emergency brake light dim?

[RobsRR]

My emergency brake light is dim. It turns bright when e brake is engaged as it should. I did switch all the dash lights to leds a year ago and love it. They have been working fine. It was never dim before today. Any thoughts? 71 Roadrunner

 

[mccoymail]

Interested because I have the same issue. LED’s worked for about a year, now dim always.

 

[Nacho-RT74]

Unplugg the brake fluid distributor wire to check if something changes

 

[RobsRR]

Unplugg the brake fluid distributor wire to check if something changes

 

[RobsRR]

Yes I unplugged the wire and it is no longer lit. ?

 

[Nacho-RT74]

The brake light on cluster is not just emergency brake pilot light but also a brake fluid pressure failure warning light. You can get some slight pressure failure somewhere ( or switch failure ). Are the master cylinder brake fluid deposits fill the same? You could notice one of them getting emptied and the other one getting overflowed

 

[RobsRR]

Interesting. I just did a disc brake conversation about a year ago Dr. Diff 11.75. The fluid looks good equal on both sides of reservoir. I wonder if the switch is the issue?

 

[Nacho-RT74]

Mmmmm disc brakes setups uses diff pressure than drum brakes and a diff proportioning valve due this reason!

Switch is activated by a piston which moves in between both brake fluid circuits ( rear and front which are isolated one from the other ) if some of them unbalances due a pressure failure the piston moves and turns on the light

( not saying that is the reason but, maybe... )

 

[RobsRR]

I will check with Cass doctordiff Monday we did change the proportioning valve for the disc brake setup

 

[RobsRR]

I will check with Cass doctordiff Monday we did change the proportioning valve for the disc brake setup

Thank you for all your input

 

[Nacho-RT74]

Not just the prop valve but also master cylinder. Disc setup gets diff pressure and fluid volume between rear and front beginning at the master cylinder.

Once again, NOT SAYING is that but maybe! Thinking out loud

 

[kiwigtx]

Thank you for all your input

Have you tried a jumper wire between the brake lines at the master cylinder and ground while the light is in the 'dimming' mode?

It might be a simple grounding issue if a proportioning valve was changed out.

 

[Nacho-RT74]

Miss that ground should be like unplugg it. Ground issue at distributor Shouldn't cause that effect. Is not like a bulb trying to light up and affecting another circuit able to provide the missed ground by the bulb

 

[RobsRR]

Miss that ground should be like unplugg it. Should cause that effect. Is not like a bulb trying to light up and affecting another circuit able to provide the missed ground by the bulb

 

[RobsRR]

The last two posts are not clear to me. Can you reexplain. I am open to try any suggestion. I am not following. Thanks in advance.

 

[Nacho-RT74]

sorry, I edited my previous reply.

He is suggesting the brake fluid distributor is not getting chassis ground because tipically dimming lights are linked to ground failures. But that kind of symptoms are present on different circuits linked to the same ground. Let's say you turn on parking lights and fender turning lights begins to dim. They are diff circuits but linked on same ground through the 1057 bulb in front signals ( 1057 bulb should be dimming too for turning, just harder to see with parkings on ). The chassis ground missed by front parking light could be being sourced by the fender turning signals or even rear lights, so that small current glows those filaments.

 

[RobsRR]

sorry, I edited my previous reply.

He is suggesting the brake fluid distributor is not getting chassis ground because tipically dimming lights are linked to ground failures. But that kind of symptoms are present on different circuits linked to the same ground. Let's say you turn on parking lights and fender turning lights begins to dim. They are diff circuits but linked on same ground through the 1057 bulb in front signals ( 1057 bulb should be dimming too for turning, just harder to see with parkings on ). The chassis ground missed by front parking light could be being sourced by the fender turning signals or even rear lights, so that small current glows those filaments.

Okay I get it. Thanks

 

[72RoadrunnerGTX]

Old thread, but FYI, Dakota Digital gauges for 71-74