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I replaced a passenger side fog lamp bulb and a rear courtesy bulb. I blew the # 17 fuse (15amp) in the driver side eng. fuse box. I replaced it and afterword had no brake lights and was locked in park. I removed the brake switch bracket and saw that it didn't resemble the one in any post in any forums. It didn't have the white plastic part with the two micro switches and cam that could be removed separately from the bracket by removing a bolt and loosening a nut. Mine had the two micro switches and the cam directly attached to the bracket. The switches tested good. I also re-plugged the assembly and held the cam actuated while starting the car and attempting to shift out of Park. The brake lights will not light and the shift is still locked, With ignition off I get the beeping when I try to shift out of Park. I have no error messages or Engine Check message. The car dives and runs fine once I defeat the Park lock out soienoid. I checked all fuses, did a hard reset by disconnecting the Neg battery cable and touching it to the plus battery cable. I reset the switch on the relay in the drivers side fuse box. I have read all related forums and now am at a loss as to my next move. Is this a relay issue? I am a retired electronics tech so you can be technical.
Hi Bob,
welcome to the forum. I see you replaced the fog lamp 15amp fuse.
Check fuse#6 in trunk for stop lamps (5amp).
Now you've got at least 2 different circuits terminating on the light pack that contains your brake lights. Please tell us which of these lights work, which don't:
Brake
Turn
Reverse
Running light (on with headlight)
Rear fog
they all share a common ground. Now I say this for 2 reasons. 1) if none work = bad ground; 2) improperly designed ground layout.
Ground layout you should fix this sometime: Bob take a look at the light pack where you put bulbs in. The ground plane terminates into a rather thin black ground wire. 24 guage or so. One of our forum members pointed this out years ago. Countless X100 members have benefited.
That wire is just not big enough to carry the current needed when most or all of the lights illuminate. On inspection I could see that mine had started to melt.
Easy fix. I drilled a hole in the ground plane, soldered an 18 gauge wire to a ring connector on both ends. Riveted one side to the ground plane, loosened one of the nuts on the wall and grounded the wire to that.
BTW please confirm left right continuity, if a specific light is out on right side, same for left?
Hey, if you went for a ride down the block, test the cruise control. Its tied to the brake switch: does it work? Will tap on brakes turn it off?
Ignition on, step on brake- can you hear the click of the release relay by your shifter?
Bob, I was interrupted a few times while typing this, please excuse redundancies or that kind of thing. Just trying to get the data on the table so we can help.
Just got my (tested good!) brake switch back in and remounted my seat. Tested whether cruise control would kick off when I use brakes. Yes it worked, so brake switch is working. Still no brake lights/locked out of Park. Did hard reset (30 sec) checked ALL fuses. OK. re-seated all relays. Tested all lights...Backup, running, turning, front/rear fog, head lights, courtesy, interior, door, etc. All work, but BRAKE. Pushed reset switch on relay in Driver side fuse box.
I checked rear bulb boards and didn't see any problems. All other rear lights work so there shouldn't be a ground issue. Everything looks normal. Re-charged battery. Windscreen wipers work ok. I will test brake lights at bulb board with a 12v motorcycle battery. I may also remove the lock out solenoid, unless I get a solution soon. BAFFLED!!
So the problem is upstream of the lamp control module. There's not much other than the brake switch, a relay, a pair of fuses and the wiring in between:
Pins 1 & 3 of the relay are at B+ always, and the Black wire out of the brake switch is grounded with the ignition at position ii.
The high-mount is fed from fuse #6.
You can swop the stop relay with one of the other brown relays in the trunk fusebox to eliminate it.
Bob, a quick shot at this. I had trouble and installed the ground wire, but still had brake light not working.
In it's past history someone had installed Standard size bulbs and these are metric. The fit is very different, so might want to have a look at that.
Good luck.
No brake lights (both sides and High brake light)/ Park lock out
All other lights, functions work!!! And no error messages at all!!!
Just replaced my battery. No change.
Ordered brake switch. It's a SLS503. Will replace when it arrives. Can't wait! LOL
The switch in my car has two micro switches and a cam mounted directly to the bracket. This way you need to remove the whole bracket, which I did. The switches tested good, so I re -mounted the bracket and it still will not allow my brake lights to come on, or enable my solenoid for Park lock-out. I tested cruise control and my pushing the brake did kick cruise off as it is supposed to do. I swoped relay #1 for #5 and #3. Checked ALL fuses. Tested brake lights at bulb...OK
My switch dose not have the white plastic part that has the two micro switches and the cam enclosed, which can be removed from the bracket by removing the bolt and loosing the nut. That way you do not need to remove the bracket at all, just the switch.
I did notice, I think the brake pedal should lower once when pressed and again when starting engine.The second lowering does not happen. I wonder if brake boast may be causing problem? I did replace my power steering pump a few weeks ago. It didn't have any problems since then. Only since I replace a burnt fog lamp and blew fuse #17 (15A) in Dr side Eng fuse box.Replaced fuse. Fog lamps ok. HHHEEELLLPPP!!!
Hi CDJ777, Thanks for the help. I have replaced my battery and brake switch with NEW. I had about a day and a half of success, but now I am getting the same problem. I think I am getting a lack of current at the brake switch. I may have a short. I tried swoping the relay at #5. Maybe I'll pull the seat and take readings on the Brake switch tomorrow. Sorry I didn't get back sooner. Just started to find my way around.
Hi Michealh, I see that there is very little to the circuit for the brake lights/Park solenoid, but my problem is that I have no B+ at the o/w center pin of the connector at the brake switch. This is with the IGN. on. I'm surprised more is not causing problems. I have half a notion to run my own B+ to that pin and snip the one that should have B+. Any suggestions? I talked to a Jag service department and the said it would be $$$500.00$$$$ just for diags.
Hi Michealh, I see that there is very little to the circuit for the brake lights/Park solenoid, but my problem is that I have no B+ at the o/w center pin of the connector at the brake switch. This is with the IGN. on.
You should not see B+ on the WO wire. In normal operation it is grounded through the igniton switch at position ii (on). You should however, see B+ on the other side of the switch (US blue/slate) as it ultimately connects to the stop lamp relay.
There lies the problem. I do not have B+ at w/o or what would be 6. I need to by-pass that wire and run B+ from the battery. If I substitute B+ I should get brake lights and a click at the solenoid. This would just be a test, but I need to get some positive results. Any suggestions?
03-20-2020, 06:02 PM
1997 Jag XK8 No brake lights/locked in park
