brake light is figity

[yARIC008]

When i push my brake pedal the lights come on initially. If I'm only braking gently the light will usual turn back off when i maintain constant gentle braking push on the pedal. If i push harder and start getting some actual resistance on the pedal the light will come on and stay on like normal. I replaced the BOO switch attached to the pedal arm and it didn't seem to change it or make it better at all. Other vehicles and other vans don't seem to have this problem from what I can tell from being behind them or in them.

Anyone have this problem or have any idea how to adjust/fix it. The way it is now, I could gently brake the van to a stop and have the brake lights only flicker on once.

 

[franklin2]

The only way to fix it is to put a lighter spring in the brake switch. Did you see how it worked? The pin in the pedal arm is actually too small for the rod going to the booster. So it has a lot of slop in it. They take advantage of this slop, and mount the brake switch in a way that when the slop is taken up, it activates the switch. It's a pretty hokey way of doing it, but they had this design for years and years on all their cars and trucks.

 

[cnelson]

The light on my 91 would come on when the brake fluid got low.

 

[yARIC008]

The light on my 91 would come on when the brake fluid got low.

I believe you are talking about the emergency brake light. I was referring to just the tail lights. The emergency brake light comes on when the reservoir sensor detects no fluid or if the emergency brake is on and I think if the vacuum switch detects low vacuum.

 

[yARIC008]

The only way to fix it is to put a lighter spring in the brake switch. Did you see how it worked? The pin in the pedal arm is actually too small for the rod going to the booster. So it has a lot of slop in it. They take advantage of this slop, and mount the brake switch in a way that when the slop is taken up, it activates the switch. It's a pretty hokey way of doing it, but they had this design for years and years on all their cars and trucks.

Hm.. guess I'll go take a look at it. Anyone happen to know where you might be a lighter spring for it?

 

[79jasper]

IIRC, there's a secondary pressure switch on the Rab's valve.
Mine does it also.

Are your rear brakes adjusted good?


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[f-two-fiddy]

My IDI got better with a new switch. The gasser does the same as yours.

 

[ironworker40]

My truck does the same thing as op posted. Has anyone come up with a cure for this? It causes the trailer brakes to shut off too soon also.

 

[3Kp]

I was having the same problem then finally rear brake lights quit all together. So I put in a new switch on the pedal still no luck. I started to look at the wire harness and found one of my wires was starting to break off and the other did break. So I cut off the harness and put on 2 female connectors. Problem solved for me! Check the wire harness for damage.

 

[dunk]

Try a new switch, should only be a few bucks. Likely dirty/worn contacts or slop in the switch/spring/etc. Ford literally used this switch for over 30 years, starting in 1967 with the switch to dual circuit brakes.

 

[ironworker40]

I did put a new switch on it and it still does the same thing. I was hopping that maybe someone figured out a cure for this. No wire damage on mine either

 

[79jasper]

Rear brakes adjusted up tight?

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[franklin2]

I did put a new switch on it and it still does the same thing. I was hopping that maybe someone figured out a cure for this. No wire damage on mine either

It's the way the switch is designed. You are going to have to quit riding your foot on the brake, especially when towing with a trailer. If your foot is on the brake pedal, push it down and use the brakes. If you do not need the brakes, take your foot off the pedal. There is no way around this, it's the way the switch works.

 

[OLDBULL8]

I use some pretty nasty words when following someone that rides the brake peddle.

 

[ironworker40]

It's the way the switch is designed. You are going to have to quit riding your foot on the brake, especially when towing with a trailer. If your foot is on the brake pedal, push it down and use the brakes. If you do not need the brakes, take your foot off the pedal. There is no way around this, it's the way the switch works.

I never ever ride my foot on the brake. The brake lights shut off and the electric trailer brakes also shut off when the brake pedal pressure is reduced slightly. So in order to keep brake controller active you have to keep a heavy foot on the brake pedal, which on a 5 speed if you downshift its hard to do. Moron drivers are always running up on me because they follow the to close and the brake lights go out too soon. If you test most other vehicles the brake lights will stay on until the brake pedal returns to the full up position but will remain active throughout the pedal travel.