Turn Signal System 101 - Type 3

[RedSquare]

After having recently spent a significant amount of time diagnosing some odd wiring and functionality problems with the turn signal system in my 1968 VW Type 3 Squareback, I decided to write down what I’ve learned and share it in the hopes that it can be of use to others. While I have some good material here, I’m sure that there are others on this forum that can offer additional info, clarifications and even corrections if I’ve gotten something wrong, and I welcome that input.

So, lets get started. This post will primarily focus on the turn signal system in the 1968 to 1970 Type 3 cars, which also means that we’ll be talking about 12V systems. Much of this content is still valid for non-type 3 cars, as VW used the same basic systems in most of the cars of the period, but there will be some differences in wiring that are specific to different vehicles. That said, I suspect that if you are having a problem with the system in a bug or bus from the same period, this will still be of some use to you.

If you are reading this, it is most likely because you are having some problem with your turn signals and you are trying to sort it out. In order to sort it out, it is important to understand the system you are trying to diagnose. Notice that I said “system” – and it is just that. The turn signal (lets use TS to abbreviate) system in these VWs is comprised of the various wires and bulbs you would expect, and then a combination of two devices to accomplish the desired functionality. One is the TS relay, and the other is the Emergency Flasher (EF) switch. These two devices work together to allow the 4 way flashers, TS right and left, and TS indicator bulbs in the dash to light up in the way that we want. Both the EF switch and the TS relay have a hand in the functionality, and the system will not work correctly if both are not functioning and/or connected correctly. You might think that a problem with the TS system is as simple as just replacing a bulb or the TS relay. And it may be that simple, but if your case was that simple you would have solved it already and wouldn’t be reading this.

Now we’ll talk more about how this system is configured and how that affects the way in which it functions. As I noted at the start, this post is about the TS system in the 1968-1970 Type 3. That means we are talking about the 12V “complex switch – simple relay” system. This system has an EF switch that has 6 pins (7 with the ground pin if present) and a TS relay with 4 pins.

Here is a pic of the EF switch and a diagram of the pins for it.

And while we are looking at these photos and the diagram of the EF switch, you may have noticed that there is not a wire connected to every terminal. There was some standardization of these switches for common use among the various vehicles being made by VW, so there are terminals on this EF switch that might be used on a bus but not on a type 3. Connect the terminals noted on your car's wiring diagram and ignore the others.

Here is a pic of the TS relay, and a wiring diagram of it.

Please note that earlier Type 3 cars had a different system that we’ll refer to as the “simple switch – complex relay”, and these systems can be either 6V or 12V depending on the year. These systems had an EF switch with 2 pins and a TS relay with 9 pins.

Here are pics of the simple EF switch and complex relay:

Simple switch:

Complex relay:

If you have this simple switch/complex relay system, this post will not be of much help to you as the systems have similar functionality but accomplish it in very different ways.

Assuming you have the complex switch/simple relay that is applicable to this post, you’ll also want to spend time getting to know the wiring diagram.
You can find the wiring diagram for your Type 3 here:
https://www.thesamba.com/vw/archives/info/wiringt3.php

So for my 1968 Type 3, the applicable wiring diagram is this one:

You’ll note that the terminals on the EF switch (labeled E3 on this car wiring diagram) and the wiring diagram for the EF switch provided above match. Handy, eh? Same with the terminals for the TS relay (labeled J2 on this car wiring diagram) and the relay diagram provided above.

Interestingly enough, there is actually another wiring diagram for the same range of years (1968-1970) applicable to my car and it reflects the simple switch/complex relay system. These diagrams appear to be for cars that came from the factor with carbs instead of fuel injection. I don’t have the TS system in this diagram, so it doesn’t apply.

By now you have confirmed what type of TS system you have, and presumably you have the complex switch/simple relay system which is why you are still reading. So lets talk about how the system is supposed to function before we start messing around with what may be wrong with your particular system. In my own trials and tribulations, I decided to build a test jig so I could test various relays as I had several with varying degrees of issues. The video below provides a very basic walk through of what a properly functioning system does when you activate the EF switch or the TS relay.


