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S4/S5 Turn Signal Switch and Plug/Connector Wiring Mayhem
I’ve been through wiring diagrams, factory service manuals, forums, and more and I’m here firstly to share the information I’ve found on this topic in one place to hopefully give a head start to anyone walking the same path and secondly so that maybe some other people can fill in the gaps so it can be completed and the confusion can be cleared up because I’m going insane.
THE PROBLEM I own a Series 5 Rx-7, coupe, NA, manual, no airbags (that last one seems to be important to the wiring diagram). The turns signal switch I have (not original to this specific car) does not activate the blinkers, high beams, or light up with panel illumination (I don't have the turn cancel switch). However, through the research I will lay out next, I was able to determine what wires going into the plug do and hook up toggle switches that allow me to activate my blinkers and high beams. This means the problem is located somewhere in the switch and plug area.
WHAT I KNOW SO FAR There are a lot of confusing issues surrounding the research I've done for this. I'm going to list out the things I've found and make special note of the inconsistencies that seem to appear in the FSM, wiring diagrams, and reality. Starting off with the basics:
Functions (Actions) of the Switch
Turn Signals. When the switch is operated down or up it activates the left and right blinkers respectively.
Turn Cancel. The switch is designed to work in tandem with a Turn Cancel sensor which is located on the steering column and cancels the turn signal (returns switch to ‘off’ state) when the steering wheel is turned beyond a certain point and back.
High Beams. When the switch is pulled towards the driver the high beams are activated. If the lights are off this will only activate them as long as the switch is pulled. If the lights are on,I think it toggles the high beams on and off.
Illumination. The switch illuminates with panel illumination. This happens when the vehicle lights are set to anything but ‘off’.
S4 and S5 Turn Signal Switches Are NOT Identical They look identical though based on my research. However, the difference is in the layout of the pins and so the plug for the switch is also identical but the wires will be in different locations. This is important to what I’ll get into later. To tell them apart I believe you can check the MPN (Manufacturer Part Number) that is molded into the casing on the back where the plug attaches.
S4 MPN: 513133 S5 MPN: 513318
I believe these are correct, but it’s only based on listings and pictures I’ve seen for the switches and what series people say they are from.
Plug Wire Functions by Color A lot of this conversation surrounds the plug itself that connects to the switch. There is inconsistency in where resources say the different wires should go, but at least the function of each wire remains consistent. B (black) - Ground. B/R (black w/ red stripe) - Turn Signal Power Supply. Gives power through the “TURN” fuse when ignition is ‘on’. G/R (green w/ red stripe) - Left Turn Signal. Power from B/R is routed here to activate the left turn signal. G/Y (green w/ yellow stripe) - Right Turn Signal. Power from B/R is routed here to activate the right turn signal. G/W (green w/ white stripe) - Turn Cancel. I think power comes into this wire from the cancel switch to activate cancel. R/G (red w/ green stripe) - Illumination Power Supply. Power supply for the light bulb. Gets power when panel illumination activates. R/W (red w/ white stripe) - High Beam Power Supply w/o Lights. Routed to ground to turn on high beams when lights are off. R/Y (red w/ yellow stripe) - High Beam Power Supply w/ Lights. Routed to ground to turn on high beams when lights are on.
Pin Layout for Plug This is where everything hits the fan for me. This is about which wire goes to which pin in the plug, and thus which pin on the switch. Because the s4 and s5 switches are different the pin layout for the plug is also different.
Note that all these layouts are as if you’re looking at the plug from the side that it attaches to the switch. An asterisk (*) denotes empty (no wire).
Based on the Wiring Diagram (WD) for a Series 5 the plug should have the following layout: Since my car is a series 5 I expected mine would be wired the same way but it’s absolutely not. Below is how my car was wired. Notice that only TWO of the pins actually match but that is not the only big difference, I don’t even have the same number of wires. My plug has two empty pins but the WD only shows one. I think this must be related to the R/G wire. The WD shows two R/G wires where I only have one. So I don’t have the duplicate and I don’t know what purpose the duplicate serves. Regardless, it is simply not present on my car with no signs that there once was a wire but it has been removed.
