Brake light switch puzzle., Why is this happening, what am i missing? Options

[drem914]

I had my brake lights go out on me at WCR. A couple of members offered to help replace or the switch and now I am thinking I should have taken them up on the offer.
The problem is when I install the new switch it does not work. The switch is good mind you. I have tested it outside of the car and it switch current off and on. Wwhen I plug in the electrical connection with out mounting on pedal bracket, the switch works. It closes the circuit defaulting to ON when left free. Now when I go to mount the same switch to the bracket, the switch no longer works. It is not about how much the arm moves. as soon as the switch base touches the bracket the switch motion is meaningless. it just won't close the circuit for bright brake lights. What is causing the short? Is there supposed to be a separator between the switch and the bracket? Any suggestions at this point?
TIA

[lierofox]

There is no separator/insulator since the switch should be isolated by virtue of the fact that the screw threads on the switch are just inserts pressed into the plastic and shouldn't be connected to any other metal in the switch. (I've used both the URO and the Wittrin brand switches, and both of them are built roughly the same, and are both adjustable.)

In terms of adjustment, is the washer on the pedal able to FULLY pull away from the switch while it's being depressed, as in there's a gap between the switch arm, and the washer? If the washer is still touching the switch arm at all, the brake lights won't come on. The brake switch only makes contact and closes the circuit when it reaches the absolute end of stroke, which is set using the locknut/screw on the switch, I have mine adjusted so that the washer pulls away from the switch arm and actuates the lights just the tiniest bit before I start to feel any resistance from the brake pedal.

With the switch mounted but no wires connected, are you able to get continuity between the terminals when you push the pedal?

(And, if you're concerned about a short, with the wires disconnected and the switch mounted, are you able to get continuity between either terminal and the vehicle chassis ground?)

If you have the wires connected (should be one with a bundle of ...I think 3 wires that provides power into the switch as well as teeing off to your reverse lights and another circuit, and another single wire that actually goes to your brake lights) do you see 12v on one side and ground on the other with the brake pedal at rest, and then do you see 12v on BOTH sides with the pedal pushed down?

[drem914]

There is no separator/insulator since the switch should be isolated by virtue of the fact that the screw threads on the switch are just inserts pressed into the plastic and shouldn't be connected to any other metal in the switch. (I've used both the URO and the Wittrin brand switches, and both of them are built roughly the same, and are both adjustable.)

In terms of adjustment, is the washer on the pedal able to FULLY pull away from the switch while it's being depressed, as in there's a gap between the switch arm, and the washer? If the washer is still touching the switch arm at all, the brake lights won't come on. The brake switch only makes contact and closes the circuit when it reaches the absolute end of stroke, which is set using the locknut/screw on the switch, I have mine adjusted so that the washer pulls away from the switch arm and actuates the lights just the tiniest bit before I start to feel any resistance from the brake pedal.

With the switch mounted but no wires connected, are you able to get continuity between the terminals when you push the pedal?

(And, if you're concerned about a short, with the wires disconnected and the switch mounted, are you able to get continuity between either terminal and the vehicle chassis ground?)

If you have the wires connected (should be one with a bundle of ...I think 3 wires that provides power into the switch as well as teeing off to your reverse lights and another circuit, and another single wire that actually goes to your brake lights) do you see 12v on one side and ground on the other with the brake pedal at rest, and then do you see 12v on BOTH sides with the pedal pushed down?

Thanks for the info and reply. I am now going to have track down more issues as result. Yesterday while driving Generator light stayed on while driving. then wound up losing all gauge electrical, tach response, no brake light on the combo gauge with the e-brake pulled up. No it is time to go back and start checking fuses and relays to see if was just a part heading down hill and the first sign was the brake lights not working. Also was not get good throttle response on the drive back while the red Gen light was on but getting dimmer??? Ahh, the joys of old car ownership.

[lierofox]

There is no separator/insulator since the switch should be isolated by virtue of the fact that the screw threads on the switch are just inserts pressed into the plastic and shouldn't be connected to any other metal in the switch. (I've used both the URO and the Wittrin brand switches, and both of them are built roughly the same, and are both adjustable.)

In terms of adjustment, is the washer on the pedal able to FULLY pull away from the switch while it's being depressed, as in there's a gap between the switch arm, and the washer? If the washer is still touching the switch arm at all, the brake lights won't come on. The brake switch only makes contact and closes the circuit when it reaches the absolute end of stroke, which is set using the locknut/screw on the switch, I have mine adjusted so that the washer pulls away from the switch arm and actuates the lights just the tiniest bit before I start to feel any resistance from the brake pedal.

With the switch mounted but no wires connected, are you able to get continuity between the terminals when you push the pedal?

(And, if you're concerned about a short, with the wires disconnected and the switch mounted, are you able to get continuity between either terminal and the vehicle chassis ground?)

If you have the wires connected (should be one with a bundle of ...I think 3 wires that provides power into the switch as well as teeing off to your reverse lights and another circuit, and another single wire that actually goes to your brake lights) do you see 12v on one side and ground on the other with the brake pedal at rest, and then do you see 12v on BOTH sides with the pedal pushed down?

Thanks for the info and reply. I am now going to have track down more issues as result. Yesterday while driving Generator light stayed on while driving. then wound up losing all gauge electrical, tach response, no brake light on the combo gauge with the e-brake pulled up. No it is time to go back and start checking fuses and relays to see if was just a part heading down hill and the first sign was the brake lights not working. Also was not get good throttle response on the drive back while the red Gen light was on but getting dimmer??? Ahh, the joys of old car ownership.

Well let's see... The generator light is fed power through fuse 9 to the light and then to the regulator on the board in the engine bay, fuse 9 also feeds the gauge indicator lights, several gauges themselves (including the tachometer), the brake lights, AND the brake warning lamp on the gas gauge (through the emergency flasher unit's, which is powered through the emergency flasher switch) Edit: "through the flasher relay, which is powered from the emergency flasher switch"

If fuse 9 is blown, making bad contact in the holder, or the wires plugging into it on the back of the fuse panel are corroded and not making great contact, that would affect the gauges, brake lights, and the brake indicator, and make the generator light behave wonky.

And that's just the protected side of fuse 9!

As far as throttle response, the supply side of fuse 9 branches off and goes back to the relay board and feeds 3 things: Coil power for the "Power Supply" relay, coil power for the Heater Fan relay, and terminal #15 on the ignition coil.

Eesh...Fuse 9 is really important.

[drem914]

Well let's see... The generator light is fed power through fuse 9 to the light and then to the regulator on the board in the engine bay, fuse 9 also feeds the gauge indicator lights, several gauges themselves (including the tachometer), the brake lights, AND the brake warning lamp on the gas gauge (through the emergency flasher unit's, which is powered through the emergency flasher switch).

If fuse 9 is blown, making bad contact in the holder, or the wires plugging into it on the back of the fuse panel are corroded and not making great contact, that would affect the gauges, brake lights, and the brake indicator, and make the generator light behave wonky.

And that's just the protected side of fuse 9!

As far as throttle response, the supply side of fuse 9 branches off and goes back to the relay board and feeds 3 things: Coil power for the "Power Supply" relay, coil power for the Heater Fan relay, and terminal #15 on the ignition coil.

Eesh...Fuse 9 is really important.

Love the info. Thank you so much. Time to check fuses or lack there of. I may have bumped one or two with my head being under the dash working on the switch. The plastic cover plate has been gone, not lost, for a couple of years now. Need to gather up some replacement fuses first and see what is going on. Better yet, I have been meaning to replace the fuse box with a Jwest fuse box instead.
This is what I love about this site. The wealth of specific knowledge is better than any manual available. Options, shortcuts and true experience in every aspect an permutation you can think of.

