I am cutting and pasting from a prior post as I don't know how to add and re-post yet:




Hello Members:

Getting a Check Brake Light signal on the dash of my 2001 XJR. Both Rear Brake Lights went out at the same time however the Brake Light on the Rear Deck still works. I'm not certain if the switch on the Brake Pedal controls all 3 lights and I don't want to change the switch if it is not necessary. Any help would be appreciated.


O.k. I changed the security module and the left side Brake light still does not come on. Of course I changed the bulb too. I temporarily wired the left side to the right side so they both light when the brake pedal is depressed. The "check rear lights" message still comes on every time the pedal is depressed and being OCD it drive me crazy. Is it possible the switch on the brake pedal is bad? I would guess that it is a simple on/off switch but could be wrong. Any ideas?


Update: Now the Tail Lights do not work either??? Checked fuses etc. but all o.k. I noticed that the Brake Switch on the Brake Pedal sticks from time to time and I need to tap it to release. Can all these issues be tied to the Brake Pedal switch? Very frustrating. Thanks for your input.



googletag.cmd.push(function() { googletag.display('div-gpt-ad-13'); });

 

I've moved your question from General Tech Help to X308 forum. Members here with the same model will be able to help.




To REPLY to a thread, type in the Quick reply message box below the post and then press the Post Quick Reply button.

To post a new thread, click on the black Post New Thread button at the top left of the existing threads in any forum.

Graham

 

Capital, if your high mount (3rd brake light) works, then I can tell you that your brake switch is working fine. If none of the brake lights are working, then this can be either 1) the brake switch, 2) brake light relay (relay #5), or fuse #8 (10 amp fuse). Any of these failing can cause a complete loss of brake lights.

I would say to get yourself a multimeter and do the following checks:

1) On the top of fuse #8, you will see 2 very small metal points in the top of the fuse. Using the multimeter, touch one of those points with the red lead and the body of the car with the black lead as you are looking at DC voltage. When the brakes are applied, do you see 12 VDC? If yes, see #3. If no, continue.

2) Assuming you don't have 12 VDC at the output of the brake light relay, move the red lead over to the orange/green wire on the brake switch. Apply the brakes again. Did you get 12 VDC now? If yes, then your brake light relay is most likely bad. If no, move the red lead over to the white/blue wire on the brake switch. Do you have 12 VDC there? If yes, then your brake switch is bad. If no, then you have a wiring problem between this point and the ignition switch and will require hand over handing the wire to isolate the problem.

3) Assuming you have 12 VDC at the output of the brake light relay, attempt to put the car into reverse to see if your back-up lights work. If the back up lights work, then the problem is isolated to the back-up light wiring. If not, then it is a common problem. See #4 and #5

4) If the back-up lights work, use the multimeter to measure 12 VDC at the orange/green wire going into the lighting control module as the brakes are applied. If you don't have 12 VDC now, you have a wiring problem between the brake relay and the lighting module. Hand over hand the wiring to isolate the problem. If you do have 12 VDC, move the red multimeter lead over to the blue wire (and the orange/yellow wire, one at a time). Make sure you have 12 VDC at this point. If you don't have 12 VDC, then you have a lighting control module issue. If you do have 12 VDC, then repeat the blue wire (and orange/yellow wire) checks at the rear of the car. If you have 12 VDC now, you have bad bulb bases or a wiring problem internal to the tail light. If you don't, then you have a wiring problem between the lighting module and the rear of the car. Hand over hand the wiring.

5) Assuming that you don't have reverse lights either, first confirm you have reverse light power going to the lighting module by measuring for 12 VDC on the black/red wire when the vehicle is in reverse. If you don't have 12 VDC, then we have multiple issues. Write me and I will help narrow things down. If you do have 12 VDC, then put the car back in park and do a resistance check from the black wire on the lighting module to the chassis. You should be getting a very low reading (under 5 ohms is good). If you are getting a high reading (ie, greater than 5 ohms), your problem lies with the ground wire. Repair the ground wire. If you are getting a low resistance reading, then your lighting control module (even though it is a new one) is bad.

Hope this helps. If you are confused or need more help, let me know.

 

Wow, that's a really detailed explanation. I can tell you that the backup lights work, so do the fog lamps and the signals/flashers. Don't have a complete loss of Brake lights as the right side works (hot wired it to the left side temporarily so they both light). I guess the Relay is working if the right side lights?


The 2nd module is used so I guess it's possible that it too is bad however I put the original module back and get the same results, still no Tail lights and same Brake light problem.


I really appreciate you taking the time to help me out with this problem.

 

Capital, if you have just a single light out, you can follow what I wrote, you will just need to focus on the one side. From the sounds of things, you may have a bad wire and/or a bad bulb base. Odds are, the problem lies between where you tapped in the wiring from the other side and the electronics module. That may help narrow down where you need to look. Problems like this can be hard to figure out unless you know exactly what to look for. if you know you have power at one end of the wire and not at the other, probably best just to admit defeat and run a new 18 gauge wire from the computer to the tail light.

 

I haven't as yet figured out the Brake Light issue but will continue to try. Not sure what pin coming out of the SCLM corresponds to each Brake Light.


Still very much in the dark as to why the Tail Lights no longer light. Can't seem to find a fuse dedicated to them. I have been using the rear For Lams as Tail Lights temporarily.


Any additional direction would be appreciated.

 

Linking BOTH lights to a single semiconductor 'MIGHT' overload it and cause the IC HIGH SIDE PWR SWITCH to fail.

The system was designed to operate ONE brake lamp per semiconductor.

Just an observation??

Better to power the inop lamp with the HMSL relay. It can handle the additional power.

bob gauff

 

Hi all,

not sure if this is related or not but the other day i had a brake light fail and stop lamp fail on my 2006 s type, i replaced the bulbs but same issue, someone mentioned swapping out the recm so i got a second hand one from a breakers with the same model number and still the same problem, i also then swapped out the bulb holder with a different one, no change, i checked the fuses in the boot and all seemed to be good, what have i missed? when lights are turned on and i press the brake pedal apart from the warning error on the dash the 2 passenger side lights mentioned dim when pedal is pressed as opposed to getting brighter??

 

This is the X308 (97’-03’ XJ8/R) section. You want the X200 section.

However, check all the bulbs on both sides of the rear bulb (trays) holders. If one looks even a little bit dark, replace it. Check the license plate lights while you’re at it.

 

Double click on image to expand , right click to drag around to your area of interest

The 3rd brake light working means you have a good brake switch and its ground path through the ignition switch at pin 2 , pin 1 is not proven yet

Pin 1 is a ground path for the Body Processor Module as well as pin 2 again

For you to be getting the bulb check light means the bulbs have ben correctly commanded but the current sensor is seeing a lacking current from a open bulb or lacking bulb ground path ( common on this model from reading others ) or a bad connection to and from the bulbs outside of a ground

incorrect bulbs can also do this

" counterfeit " bulbs can also cause problems being out of Spec even though they will light

So by you having a check bulb light you do not have an agreement between the commanded light ( this proves pin 1 is good ) and the expected current through the bulbs

So you would be looking for something to the right of the BPM on the picture as the BPM is apparently alive

By wiring the left brake lights into the right the current sensor is still looking at the "missing " left circuit and sees a fault

In changing the SLCM it probably needed to be software matched with the master label software # under the hood near the rear firewall

 

Capitalman1.

At the beginning of this thread you mentioned "... I changed the security module..". Did you find and match the VICAT numbers? Even if the primary numbers on the module cover match, VICAT suffixes not matching can get you odd lamp behavior.