I’m back with another gremlin. Grab your popcorn. It’s a good one.

The passenger side (US Right) tail lights probably have always been wonky since we bought the car, but probably didn’t realize it until the High Mount Stop Light went out. That’s now fixed. Since then however, we’ve noticed that the turn signals on the right hand side are dimmer than the left hand side turn signal. In addition, I’ve noticed that the right turn signal also faintly activates the left turn signal. When the passenger turn signal is activated it almost acts like the hazard lights are faintly (not fully powered) activated.

So I went into the electrical manual and did some digging around. It looks kind of wild. I’m not the most skilled in electronics, but I know my way around.

Take a look:




On the left side (driver) I’m getting voltage on pins 2, 4 (weird), and 6. All of the lights behave normally on the left (driver) side.

On the right side (US passenger) I’m getting voltage on pins 1 (CA68-1) and 4 (CA68-4). I should be getting voltage on 2 & 6. It’s on this side where I’ve noticed the weirdest behavior. Those red question marks are 0 volts. There should be power on those two pins.

Note, I did change the wire on CA68-4 to CA63-10 because I was seeing high resistance between the contacts. My concern is that wire may have been part of a splice and perhaps that rerouted the power in. Maybe that’s why I’m not seeing power on pins 2 & 6? I find that to be unlikely, as these problems were an issue prior to changing that wire out. I replaced it because I thought it was the problem, but nothing changed.

Anyway, besides the change in that wire. Everything else has been the same and untouched since I bought the car.

I did see that the right and left side marker lights are burnt out, and I’ll be finding replacements for those. Also, the license plate lights work.

The behavior that is the most weird is the behavior when the headlights are activated. When the brake is activated the right tail light goes completely out. The right reverse light also doesn’t illuminate.

Any ideas on the best way to straighten this out?

 

Oh, also the circles on the right with the “S” and the number. Does anyone know exactly what those mean? Are they splices? How do I dig deeper into those?

Thanks!

 

The Electrical Guide (under Symbols and Codes) shows them as Switched System Power Supply ...

 

You did not mention doing so, but checking to make sure the correct bulbs are installed is always a base-line step in troubleshooting issues in the tail lamp assemblies. "Close" is no cigar when it comes to having the correct bulbs installed; bulbs that will fit pin-wise but are not correct spec will cause all sorts of "wonky" behavior...

 

@S-Type Owner - Yes, I have been thinking about this. I suspect that a previous owner messed around trying to figure out the tail lights and it turned into a cluster. They also fitted an after market alarm system to the car. Dumb.

Is there a list of bulbs that have been confirmed to work on the s-type?

The bulbs is one thing, but with both of the connectors disconnected, why would I be getting voltage in the pins where voltage shouldn’t be recorded? That’s the weirdest part.

 

Remember that the car provides power to (each thing) and activates (the thing) by switching to ground.

 

Yes, understood.

Im still trying to understand the power sources. And why those other pins are receiving voltage instead of what’s supposed to be getting voltage on pins 2 and 6.

I feel like a Neanderthal trying to figure that out. I guess I’ll start digging into F53 and work my way towards the tail light.

Anyone else have any ideas on how to best approach this?

I’m also having a tough time sourcing confirmed tail light bulbs. Does anyone have a source for those?

Thanks in advance.

 

@JagV8 Is “switched system” referring to a relay?

 

We’re getting closer. I went digging into F53 and had noticed that there was a decent amount of resistance on the F53. The fuse wasn’t blown, but you could see a hairline crack all the way to the side. It passed continuity but not resistance.

long story short was a false positive on F53. Replaced and we have most of our lights back.

I went back to the right plug to check the voltage on the pins.

I now have voltage on pins 2 and 4. I’m so damn confused as to why 4 is getting voltage and not 6. And how in the hell does the voltage switch from pin 1 to pin 2 after replacing the fuse? Fundamentally something isn’t clicking as to how that happens.

As of now - no reverse light, faint right blinker that activates both sides faintly. Everything else works as it should.

I’m waiting for the rear side marker W5W bulbs. I can’t imagine a W5W bulb messing with the tail light, but as this point I wouldn’t doubt it.

Thats the update for today. 😂

 

I think so mostly but could also be via a module.

For a particular power source just follow it through the Elec Guide pages if you want to find its source.

 

On voltages being where you don't expect (or absent), a wrong bulb could be shorting somewhat and thus powering something it should not be connected to at all.

 

Per your request: