E brake light dim on speedometer

[jalexquijano]

As i previously informed i disconnected the female plug from the male middle switch of the proportioning valve and the low dimming light dissapeared.  I managed to spray electrical contact cleaner and brushed the tip of the male and female connectors and the light still shows up when plugging it back. What test should i perform now?

[cgsheen1]

22 hours ago, jalexquijano said:

As i previously informed i disconnected the female plug from the male middle switch of the proportioning valve and the low dimming light dissapeared.  I managed to spray electrical contact cleaner and brushed the tip of the male and female connectors and the light still shows up when plugging it back. What test should i perform now?

 

On 10/8/2018 at 7:32 PM, cgsheen1 said:

Do you have a multimeter?  You can test the switch (what you are calling the sensor) by removing the wire and testing for continuity between the male bullet connector and ground (the thing you have circled in red in the picture above).  It should have NO continuity (open circuit) if the shuttle inside is centered properly. 

If it has any continuity then:

- There is an imbalance in the brake circuits

- The switch is stuck and off the neutral position

- The switch is defective

The fact that the light only illuminates when the wire is attached shows the "fault" comes from the switch itself, not a ground fault in the wire.

The Factory Service Manual advises against repairing this device - but that was back when they were still available from dealers.  I would probably source another one - failing that, There's a cross section picture above (Figure BR-12 Warning Light Switch)  that shows how it could be disassembled.

 

On 10/8/2018 at 9:20 AM, jalexquijano said:

With an OHM METER check between THERE and GROUND.  Ohm meter should read "0" (no continuity).  If it does not read "0" then that part (the Warning Light Switch) is bad and you'll need to remove it and repair or replace it.

 

[jalexquijano]

On 10/8/2018 at 9:32 PM, cgsheen1 said:

Do you have a multimeter?  You can test the switch (what you are calling the sensor) by removing the wire and testing for continuity between the male bullet connector and ground (the thing you have circled in red in the picture above).  It should have NO continuity (open circuit) if the shuttle inside is centered properly. 

If it has any continuity then:

- There is an imbalance in the brake circuits

- The switch is stuck and off the neutral position

- The switch is defective

The fact that the light only illuminates when the wire is attached shows the "fault" comes from the switch itself, not a ground fault in the wire.

The Factory Service Manual advises against repairing this device - but that was back when they were still available from dealers.  I would probably source another one - failing that, There's a cross section picture above (Figure BR-12 Warning Light Switch)  that shows how it could be disassembled.

Well, this morninh i took my multimeter out and dial it to the continuity position. Placed red probe on the male bullet connector of the switch and the black one to the part that i circled in red. There was no beep which means that there is no continuity.  What could be wrong here if i already cleaned the female and male connector with a brass wire brush?

[cgsheen1]

The thing you have circled in red IS the male bullet connector...  Test between there and GROUND (battery "-")

(but, this is all just to absolutely verify that the switch is bad.  It is.  Just replace the damn switch...)

[Patcon]

3 hours ago, cgsheen1 said:

The thing you have circled in red IS the male bullet connector...  Test between there and GROUND (battery "-")

(but, this is all just to absolutely verify that the switch is bad.  It is.  Just replace the damn switch...)

Then bleed both circuits!!!

[jalexquijano]

Hi,

Just tested with black probe on negative battery terminal and the other on the bullet male connector. No beep meaning no continuity. However if i place the red probe on the bottom of the nut of the connector it does beep which means there is continuity. 

[w3wilkes]

In the female connector to the male connector on the switch is there some stray crap that may be hitting the top of the switch giving a small short in the circuit or maybe is the female connector pushed on too far? If you just set the female connector on the male connection of the switch is the light still on dim?

[Patcon]

I apologize for the orientation but it displays properly until I download it

This is the switch disassembled. The part at the bottom of this photo has the bullet connector on it. The center copper electrode is isolated from the outside shell with a plastic sleeve

Like this

You can see the bottom of the sleeve in this picture. If you have continuity from the bullet connector to the hex head on the sensor then there is corrosion bridging over it or there is a crack that has formed in the isolating sleeve. Like cgsheen1 said you will need a new switch if this is the case. This switch is NLA! You would have to find a suitable replacement and it might need cleaning internally. This switch was never supposed to be serviced, so extra caution is required. It is difficult to get it disassembled and reassembled correctly

[jalexquijano]

On ‎10‎/‎21‎/‎2018 at 12:03 PM, w3wilkes said:

In the female connector to the male connector on the switch is there some stray crap that may be hitting the top of the switch giving a small short in the circuit or maybe is the female connector pushed on too far? If you just set the female connector on the male connection of the switch is the light still on dim?

Ill check on that. I did noticed that when i started driving the car the light randomly dissapeared but came back again when i parked the car. Really weird. Mean i can live with it but it should go off all the way.

[jalexquijano]

On ‎10‎/‎21‎/‎2018 at 4:33 PM, Patcon said:

I apologize for the orientation but it displays properly until I download it

This is the switch disassembled. The part at the bottom of this photo has the bullet connector on it. The center copper electrode is isolated from the outside shell with a plastic sleeve

Like this

You can see the bottom of the sleeve in this picture. If you have continuity from the bullet connector to the hex head on the sensor then there is corrosion bridging over it or there is a crack that has formed in the isolating sleeve. Like cgsheen1 said you will need a new switch if this is the case. This switch is NLA! You would have to find a suitable replacement and it might need cleaning internally. This switch was never supposed to be serviced, so extra caution is required. It is difficult to get it disassembled and reassembled correctly

Yes i guess its better not to mess with it. I was thinking of removing that hex nut and cleaning the innards but it i need to pull all the proportionate valve out from the car hen its risky business.

[Patcon]

4 minutes ago, jalexquijano said:

Yes i guess its better not to mess with it. I was thinking of removing that hex nut and cleaning the innards but it i need to pull all the proportionate valve out from the car hen its risky business.

To clean the switch it really has to be off the car. That means all the brakes would needed bleeding after that. You would also have to protect the paint on the frame rails. The brake fluid will remove it fairly quickly. You really can't clean it by just removing the sensor post.

[jalexquijano]

Maybe i should try bleeding the brakes first