Brake warning light

[mroberts]

Just bought an '88 Sportswagon.

PO has wired up a third brake light, but every time I hit the brake, the brake warning light comes on.

What triggers the light, and any tips on what to do ? He said it only started when he added the third lamp. Obvious solution is to remove the third lamp, but Canberra drivers suck, so I'd liek to keep it, if I can understand why it's coming on.

Thanks.

[Subafury]

the brake fluid warning comes on? if thats so it is triggered by the depth floatie in the resevoir. but that couldnt be triggered by ur situation.
i spose im no help then.

[steptoe]

my Brumby brake warning light comes on whenever a trailer and lights are hooked up. By adding a third light you may have altered somethin'. But then my third centre light don't cause any probs?

[redskin]

Just bought an '88 Sportswagon.

PO has wired up a third brake light, but every time I hit the brake, the brake warning light comes on.

What triggers the light, and any tips on what to do ? He said it only started when he added the third lamp. Obvious solution is to remove the third lamp, but Canberra drivers suck, so I'd liek to keep it, if I can understand why it's coming on.

Thanks.

The light should be triggered by the brake light switch under the dash and behind/above the pedal, as are the tail lights, it may be that he has tried to splice into one of these wires, rear loom runs along the drivers side, it's a safe bet to start there, behind the rear tail light. I've come across this problems a few times, it's usually due to shoddy trailer wiring, to be sure, disconnect the third light from it's join, if the problem stops, his connection was causing a short, if not the short could be further up or you really don't have any brakes, has anybody checked?

[BaronVonChickenPants]

My MY did the same thing when a trailer was connected, I figured the light is based on some sort of metering circuit and comes on when current draw is outside specific parameters.

Don't know if this helps, but may give you a rough idea.

Jordan.

[Fang]

Hey MRoberts - are you referring to the "Stop Lamp" light just below the instrument cluster? That is supposed to light up every time you push the brake pedal and there is a blown bulb.

A wiring diagram might be your friend.

[mroberts]

Hey MRoberts - are you referring to the "Stop Lamp" light just below the instrument cluster? That is supposed to light up every time you push the brake pedal and there is a blown bulb.

A wiring diagram might be your friend.

That's the one. I'm bidding on a manual on eBay, so I should have that soon.

or you really don't have any brakes, has anybody checked?

Fair point ... the car is so slow I may not have noticed the brakes don't work, the drivetrain losses may be what's slowing it down

[GTlegs]

Yep, sounds like a blown stop light bulb.

[maddog]

I had a similar problem in my 87 wagon - turned out to be the brake light detection circuit which is a small printed circuit board contained in the drivers side rear light assembly. It is hard wired into rear light assembly wiring loom and I 'fixed' it by replacing wiring loom with a spare that I had.
(I'm sure you could somehow simply bypass the circuit...any clues anyone?)

[Suby Wan Kenobi]

you can bypass it as they do burn out from time to time

[Cozmo]

Run the high stop / third light off a relay, so instead of drawing current directly from the existing circut, it can take it from the battery (and not cause the warning light to come on).