Link


I’m not sure how long videos stay on YouTube, so I’ll also summarize a couple of key points in case the video is not available at some point in the future. Key aspects of this system’s correct functionality include:
1. When the ignition is off:
a. Pulling the EF switch should activate the four exterior bulbs at the corners of the car. This is the only part of the TS system that will function with the ignition off.
b. The TS indicator lights in the dash will not light up with the EF flashers if the ignition is off
c. The turn signal lever has no effect – nothing lights up from the TS lever if the ignition is off


2. When the ignition is on:
a. Pulling the EF switch should activate the four exterior bulbs at the corners of the car AND the TS indicator bulbs in the dash. All 6 lights (2 in the dash, 4 outside) should flash.
b. The turn signal lever will cause 2 exterior bulbs (which ever side you’ve chosen) to flash along with BOTH TS indicator bulbs in the dash. Please note that both TS indicator bulbs flashing when the TS is engaged is not a defect. It is the way the system is designed. Surely you know which way you moved that lever and which direction you intend to turn, right?

If your system does all of the things noted above, and the bulbs are bright with an even flashing pace, then your system would appear to be working correctly. So, assuming something isn’t right with your system, lets talk about some common things that go wrong and prevent the proper functioning of the system.

Common problems that can cause your TS system to not work correctly include:

- Poor ground. This is probably one of the more common (if not the most common) cause of incorrect TS system functionality. You need good, solid, tight ground connections or this system will not work.

- Shorts – some wire has been pinched or the insulation worn through, and it is causing a short

- Incorrect wiring – something has been disconnected or connected to the wrong location, so the circuits are not in place as designed

- Bad EF switch or TS relay – both are possible

- Mismatch of EF switch or TS relay. You cannot mix and match 6V and 12V components, and you cannot mix pieces of the simple/complex vs complex/simple systems discussed earlier.

- Problem with the TS switch in the steering column. These are less common, but not unheard of. Some of these are caused by general wear and time, and some are caused by careless disassembly of the steering column which can damage parts or incorrect reassembly of the same.

- General silliness, random wiring and homemade butchery performed by previous owners. (If present, this will show up as shoddy wiring, laughable grounds, and other stuff that will make you scratch your head.)

Now you are thinking, “OK great. I’ve now read this guy’s PhD thesis on TS systems and still don’t know how to fix mine. There is 30 min of my life I’ll never get back.” Be patient. We’re getting there. There are lots of ways that these systems can fail, and if you don’t know how they are supposed to work in the first place you’ll never figure out what is wrong.

Your system isn’t working right. There are some things that you should check no matter what isn’t working, and other things that you would check that might vary depending on what ain’t right. Lets talk through those.

No matter what isn’t working right, you should first check:

- GROUNDS.
Look at the wiring diagram, and make sure you know what is supposed to be grounded. Then (duh), make sure there is a solid good ground connection. The EF switch may have a ground terminal (term 31) or it may not. If it doesn’t, then the grounding is accomplished by contact between the body of the switch and the body of the car. Sometimes this contact between switch and car is loose, or sometimes it is poor because of the paint or corrosion between the switch and car body. Disconnect the ground strap at the battery so you don’t short anything (remember – the red wire on term 30 on this switch is hot) then remove the switch and clean the surface of the switch and the surface of the dash it is grounding too. Doesn’t look dirty? You already have it apart, so clean it anyway. This is only needed if there isn’t a dedicated ground terminal on the switch, which later versions had. The example below has no dedicated ground terminal, so the switch body to dash is the ground. See how the paint has been removed from the back of the dash around the switch? This is why.

Similar to the EF switch, check the ground for the TS relay. Most of the TS relays have a dedicated ground wire on term 31, but there are some that don’t have a dedicated ground and achieve ground via the mounting connection to the car. Lack of ground, intermittent ground or incomplete ground will absolutely play havoc with these systems and leave you scratching your head. THIS GROUNDING ISSUE IS REALLY IMPORTANT. I see lots of posts where people say they have checked the ground and its good, then spend hours and hours chasing other stuff only to eventually find that their superficial check of grounds led them to gloss over a bad ground that was the real cause of the issue. I cannot emphasize this enough. Really, truly thoroughly verify your ground connections.

- CORRODED TERMINALS
These cars are 50+ years old, and general corrosion happens over time. That corrosion can (and does also occur on the terminals to these switches and relays, and that causes poor connections and additional resistance. Pull the spades off and clean the corrosion off of them and the terminals. For example, look at this photo:

Look at the terminals on the TS relay, and how much rust is on them. Pulling those spades off and cleaning the terminals made a significant different on this relay. And while we’re at it, lets return the “dead horse” I was beating earlier on grounds. See the red-ish wire with the blue plastic crimp on the far-left terminal on the TS relay? Follow it around to the bottom of the pic, where you will see it has no ring terminal (so just bare wire) and is wrapped around a screw and touching a painted surface. That is a really crappy ground, and was part of the problem on this system.

- HAND TRACE EACH WIRE
After 50 years of maintenance, repair, modifications, and goodness knows what, it is pretty common to find…shall we say…”non-factory wiring” in these cars. There aren’t very many wires in the TS system, and if you take the driver’s seat out you can get under the dash and verify where each wire starts and ends. No amount of replacement of switches or relays, and no amount of cleaning/checking grounds will fix your issues if the wires are connected to the wrong places. Look at the wiring diagram and check wire by wire. For example, the wire from the KBL terminal on the TS relay is blue with red stripes, and runs up to the back of the gauge cluster to supply ground to the TS indicator bulbs. Get under the dash, touch the wire with your fingers and follow it all of the way to its destination. Don’t just assume that because you see blue with red stripes on the TS relay, then the same color on the back of the gauge that it is continuous in between. It should be continuous, and it was continuous when the car was first built, but 50 years have gone by and something isn’t working right. Are you sure the problem isn’t between the two ends? Do this with each and every wire in the system between the EF switch, the TS relay and the gauge cluster. Depending your issue, you may need to do the same out to the exterior TS bulbs at the 4 corners of the car, but you’ll have to use a test light or continuity tester for that since these wires are routed in ways that you can’t hand trace in the same way.

- PART NUMBERS
If your system used to work correctly and now doesn’t, you can skip this. But if you’ve just bought the car and the system doesn’t work right, check the part numbers against the parts book to make sure that the EF switch and TS relay are the right ones for your car. People do 6V to 12V conversions and don’t always use all the right parts. A part gives out and someone goes to AutoZone or Amazon and buys what they think is the right part, but isn’t. There were a fair number of changes to these switches/relays over the years and some of them are not right for your car.

OK. So presumably now you have verified your grounds, made sure the terminals are clean, hand traced and verified each wire and confirmed that your switch and relay are the correct ones for your car. Still not working right?

There aren’t too many things left. Let’s explore some of them.

- FUSES ARE BLOWING
You have a short. Find the short and fix it. There is more to explain on how to do that, but this post is long enough already and that is explained elsewhere in the forums.

- ONE OR MORE EXTERIOR BULBS ARE NOT LIGHTING
This is either a bad bulb (hopefully you haven’t read all of this without first checking the bulbs), bad wiring to the bulb, bad ground for the bulb, bad switch or bad relay. Will talk more about how to test the switch and relay later.

- TS BULBS IN THE GAUGE ARE NOT LIGHTING, BUT THE EXTERIOR BULBS ARE LIGHTING AS EXPECTED
Again, check TS the bulbs first. There is an easy way to do this and a hard way. Remember that the TS gauge bulbs don’t work unless the ignition is on. There is a slightly different thing here to be aware of. While the TS system provides power to the exterior bulbs that already have a ground, the opposite is true with the gauge bulbs. They have power whenever the ignition is on, and the TS relay provides the ground. That is why the KBL wire and 49a wires are on different terminals on the TS relay. The KBL wire needs a ground to light up the TS gauge bulbs, whereas the exterior bulbs need power to light up. So you don’t have to pull the gauge cluster to see if the TS bulbs are good or not. All you have to do is put the ignition in the “on” position, then remove the wire from the KBL terminal on the TS relay and touch it to a known good ground. If your TS bulbs light up, then the bulbs are good, and there won’t be any question about it. This is the easy way. The hard way is to disconnect the battery ground strap, disconnect and move the fuse block to the side, stick your hand up through the spaghetti mess of wires behind the dash and pull the gauge back off so that you can remove and check the bulbs. That is the hard way. If the TS bulbs are good but are still not lighting up when they are supposed to, then most likely your TS relay is bad. Will talk about testing the TS relay later.

- BULBS LIGHT UP WHEN TS LEVER IS USED, BUT DON’T FLASH – THEY JUST STAY ON
If you have this condition, then go back and check the wiring diagram again. Something is not connected correctly.