I hit the forums hard at this point. I saw that a lot of people also had two empty pins and their layouts, while different from mine, also didn’t match the wiring diagram. My head was already spinning. It feels like for some reason we all have different wiring layouts for this one plug and none of them matched what they should be and, due to a missing wire, couldn’t be rewired to match.
But I tried anyway. According to the WD, the R/G wire simply provides power for the illumination light bulb. So I decided to put it in one of the two possible locations and worst case the light won’t turn on. I can live with that. So I wired it like the diagram said it should be and plugged my switch into it. It partially worked. My high beam control worked like I expected it to but the blinkers did not. Based on my understanding, for the high beams to work the B, R/W, and R/Y wires had to be in the right place.
This was progress.
However, it wasn’t good enough and I started to consider what I should have done earlier in this process, that the switch was partially broken. Maybe the high beam mechanism worked but not the turn mechanism. Looking into how to test that was when I found out the s4 and s5 turn signal switches have different pin layouts but look the same so I needed to know which mine was. Based on my MPN findings (above) I determined what I actually had was a s4 switch. So I decided I would actually need the plug to be wired like an s4 plug to make it work so I opened up the s4 WD. It shows the pin layout as this:
It took me some time to notice it so I’ll point it out right away right now. This is the mirror of the s5, they are simply opposite layouts. When I wired it this way, nothing worked. So I went into diagnostic checking the switch.
I’m not completely certain I know for sure how to tell a s4 switch and an s5 switch apart so I did the continuity checks for both. I couldn’t get any continuity doing the checks which confused me further because I at least know that the switches high beam controls work but the continuity test didn’t back that up.
Furthermore I realized the FSM is disagreeing with the related WD for this connector. In the s5 WD it shows the blank pin on the ‘bottom’ row but in the FSM it shows it in the top.
Also it appears to show two grounding pins (E). At this point I’ve completely lost my mind with the lack of straight and consistent information on what should be where and I’m hoping that someone here knows why I’m so freaking confused and what is even going on.
WHAT I NEED I need to know, for sure, if my switch is fine. The continuity test says it’s busted, but the fact that in a certain configuration it does turn on high beams says otherwise. I need to know if my switch is a s4 or a s5 and how to tell them apart for sure. I need to know the correct plug wiring for a s4 or a s5 depending on what switch I have or end up with.
Last edited by The_Pied_Shadow; 02-13-22 at 04:22 PM.
Reason: Added correct S5 MPN
>> WHAT I NEED >> I need to know, for sure, if my switch is fine. The continuity test says it’s busted, but the fact that in a certain configuration it does turn on high beams says otherwise. >> I need to know if my switch is a s4 or a s5 and how to tell them apart for sure. >> I need to know the correct plug wiring for a s4 or a s5 depending on what switch I have or end up with.
Switch on the left is for an S4. Pictures are fuzzy but if you look closely you can make out MPN 513133 for S4 switch. Switch on the right is for a S5, both w/o air bags. Looking from the back both switches are upside down. The connectors are reversed and the pinouts are different. The S4 uses a different dash wiring harness.
That means I have a s4 switch as I suspected and that's at least one piece of this puzzle. Thank you for that. If someone could share pictures or just write down the layout of the wire colors in the connector especially for an s4 I'd appreciate it. Just to check against the WD and other things I've found.
Thank you so much for this. So a piece of the puzzle that I didn't know I was missing is that I'm an idiot and have been reading the pin layout diagrams backwards. It makes sense that they are from the side of the plug that the wires enter from I don't know why I thought it was the other side.
That doesn't change a whole lot except my original layout is backwards but it's still wrong.
