I know pre 2004+ is #90 but I can't for the life of me find which one is the brake light fuse on my 2006.

All lights work, regular driving, both blinkers, rear fog, side lights, front blinker side repeaters, but all 3 (upper as well) brake lights are out today. Applying brake allows shifting, so not pedal switch.

 

Checked the brake light (pedal) switch, it has continuity with plunger out, no continuity with plunger pushed in (which is as it should be).

 

 

 

 

Sssssoooo.....long saga once again. I'm installing an LED flexible light strip that follows the trunk contours. It shows blue-white as running lights, strobe left & right turn signals yellow, strobe middle to left & right emergency blinkers yellow, bright white on back up and SUPPOSED to show red when applying brakes.

For some unknown reason the brake lights were out yesterday. Did everything I could think of to find a fuse (none), checked wiring, brake pedal switch = nothing.

Gave up and called it a day after 9 hours of frustration. Went out today and the damn brake lights were working. Smfh!

Anyway, the lead for the brake lights will not work because our Jags have both rear lights on while night driving and second element brightens on brake application. So it confuses the electronic switch that is supposed to monitor brake lights applied to LED switch from running lights to braking. Been trying to figure out where the wiring is for the third brake light to attach the brake lead there for the strip.

On a side note, when I bought my kitty, in getting the safety inspection one of the license plate lights was burned out. I replaced it and all was good. A bit later I posted that the chime signal for leaving lights on had stopped working (it worked for a couple of months) and never got an answer to how/why/where to look and fix it. While working on these lights, I noticed BOTH license lights were out. Having installed LED bulbs I figured no way they both had gone bad. Looked for the fuse. It was blown and damned if the lights left on chime now works.

I just LOVE electrical crap!!!

 

Dell, for the brake light, that would be fuse F51 in the passenger bay fuse box. But, since you are able to shift the car out of Park, this would tell me that this fuse is good and the brake switch is good.

Ok, so, this is leaving only a few things that can be the issue. If you look at the brake switch, you should see a green wire with a white stripe coming off of it. That should lead to a plug not to far from the switch. The wire will continue straight through the plug (known as JB-2 plug) and then continue on to a second plug not to far away (known as CA170, which is in the footwell area, most likely behind the plastic there on the left side. It is possible that the wire between JB-2 and CA170 is bad. This is where you can disconnect CA170 and at pin 15 (side going to the rear of the car) do a resistance check to chassis ground. If you are getting say 10 ohms or less, then the wiring between CA170 and the tail lights is good. If you are getting anything above 100 ohms is confirming your problem is towards the rear of the car. This will tell you if the problem is under the dash or towards the rear of the car.

If you want to go into more specifics on the problem, i would tell you to get your hands on what is called a "cable chaser". You tend to find these used for CAT5 cables and determining which breakers in a power panel is the source for a circuit. But, in your case, what you would do is disconnect the plug from the brake switch and connect the source portion of the cable chaser to the green/white wire (pin 1) and then using the wand, you will start following the wire towards the back of the car. You will hear the wand making a tone, telling you that you still have good wire between the source unit and the wand. Where the tone ends, you are really close to where the wire break is. From there, you can access the cable bundle and determine the source of the problem.

 

As always thanks Thermo. Check my PM on another problem (3rd light) & attempt to light the brake portion on the LED strip.

 

Dell, all 3 brake lights get their power from the same point in the trunk. so, if you are not getting power to your brake lights, then the 3rd brake light is not going to light either. You fix one, you will fix both of your issues.

 

Thx, Thermo the brake lights are now working, idk why they weren't or why they are now, lol. To recap the challenge, when hooking the LED strip to the rear light wire inputs, they work like this.
1. blue-white running lights are hooked into and powered by the normal rear light (lower one) wire. This way they are only powered on by light switch at night, not on and wasted during the day.
2. Yellow color signal to left strobes left and right strobes right hooked to L/R turn wires and emergency flashers signal a strobe from center to left and right.
3.The bright white back up light change is wired to the back up light wire.

Here is where my challenge arises. If I hook the wire to turn the strip red when brakes applied to the rear brake light it fails because our Jags light both lower and upper on light switch and then light the "2nd" filament in the bulbs for brakes. Therefore when I attempt hooking the LED strip to that wire, the strip controller thinks the brakes are being applied. Even taking the lens backing plate off and tracing the "power/ground" circuitry to the top brake light, it appears a power side goes to lower bulb and upper bulb (only on right side). Then it appears that on the upper bulb it has a separate "power" inlay on the left side of the upper bulb (this made sense to me). So thought, well Yeah maybe I'll have to tap in to that power run. But.....touching the brake LED wire to that left side still activates the brake light on the strip without pedal being depressed. Smh!