- FUEL GAUGE NEEDLE BOUNCES IN TIME WITH THE LIGHTS WHEN THE EF SWITCH IS ON AND IGNITION IS OFF
This is a weird one, and one that I had on my car. The cause of this when I have seen it is that someone has bought one of the modern TS relays that say they will work with these cars – and they will – kind of. You can buy these on reputable VW sites, and they have all of the correct terminal numbers printed on them. Here is an example of one that was EMPI branded and bought on Amazon:

See how the package has the stock VW part number 211-953-215C? That would lead you to believe that it has the exact same functionality as a stock one, but it doesn’t. The K1 terminal on this relay is the KBL terminal on the wiring diagram which is for the TS gauge bulbs. You’ll remember that this car (and any car that requires TS relay 211-953-215C) is looking for a ground to light up the TS gauge bulbs. Unfortunately, K1 on this relay provides 12V power not ground. So it is providing power to a circuit that already has power but no ground, and the TS bulbs don’t work.

Here is a video of one of these modern replacement TS relays hooked up in my test jig.


Link


OK, so what does this have to do with the fue/l gauge bouncing? Well, people will tell you that you can make the TS gauge bulbs work with this relay by jumpering the wire from the gauge bulbs to the 49a terminal instead of K1 (KBL) and low and behold your TS bulbs will work. And actually, that does work. I’m not sure I fully understand why, but it finds a back-fed ground through that terminal. However, if connected in this way you can also make the fuel needle bounce. With the ignition off and the EF activated, you are back feeding 12V back into the gauge cluster through the TS bulb sockets and it finds ground through the fuel gauge’s ground connection, slamming the needle against the stop for a full tank then back to empty every time the lights flash. Solution – don’t jumper it in this way, and use the correct relay.

So you’ve been all through this stuff and suspect that you have a bad TS relay. Let’s talk about the relay, how to test it and how it works in the first place. It is pretty simple, and it only provides the function of creating the intermittent opening and closing of contacts that causes lights to go on and off when asked to do so by the EF switch and/or TS lever.

There are only 4 wires going into the relay. One is power that comes from the EF switch, one is ground, one is 12V power (cycling on/off/on/off) back to the EF switch that goes to the exterior bulbs, and the last one is ground (also cycling on/off/on/off) to the TS bulbs. So without too much trouble you can check these.

a. First, is it “clicking”? These are “electro-mechanical” relays, so the current causes an electro magnet to cycle on/off that opens and closes contacts inside the relay. Those contacts opening and closing make the audible click you hear each time the lights go on and off. If you don’t hear the click, then the contacts aren’t closing and the relay won’t work.

b. Is the power wire from the EF switch providing 12V to the TS relay? Put a multi-meter on the terminal and test it.

c. When the relay is active, is the terminal from 49a providing 12V on/off/on/off? Put a test light on that terminal and ground the other. The test light bulb should blink like a TS. If it doesn’t, then the exterior bulbs are not getting the current they need.

d. When the relay is active, is the terminal from KBL providing ground on/off/on/off? Again, you can use a test light, but you have to find a hot wire to connect to since the relay is providing the ground.

If your TS relay is clicking, you are getting 12V power cycling on/off from 49a and you are getting ground cycling on/off from KBL, then your TS relay is fine.
Here is a video of one of these TS relays that I disassembled and put on my test jig so that you can see how it works.


Link


It is possible to clean the contacts within these relays and get them functioning again, and I did just that with the TS relay in this video. The main relay opened and closed just fine but the load-sense relay that operates the TS gauge bulbs wouldn’t cycle. I cleaned the contacts on it gently with contact cleaner and fine sandpaper, and now it works again. If you decide to open your TS relay up, be very careful with it. It is 50+years old and lots of these bits are very brittle. I have broken one opening it because I didn't understand its internals. Ask me and I'll share what I know with you.

And finally, we come to the EF switch. I don’t have any clever thoughts to offer on how to test these, other than to say that if you’ve tested and confirmed that everything else works, then your EF switch can be bad. I think the EF switches failing is a pretty unusual occurrence, and the TS relays giving up is by far the more common problem.

I hope this saga has been of some use to you. As I noted in the opening comments, I’m happy to accept any constructive criticisms on parts of this that I may be mistaken on, or things that could be stated more simply. It is my sincere hope that this helps someone diagnose and correct TS issues with a minimum of stress and frustration. Be patient, be deliberate, double check your work, and I’m confident that you will get your system working again.

