This a step by step on how to replace the magnetic brake light switch with a mechanical plunger style brake light switch.
If you don't have the capabity to fabricate a metal bracket or don't know some who can, this is not the project for you!
Let's get the legalese out of the way...
This is what I did and in no way does it mean that it is a requirement for you to do the same. For you to do the same is your choice, your responsibilty. This is for information only...
Read through this info completely for a full understanding before attempting of your own free will.
Many of us have had the EPAS and EPS dash lights illuminate simply because we added a third brake light flasher, trailer wiring harness, or other voltage drawing items to the brake light system.
Don't think anyone ever figured out why, but most suspect a voltage flux in the brake can-bus system causes a detection failure in the magnetic brake switch.
Without detecting the brake pedal has returned to the rest position, brake lights stay on, cruise control is now locked out, vehicle is not decelerating, and nanny starts screaming...
These problems have been fixed by replacing the magnetic brake switch. Let's start this thread with a link to @SlingJockeys original post for the NAPA part #'s he used... Click this!
I went to Autozone and picked up the Duralast mechanical plunger type brake switch part # DR496, female blade connectors, shrink wrap, electrical tape, some 16 guage multistrand wire... okay, I had most of this, but maybe you don't.
You will also need something to fabricate a bracket to hold the switch... I used 1" wide x 3" long flat steel stock. You might choose another material.
Using masking tape pointers in the following photos.
The magnetic brake switch is located in the engine compartment under the ECU and fuse box mounting tray directly aft of the brake master cylinder. The switch and mount is the white pointer and the blue pointer is the connector
Remove two 10mm bolts (blue pointers) from the front edge of the ECU.
Lift the forward edge of the ECU and slide it forward a bit to clear tabs at rear. Gently lay the ECU over toward the engine out of the way.
Remove the wire bundle from the clip (blue pointer) that is attached to the ECU and fuse box mounting tray. Use a small common screwdriver to release the clip and slide the wire connector free of the retainer.
At this point, I should tell you...
Warning! Disconnect the battery!
I did not. I stuffed an old shirt up under the fuse box to prevent it from settling down on something surprising. I also kept all bladed items out of the fuse box.
Remove two each 5mm allen bolts (white pointer). One forward side and one rear side of fuse box. This releases the fuse box and it will settle lower.
Remove three each T-40 torx screws (white pointers) to release ECU/fuse box mounting tray.
(Blue pointer) At the back inner edge of the ECU/fuse box mounting tray is a zippy tied wire bundle. You can clip the zippy tie and replace on reassembly. I was able to flip the tray toward the engine without cutting the zippy.
(Blue pointer) This is the wire bundle connector you released earlier from the front of the mounting tray. Lift up and move back toward windshield to get it out of the way.
(Blue pointer) This is the wire connector for your magnetic brake switch. It releases the same way as the previous clip on the mounting tray. Small blade common screwdriver to release and slide from mount. You can now disconnect the magnetic switch wiring from this connector. Slightly lift locking tab and pull apart.
(Blue pointer) This is the magnetic brake switch and mount. The brake pedal arm can be seen nestled in the u slot.
At this point, I marked the magnetic switch mount for reference if needed for reinstall. Okay, I threw it in the pile of other stock stuff...
(Blue pointer) Remove one 10mm bolt and lift magnetic brake switch out.
Old wired magnetic brake switch and new needing wire harness brake switch.
Newly wired brake switch made from OEM connector, new blade connectors and added wire to keep original length. This switch is normally used in a dry cabin area. Water resistance thinking would be good. I used heat shrink and electrical tape to barrel, connectors, and a short lead down wires.
At this point, you will need to fabricate a bracket. Here, I can't give you specs... the Duralast switch will require a half inch hole...
Tips : Do not bend the bracket to a 90 degree angle as the switch body will not clear the hold down bolt. Walk the angle of the bend in until you get a good alignment. Trial and fitment. You may find it easier to secure your fabricated mount in first then install the new switch.
There is some free play in the brake pedal. When adjusting the switch, check the free play also. The play should act on the plunger only and the brake pedal arm must not contact the body barrel of the switch or breakage can occur.
Of worthy note... I did the adjustment and power on checks at this point prior to reassembly. Accessibility is key here, but keep in mind that your power boxes are not in the original isolation configuration. I used key on only, no start.
New switch installed, adjusted, and operational checked!
For reassembly, reverse order of disassembly. Don't forget any zippy ties that you may have removed. And neatness counts...
I don't know how many beers this will take as I am on a diet and the beer is not...
