's going on with the headlight switch rheostat without testing the resistor coil directly. I'd first probe the wire resistor with an Ohm meter to check for end-to-end continuity and then check continuity between the resistor and the rheostat wiper terminal. If you don't have a meter, you can also carefully probe with a test light. 1 1 Link to comment Share on other sites More sharing options...
buickbrothers Posted October 20, 2023 Author Share Posted October 20, 2023 Apparently, I can just throw the shop manual away and guess my way through this car. I have the new dimmer switch working now. I have not checked yet, but I'll bet my old switch was fine. I wired it per the wiring diagram which is apparently a poor reference. It's pretty clear that the orange wire goes in the middle and the yellow and grey are on the outside terminals. I even swapped the yellow and grey when the switch was only giving me low beam. I also found a dimmer switch photo that still had the wires attached which clearly shows the orange on the middle terminal. Since it was a new dimmer it got me thinking about the wiring again. Since the yellow wire is attached to the light switch terminal it's supplying the power to the dimmer whereas the orange and grey are low and high beam correspondingly. So, I swapped the yellow to the middle terminal since it's the voltage supply and orange to the outside terminal thinking about the dimmer being a toggle between low and high. It works now. I really want to say some a lot of colorful words but I'm more grateful it's solved. For posterity and the next poor guy who's beating his head against the wall, don't go by the books electrical spec if something is working or refer to pic's like below: 1 Link to comment Share on other sites More sharing options...
buickbrothers Posted October 22, 2023 Author Share Posted October 22, 2023 Ok, last update. I have everything working. Reworked the light switch with special attention to the wiper. Thanks, EmTee! I have an Ohm Meter now and everything checked out so it led to the contacts as a primary problem. Switch is still very sensitive to rheostat positional movement, but all lights are working. Big question! Is there an led equivalent to the #57 bulb that will produce brighter dash lights? I like the amber, but these eyes are getting old! 1 Link to comment Share on other sites More sharing options...
EmTee Posted October 22, 2023 Share Posted October 22, 2023 14 hours ago, buickbrothers said: Big question! Is there an led equivalent to the #57 bulb that will produce brighter dash lights? Search the forum, there should be several threads out there on that subject. Some of the LEDs don't work well with the dimmer. Link to comment Share on other sites More sharing options...
Brad Conley Posted October 22, 2023 Share Posted October 22, 2023 Yes, there is. See https://www.amazon.com/led-57-bulb/s?k=led+57+bulb on Amazon. Link to comment Share on other sites More sharing options...
buickbrothers Posted October 23, 2023 Author Share Posted October 23, 2023 Thanks for the link Brad. Yes, I was wondering how they perform with this switch. My back-up plan is to go to a jumper if needed to just run the lights without dimmer. Link to comment Share on other sites More sharing options...
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