[lierofox]

Well let's see... The generator light is fed power through fuse 9 to the light and then to the regulator on the board in the engine bay, fuse 9 also feeds the gauge indicator lights, several gauges themselves (including the tachometer), the brake lights, AND the brake warning lamp on the gas gauge (through the emergency flasher unit's, which is powered through the emergency flasher switch).

If fuse 9 is blown, making bad contact in the holder, or the wires plugging into it on the back of the fuse panel are corroded and not making great contact, that would affect the gauges, brake lights, and the brake indicator, and make the generator light behave wonky.

And that's just the protected side of fuse 9!

As far as throttle response, the supply side of fuse 9 branches off and goes back to the relay board and feeds 3 things: Coil power for the "Power Supply" relay, coil power for the Heater Fan relay, and terminal #15 on the ignition coil.

Eesh...Fuse 9 is really important.

Love the info. Thank you so much. Time to check fuses or lack there of. I may have bumped one or two with my head being under the dash working on the switch. The plastic cover plate has been gone, not lost, for a couple of years now. Need to gather up some replacement fuses first and see what is going on. Better yet, I have been meaning to replace the fuse box with a Jwest fuse box instead.
This is what I love about this site. The wealth of specific knowledge is better than any manual available. Options, shortcuts and true experience in every aspect an permutation you can think of.

I end up learning more and more about my own car while I'm offering help to others, as far as I'm concerned it's win-win! Even if my suggestions turn up dead wrong, it's still fun to brainstorm over the possible cause.

I ended up getting the Jwest fusebox a little while back because of how corroded and damaged my fusebox had become... and getting tired of picking fuses up off the ground every few weeks when my shoe brushed against it. It's a very good investment, and if you replace the fuses with ATO circuit breakers, you don't have to worry about being caught in the situation where you're in the middle of nowhere, accidentally short something out, and have no fuses left. Just reach down and push the button back in. (Or you can really splurge and get the self-resetting type. I went with manual-reset. Slightly more work, but it just felt safer.)

[drem914]

Well let's see... The generator light is fed power through fuse 9 to the light and then to the regulator on the board in the engine bay, fuse 9 also feeds the gauge indicator lights, several gauges themselves (including the tachometer), the brake lights, AND the brake warning lamp on the gas gauge (through the emergency flasher unit's, which is powered through the emergency flasher switch).

If fuse 9 is blown, making bad contact in the holder, or the wires plugging into it on the back of the fuse panel are corroded and not making great contact, that would affect the gauges, brake lights, and the brake indicator, and make the generator light behave wonky.

And that's just the protected side of fuse 9!

As far as throttle response, the supply side of fuse 9 branches off and goes back to the relay board and feeds 3 things: Coil power for the "Power Supply" relay, coil power for the Heater Fan relay, and terminal #15 on the ignition coil.

Eesh...Fuse 9 is really important.

Love the info. Thank you so much. Time to check fuses or lack there of. I may have bumped one or two with my head being under the dash working on the switch. The plastic cover plate has been gone, not lost, for a couple of years now. Need to gather up some replacement fuses first and see what is going on. Better yet, I have been meaning to replace the fuse box with a Jwest fuse box instead.
This is what I love about this site. The wealth of specific knowledge is better than any manual available. Options, shortcuts and true experience in every aspect an permutation you can think of.

I end up learning more and more about my own car while I'm offering help to others, as far as I'm concerned it's win-win! Even if my suggestions turn up dead wrong, it's still fun to brainstorm over the possible cause.

I ended up getting the Jwest fusebox a little while back because of how corroded and damaged my fusebox had become... and getting tired of picking fuses up off the ground every few weeks when my shoe brushed against it. It's a very good investment, and if you replace the fuses with ATO circuit breakers, you don't have to worry about being caught in the situation where you're in the middle of nowhere, accidentally short something out, and have no fuses left. Just reach down and push the button back in. (Or you can really splurge and get the self-resetting type. I went with manual-reset. Slightly more work, but it just felt safer.)

Bad fuse, fixed that and reinstalled the switch and it came back to life.