Can anyone with a s5 confirm if their plug has 2 R/G wires on it? I see that the s4 does, and the s5 diagram says it should but I don't have this additional wire....and the plug was wired in a way I haven't seen any diagram suggest is correct....but there also is any other car that someone could have swapped this particular little harness from right?
With my S4, I opened the switch up and several of the solder joints were cracked. I realized that they were cracked when I had the turn signal activated, and wiggled the connector on the back, and it would sometimes work.
Once I reflowed all four switches on the dash cluster (Headlights, Turn Signals, Cruse Control, Windshield Wipers) as well as the computers on the left side of the car footwell, all of those issues went away. Those joints are really old and vibration likley has broken those electrical solder pads
With my S4, I opened the switch up and several of the solder joints were cracked. I realized that they were cracked when I had the turn signal activated, and wiggled the connector on the back, and it would sometimes work.
Once I reflowed all four switches on the dash cluster (Headlights, Turn Signals, Cruse Control, Windshield Wipers) as well as the computers on the left side of the car footwell, all of those issues went away. Those joints are really old and vibration likley has broken those electrical solder pads
So I actually opened mine up yesterday and did find the problem, however, it wasn't as fixable as the solder joints needing to be flowed. Unfortunately there was a burn out on the circuit where the R/B power for the turn signals come in, thus why the signals don't work but the high beams do. I decided I had nothing to lose by trying to see if I could jury rig a repair for the circuit with a piece of copper and some solder and it did work initially at least proving to me that this was indeed the issue. But it didn't hold.
At the very least I know the core issue and I just need a new switch so I'm ordering one specifically for an s5 and wiring the plug for s5....but I still have a mystery on my hands and I'm hoping it doesn't become relevant again once I get the s5 switch. My car was not wired liked the s5 wiring diagram suggested it should be. So I'm not sure whether to revert it back to what it was or to what the WD said it should be as I've never had a working switch on this car during my ownership so I can't say "well it worked before so just leave it like it was".
Does anyone have a picture of this plug for an s5 that I could compare to? Thanks.
If it did not hold, is making me think that there is something else going across that, that is burning it out. Has the fuses been changed to something incorrect so it is getting "all of it" instead of popping when there might be a short?
It almost sounds like it is masking a short somewhere and the highbeam circuit burning out was just the result
Hey thanks but I've been through these threads and they really mostly further confirm that there is some kind of confusion with the s5 plug. From what I can tell, there are maybe two versions of the s5 layout, the one put forth by Icemark and the one the official Wiring Diagram says and they are significantly different. However, now that I realize I've been looking at the diagrams backwards, I know my car was wired like Icemark suggests it should be. And at least a few people claim to verify that it's correct. So I'll be wiring it like that when I get my s5 switch. But why the official diagram is different than the reality of these cars still boggles my mind. If it checks out when I put the s5 switch on I'll reply again with a full synopsis of what I discovered and hopefully others in a similar position won't need to search through various threads and read dense conversations to pull a few bits of information and piece them together for their specific issue.
If it did not hold, is making me think that there is something else going across that, that is burning it out. Has the fuses been changed to something incorrect so it is getting "all of it" instead of popping when there might be a short?
It almost sounds like it is masking a short somewhere and the highbeam circuit burning out was just the result
I hadn't considered this. Let me clear up one thing tho, the high beam circuit is fine, it's the turn signal circuit that fried out. And you underestimate how sketchy my patch job was. I'm talking the actual coper lines in the circuit is what had a burnout not at one of the pins where there is normally solder. So I tried to get a small piece of copper wire to bridge the gap and hold it in place with some solder. It was sketchy at best and I assume what happened was it simply fell off in there. I may take it apart again to confirm. But the TURN fuse is a 15a like is should be. I'm guessing it probably burnt out back when I thought it was a s5 switch (or more accurately, when I didn't know there was a difference) and I plugged it in to the s5 pin layout. What do you think?
02-13-22, 12:23 PM
S4/S5 Turn Signal Switch and Plug/Connector Wiring Mayhem
