Shorter version: I am having some issues that I believe come down to my flasher relay and have had a few bad experiences now. I am under the impression that flasher relays are thermal-mechanical and really don't have a lot going on. Given that, I don't understand why some are labeled "positive ground" - what is there for polarity to really affect? I have a negative ground car, does that mean I need to avoid "positive ground" relays? Negative ground relays seem to barely exist online and everything on the old chevy parts sites don't really seem to be labeled at all. Does anyone have a link to a replacement they would recommend for a 6v, negative-ground, 3-prong flasher relay?
The detailed version: I have an original 6v negative-ground 1948 car that had an aftermarket turn signal indicator installed, likely a long time ago. Whoever installed it put a cute little speaker in line with the relay that makes a sound when the relay is open (no lights are on). It worked without issue for about a year although, I noticed the relay had a very sporadic rate. A couple months back while driving during the day it went a bit nuts for a few seconds in terms of rate and then simply went silent. Turned out the fuse had popped and I believed the relay had jammed closed. The lights all still functioned without issue though so I didn't suspect an issue elsewhere in the car. The relay in the car was a Wagner 535 3-pin. If the 3rd/center pin is at the top, it is labeled P, left is X, and right is L - as seems to be 99% of the relays I have seen. It still shows 15 Ohms of resistance from X to L but I read online the resistance isn't always a surefire way to know if it's still functional.
I then tried the Napa 535 which worked but seemed to jam open after around 10-30 seconds of use. Waiting seemed to get it to work again, before stopping again. I tried several times to measure the X to L resistance out of curiosity and my multimeter just goes nuts on this thing. Anywhere from 25 to 125. Looking online, I found some folks talking about how part of this model is now transistor operated and has caused folks grief although, they seem to indicate that problem was for positive ground cars - https://packardinfo.com/xoops/html/modules/newbb/viewtopic.php?topic_id=9320&forum=2
The resistance on the napa part was still bizarre though I got the 3-prong 6-Volt from Chevs of the 40s. That one seemed to work perfectly. I let it run for a while without issue, it made an audible (not as loud as the speaker) click when changing positions and ran nice and steady at a good speed. Been running that for the better part of a month now. Well, while driving home today with the lights on, about halfway home it just stopped and jammed open. So the little speaker just goes and goes, the fuse does not pop, the relay no longer ticks, the lights on the turn signal unit itself no longer come on, and no exterior lights come on (or blink I should say). I know the relay is getting power since the speaker draws power from the same line. It shows 26 ohms resistance which I think is roughly what it was when I got it. I checked that my parking lights and brake lights were still working fine, and they are, so again I don't think it's anything with the lights themselves like a short.
I don't know what to do at the moment besides order another relay. I was looking at either the one The Filling Station has or, trying something like this off ebay. https://www.ebay.com/itm/185952598109 That's when I noticed it being labeled as "positive ground" and formed the question up above in the "shorter version."
I have even more information to add, and I am now even more confused.
I just went out to the car and decided to re-try all three relays as well as no relay just to see what would happen. I did this with all the other lights off.
1. No relay - obviously jams open, speaker stays on, no exterior lights turn on, and the lights on the turn signal unit do not turn on. 2. Chevs of the 40s unit - jams open, speaker stays on, no exterior lights turn on, and the lights on the turn signal unit do not turn on. 3. Napa - Just like before, it worked seemingly okay (a little unsteady) for maybe 30 seconds, then jammed. However, oddly, the speaker stayed on like it was open, the lights on the car stayed off, but the turn signal unit lights turned ON. That makes no sense to me. I was under the belief the speaker being on meant no lights should be on, and I don't know how the turn signal unit lights are on but the exterior lights off. 4. Original wagner - beats so fast it's almost like being jammed closed. It's so fast the lights on the turn signal unit never even manage to fully turn off. But, the lights on the turn signal unit light, and so do the exterior lights. It's impossibly fast for me to tell if the speaker on or off coincides with lights on or off.
I actually did this series of testing twice over as while writing this I thought I must be mistaken in that the Napa unit jammed the indicators lights on, exterior lights off, and speaker on. The pins are labeled in the same manner on all three so I don't understand what is going on here anymore.
The high flash rate you are describing with the Wagner is often associated with a bulb being out or vary low resistance in the system, like an LED bulb.
I use the NAPA one in my 1941. It is slows, close to a second, before the first blink and then gets slowly faster. It never hits a perfectly consistent rate but does get jammed or blink to fast.
If you remove the speaker from the circuit how does it effect the flasher? These are impacted by the resistance in the circuit. Is it possible that something wrong in the speaker unit is drawing more amps?
I have found that having an old car is a constant project that is never done. I think that is a good thing. Keeps me learning new things. Having two from different eras is just a form of higher education.
I triple-checked and all bulbs are working and none of them are LED. That said, I did notice one brake light was dimmer and pulled it. While both filaments appear intact, about half the inside of the glass was blackened. This was my passenger bulb and I know the signal went out on a left-hand turn last night so I don't think this caused it though. I am going to replace both tail lights and likely order a new relay while I am at it. I will try what the filling station has to offer.
I then tested all three relays without either break light in, no difference other than the Napa unit has entirely quit now. It's odd though as with both the napa and second replacement, the speaker jams on but no lights light. I tested the wagner and am confident sound and light coincide. I don't get why with one unit sound and light coincide, but not the other two.
Also confusing - The Wagner seems to spend the most time with the sound and lights going, then only turns off for a very brief moment before it's back on. I would think if the lights/speaker were at issue due to pulling too much power, it would cause them to stay off more than on? I did get to the back of the relay plug but I don't think there is going to be any clean way for me to remove the speaker wire. I have tried pinching the contacts so I can remove both wires and get a better look but so far I haven't had much luck getting it out. I might just have to cut the line to the speaker.
I havent heard of a "speaker" in the indicator system so that could be a source of your problem. The indicator relays down here are required to have an audible "click" which is the relay points doing their thing. Tony
I watched this wonderful video which happens to discuss in depth how these circuits work...
And explains how the relays work. Power tries to go through the relay, the relay has a lot of resistance which causes the lights to NOT turn on, that resistance makes heat in the relay which heats up a bimetallic strip, that strip eventually bends and under the heat and causes the "click" over which then "shorts" the circuit bypassing that resistance and thus allowing the lights to light fully. The metallic strip cools as it's no longer getting heat from the now bypassed resistance, the thing clicks back over, and now the resistance is back in place and begins to generate heat again - thus the cycle repeats. It also taught me that the relays can operate just fine in the open air.
So, I cut open the replacement I got. I have a new one on the way anyways. Sure enough, it's not clicking over. And, unlike my original Wagner, the speaker is activating when the relay should be trying to make resistance - not when it's open. Again, my wagner activates the speaker when the circuit opens and thus the relay is in the cooling stage.
I think under the conditions of this new relay, the speaker there is providing a path for power (least resistance), and thus power is never (or not enough) trying to pass through and heat up my relay. So, I can either ... 1. Remove the speaker entirely 2. Find a relay wired like my Wagner such that it activates the speaker when power IS being sent to the lights, rather than not being sent to the lights, and thus doesn't mess up the heat/resistance stage 3. Rewire my speaker to activate when power is sent to the lights using these new relays, rather than when it's not. Also - it's possible I am backward on my Wagner in terms of when it activates the speaker, it's hard to tell due to being so fast. I noticed it has a much lower resistance so, it may simply be that the low resistance allows it to work in this setup.
I am going to wait for the new relay to arrive so I can try and figure out how it's wired/activates the speaker. If it's activating the speaker in what should be the heating stage, I will either remove or rewire it.