This precipitated my desire to find access to the power feed to the upper 3rd brake light to power the strip. Just couldn't see or find an obvious feed. The last thought was as I PM'd you, although a royal p.i t.a., would be to run a completely separate wire from the brake pedal switch all the way back to the trunk to switch the brake light LED module when brakes applied.

 

Dell, let me look at some drawings and let me see what I can figure out. It may be possible that your LED light strip is what is the problem, not the power you are feeding it. Could you send me the model of your light strip so I can double check how it needs to be wired up. Some cars apply 12 VDC to cause the lights to light and others ground the ground wire to cause the lights to light. It may be possible that you bought a model that requires the ground to light things.

 

So the attached pics have a battery from my Random Orbital Polisher (12V) that I pretested the strip with. It functioned exactly as described on the "wiring" paper provided. I really do think the brake light so called malfunction is just because our Jags have power to the bulb through the 1 wire lead. If I test the left contact on the circuit board for the brake light (upper) with one of those grounded screwdriver probes that light the handle with power, it does not light up on the left circuit board run. That is why I figured the secondary brake light filament lights when brake depressed. BUT, with a multimeter there is 2-3 V showing on this "dead" circuit. Not enough to illuminate the probe but enough to trigger the strip module when I touch the wire to that circuit run on the rear of the lens cover.

 

 

Now, now......

 

 

chinesium
Any metal whose properties fail to meet the expectations for the role in which it is found, and whose source is probably "Made In China". "
My wrench broke in three places... It must be made of Chinesium.

Chinesium
A crappy metal made in China that's used in Apple products to ensure that they break just outside of the warranty or when you try to repair them.

I will defer to the reader's assessment as to the P.C. content and use of the word.

 

yes
im the roseanne of jaguar forums

 

Dell, looking into this, part of the problem may be that both the running lights and the stop lights use an orange wire. So, could you be getting this mixed up? The stop lights are connected to pin 5 (should be at the end of a row of pins) where the running lights are powered from Pin 3 (should be in the center of a row). After that, you may want to trace the harness back on one side and at some point in the trunk, you should see an orange wire with a green strip break off and start running up to the 3rd brake light. That is where you would want to tap into the wiring for the 3rd brake light.

As for why it is doing what it is doing, I cannot come up with a good reason. The nearest thing I can say is that the little control box has an internal fault. This is where I would wire it up and test one function at a time. Verify that they all work that way. Then turn on the running lights and do another run. You can then work up to having the running lights, reverse, and turn signals all on at the same time and see what it does at that point.

The one thing that I am not sure about is you have the 7 wires coming in, but you have 3 wires going to the light strip. This would tell me that you either have a data line to another controller (potentially hidden inside the light strip itself) or it is using the lines to handle both power and ground and depending on which is grounded and which has power determines what lights light. If you have multiple functions happening at the same time, the same wire may be trying to both ground and power something. This would cause things to act goofey since the same wire can't do the dual functions that are in contradiction with each other.

 

Thx again, Thermo. I know what you're saying, I thought the same thing. Connected to wrong feed. That's why I pulled the backing plate off and traced the imprinted circuits. Found or rather traced the upper brake light that connects to the left side of the bulb with no power to illuminate a screwdriver like test probe, but lights the strip and shows a very low voltage below the threshold of the screwdriver type probe. I think my best bet will be trying to find the 3rd brake light feed or running the wire from the pedal. Thanks for looking though. As soon as my new upper radiator pipe assembly shows (mine just broke = another thread), I'll re-tackle this.

Btw, I have 2 of these strips from different suppliers and they both do the same thing, lol.
Although the instructions on the 2nd one are even more obscure in translation than my above post if that's possible.

 

I had brake lights on all the time this week so took out the brake light switch (easy-peasy, twist it off under the dash at the brake pedal then remove one 2-pin connector). On the bench with the ohmmeter on the 2 terminals the switch would measure near zero ohms with the plunger out and infinite with the plunger pushed in as expected BUT...if I wiggled the plunger around when it was out the resistance would jump up to 5k to 20k Ohms. When the plunger was in and wiggled around it could jump up to a few hundred ohms. Clearly not working correctly. The switch body has 6 little plastic catches to hold it together. I pried on a couple of those at a time with little flat head screwdrivers until I got it to open up and I could get at the spring loaded electrical contacts. I spent 10 minutes cleaning those contacts with emery cloth and then sprayed in some electrical contact cleaner. After that the switch and the brake lights worked perfectly.

My point is when you measure with the volt/amp/ohm meter you need to take into account that the car isn't stationery on a bench at room temperature. Your brake light switch might be bad in the car but not on your bench.