2000 Discovery 2

The Facts

• Brand New Brake Switch Installed
• No brake lights when depressing the pedal
• Center Diff Light (x) turns on when brake pedal depressed

I need to check fuses. Anything else I should be looking for?

 

The CDL light appearing when you step on the brake pedal is certainly interesting.

Can you walk us through what happened prior? Ie - why did you replace brake light switch? That might help diagnose.

Side note -- if there's an issue with your taillight bulbs shorting, the circuit boards in the rear taillights, or wiring issue with the high mount center stop lamp in the cargo door, it can cause weird issues. That said I would not expect the CDL light to show up. (I had a shorted out bulb in the center brake light, I was getting weird symptoms with HDC, cruise not working, etc)

 

@nashvegas basically no issues prior. Then had the shift lock stop working. Noticed the brake lights were no longer working, so I swapped the brake light switch on the pedal. Since the issues the ABS light and TC light is on all the time and the CDL light comes on when the brake is pushed...so weird.

 

OK. This stuff will drive you crazy but generally there's a simple reason here and generally it's related to water causing corrosion somewhere, on something...

1) Any water leaks on the truck up front (windshield, cowl, front sunroof, front A-pillar, front-roof rails?). Check both edges of the car under the carpet up front driver and pass side... is it wet ? Note this area can be soaking without the top of the carpet actually feeling wet, you need to carefully unscrew/remove the sill trim and get under it to verify. Could be that your interior fusebox (below steering wheel on the left side of the dash under the panel that swings down) is getting wet, corroding, when this happens it causes all sorts of nonsensical issues. If you look at that fusebox and see any rust stains down the front, or water on it, you have a problem most likely. It's a pain in the rear to get it out, but on mine, I had to remove it, open it up carefully (you can probably find my post about it), and then it was covered in green corrosion everywhere).

2) Similarly -- there are several ECU's in the lower right kick panel behind the plastic panel that can also get wet. Maybe could cause same thing. But I'm betting fusebox.

3) I would go ahead and pull both taillights out. Pull the back of the lamp assemblies off where the bulbs mount -- is there corrosion? If so get replacement lamp assemblies or replace the back circuit boards with good used ones. Either way, go ahead and replace all of your brake light bulbs including center lamp. Left, right, center. Get the right bulb, not a substitute.

4) With the old brake light switch swapped back in, does this CDL light still come on? I'd try that to see.

5) Did you replace the brake light switch with the original style or the new style? In my case I replaced an original with the new style and it came with a little pigtail harness. This is the old style -- https://www.roverparts.com/brakes/switches/XKB100170/. This is the new style --> https://www.roverparts.com/electrica...RoC1esQAvD_BwE

(I used new style to replace old style on my 2000, apparently it's more reliable but you have to have the adapter harness)

6) Pull the brake light switch out of its mount and see if it changes anything.(keep it plugged in and manually depress/press it)... I don't think it would change anything but it's possible a bad brake light switch could back-feed or something if adjusted improperly.

One note: I bought a brand new brake light switch a few mos ago. It was *BAD* out of the box. So I don't really trust these things... I spent a day trying to troubleshoot why my brake lights still weren't coming on. Turns out it was a bad (new style) brake light switch.


Hopefully that helps?

 

All solid points Nash! I can attest to a few old style bad out of the box switches or died within a month. They are cheap and I keep a spare in each of my D2s, I think I bought them off amazon a year or two ago..