[Bobnotch]

One thing I'd like to point out is that VW changed the flasher (EF or TS) relays in 71 to use the more commonly available round canister style found in domestic cars. They even added a bridge of sorts to hold the relays in place, and they changed the wiring as well. So what you describing above is more for the 67-70 crowd, depending on which switch /relay combo you have. Just a heads up, and another monkey wrench in the works.
_________________
Bob 65 Notch S with Sunroof
71 Notch ...aka Krunchy; build pics here;
http://www.thesamba.com/vw/forum/viewtopic.php?t=249390 -been busy working
64 T-34 Ghia...aka Wolfie, under construction... http://www.thesamba.com/vw/forum/viewtopic.php?t=412120

[RedSquare]

Thanks Bobnotch. This is just the kind of feedback I was looking for. I’ve edited the 2nd paragraph to reflect this correction. I also noted that 1967 was the change over year from 6V to 12V, so there are some 1967’s in either voltage. Do I have that right?

[sjbartnik]

[RedSquare]

Got it. I’ll go back and edit that to see that this is reflected correctly. Thanks.

[highwheelerboy22]

After readying through this and looking at the diagram I’m still trying to find my relay and no luck. I know it’s there because I have left turn signals but I get a buzzer and no lights for the right turn signal. Where is the relay in a 71?

[Bobnotch]

[Trekker182]

[RedSquare]

Trekker - I hadn’t seen your question until just now. Sorry for the delayed reply. Rapid flashing of the TS is related to resistance. The system is tuned (more or less) for the resistance associated with the stock wiring and bulbs. If you have LED bulbs, they have very low resistance and the TS relay isn’t tuned for that. Or if you have an incorrect relay for your year of car, that may contribute to it as well.

[Bobnotch]

[Trekker182]

[RedSquare]

Makes sense. Glad you got it sorted.

[sjbartnik]

[Trekker182]

[GDOG57]

You can use 2 relays for the ‘68-‘69 style. I used 2 Napa EP-26 relays. One for turn signals,the other for hazards.

I was getting the fuel gauge bounce with just one relay.
_________________
'57 oval window deluxe,Agave green(L240) 2276cc w/51.5 IDA's
'57 type 2 panel ( L31 dove blue) project daily driver,Singleport 1955cc
'69 Squareback (L30A Royal Red)

[Wilson]

This is amazing, thank you!

BUT...did I miss the work around for making the gauge blinkers work with the new newer turn signal sending unit?

Thx,
W

[RedSquare]

Yes you did, but only because there isn’t really one that I found. My post is inadvertently misleading in hinting at that. Because the new style flashers provide intermittent power instead of the intermittent ground expected by the car, they don’t work correctly. Now I did see that the post just prior to yours has a suggested work around using the new style relays, and that person says it works. I haven’t tried it so I can’t verify that, and I’m not sure how an alternative wiring would solve this issue of power instead of ground.

The only reliable solution to this I have found is to:

1. Replace the relay with a known good one. This is hard since any 50+ year old relay sourced from the internet will be suspect. If you find a NOS one, you’ll pay through the nose for it - if you can even find it.

2. Open and clean your current relay. I didn’t have great luck with this. They are very hard to open with out damaging them, and the contacts corroded again not long after I cleaned them.

3. After I made this post, I actually stumbled across the fact that the old Pantera sports cars used the exact same relay, and there is somebody making new relays and advertising them for Pantera’s. They weren’t expensive, so I bought one and it worked perfectly! The come just as a board (no housing) so you either need to gut your non-functioning one and put this inside or make another housing. I’ll post a link to that product.

If you have a go at the previous poster’s work around on the EMPI or Napa style with power, let us know how that went.

[RedSquare]

Here is the Pantera relay I noted above.

Turns out that the 1970's sports cars called Panteras have a pretty good following today, and they used the exact same TS relay that the VWs did. This matters, because you can buy a new relay from a company that supports Pantera owners that has the same terminal wiring for your VW as the OEM relay did (including the cycling ground) - see link below.

https://www.pantera-electronics.com/signal%20flasher.htm

I bought one of their relays and tested it in my Type 3 and it worked perfectly. Its $50, so its not a huge investment. The challenge is that they just send you the guts of the thing with no housing, so you need to create your own housing for it. You can take one of your old junk ones that doesn't work, CAREFULLY open up the case, pull out the antique insides and put this new relay inside, then close it back up.

Double check the Bosch/Hella part number before you buy and make sure that their relay is compatible, but mine was. Note that they make both an LED and standard version, so be carefgul what you order.

[Zwitterkafer]

RedSquare, thanks for posting that! How reassuring that a proper unit with KBL cycling ground is actually still available new! And an adjustable flash rate to boot!
_________________
"Criticism comes easier than Craftsmanship"
- Zeuxius, 400 BC

[Wilson]

Oh cool, thx!!