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-   -   Dash brake light stuck on shuts off when I push in clutch (https://www.yotatech.com/forums/f116/dash-brake-light-stuck-shuts-off-when-i-push-clutch-307160/)

polaratomic 03-05-2019 06:09 PM

Dash brake light stuck on shuts off when I push in clutch
 
Hello yotatech! I've been a lurker here since I got my 95 4runner last year, but I registered an account after I couldn't find this issue through searches of old posts.
As the title states the brake light on my dash is stuck on all the time and the only way to get it to shut off is to press down the clutch. I know it is correctly working with the emergency brake because if I hold down the clutch to get the light to go off then engage/disengage the parking brake the light will come off and on normally. If I engage/disengage the emergency brake with the light already stuck on I can also see it get brigher or dim when I engage/disengage the emergency brake.
I've also verified my brake fluid level is at max in the master cylinder, but just to go overkill I went ahead and bled the brakes and changed the front pads and rotors since it was needed.
The dash brake light still is on and only goes off when I engage the clutch. The other issue that started at the same time is my cruise control no longer works the cruise light comes on, but will not set and engage. I wonder though if the cruise won't engage if it also detects the dash brake light has been tripped?
I have also tested all fuses in the compartment on the driver's side by the pedals, and tested or visually inspected the fuses in the engine bay. I didn't pull and test the large fuses that screw in from underneath just looked in to make sure the link wasn't broken or corroded.
I appreciate any help to point me in the right direction to troubleshoot the issue.

keycw 03-06-2019 04:47 AM

might try changing the switch for the ebrake. looks like 84380?

http://parts.lakelandtoyota.com/show...rimLevel=18419

Paul22RE 03-06-2019 05:36 AM

The two switches may share the same ground and the clutch switch is completing the ground since e-brake switch/ground wire is bad?

snippits 03-06-2019 06:16 AM

I have to finesse my e-brake handle some times to make sure the e-brake rod engages the e-brake switch. If not, the brake light will stay on.

Make sure the e-brake switch is actually in the off position by looking up under the dash at the e-brake rod and switch engagement area.

jbtvt 03-06-2019 07:28 AM

Sounds like a short somewhere. I happen to have the wiring open right now for my swap and see that both circuits share a ground by left kick. If I had to guess, maybe you have corrosion creating a short at a switch or connector and when voltage from the clutch switch passes through the same ground, the increased voltage drop causes the brake switch light to function normally. You should have junction block 1C between your fluid level indicator, could be something there, or the fluid switch itself, or brake switch itself. Yes, your cruise ECU will not allow cruise to work if brake light is on. Test all your switches on this circuit and wiring coming to and from them. Download an FSM if you don't have one, they should still be around on the wayback machine.

Edit: actually it looks like the clutch switch is only powered through start, not run. Does pushing the clutch start cancel switch affect anything? Could be mechanical fault after all, but easy enough to test the switches and circuits either way, gotta go to work so can't really think about it now.

Paul22RE 03-06-2019 07:54 AM

Clutch switch, e-brake switch & low brake fluid switch are all connected to cruise control computer (at least on an '87). I would try unplugging each switch separately starting with the low fluid one and see what happens.

polaratomic 03-06-2019 08:17 AM

I'll start unplugging switches one at a time this afternoon and see if clutch switch, ebrake switch, or fluid switch unplugged gets the light to go off. I'll report back with what I find.

Paul22RE 03-06-2019 09:34 AM

When you got each plug off, also short the 2 contacts in the plug and see what happens. If there is only 1 contact in the plug, try grounding that contact and see what happens.

polaratomic 03-13-2019 07:18 PM

I have an update on this, it's definitely tied to the clutch switch. With the clutch switch disconnected the brake light is on permanently, shorted the connection to the clutch switch and the light went off and stayed off but would still come on with the emergency brake as normal. When I reconnected the clutch switch the brake light again came on and would only go off if the emergency brake was down and I pressed down the clutch switch. So at this point I'm thinking the clutch switch is bad.

Co_94_PU 03-14-2019 06:56 AM


Originally Posted by polaratomic (Post 52420331)
I have an update on this, it's definitely tied to the clutch switch. With the clutch switch disconnected the brake light is on permanently, shorted the connection to the clutch switch and the light went off and stayed off but would still come on with the emergency brake as normal. When I reconnected the clutch switch the brake light again came on and would only go off if the emergency brake was down and I pressed down the clutch switch. So at this point I'm thinking the clutch switch is bad.

Disconnect the cruise control box and see if the behavior changes, if so there is likely a short in the cruise and if not there is likely a wire shorted between the brake and clutch wires.

jbtvt 03-14-2019 11:57 AM

^True.

What clutch switch you checking anyway, the one above or below the pedal? Just check continuity for both clutch and both brake switches, and compare to diagrams. What you describe would still suggest a brake switch to me, behaving in the manner I described last post. I just don't see where you'd be getting current flow from in either clutch switch with the key at IG and cruise control off.

polaratomic 03-16-2019 06:11 PM

https://cimg9.ibsrv.net/gimg/www.yot...4929aab85d.jpg
Clutch switch.
This is the switch I can short and get brake light functionality like normal.

Although I think you all are definitely on the right track don't think this switch is bad but closing the parking brake circuit to let the brake operate normally. I found the Cruise control and troubleshooting section from the FSM and following the flowchart I ended up at "Open circuit in wire harness between terminal 14(3) of ECU and terminal 1 of parking brake switch or brake warning light.". I also found an electrical diagram from the FSM for the cruise control components so just need to do more poking around.


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