Brake light help

[KO]

I have a 1993 Honda DRX that is setup to tow 4 down. I used this forum several years ago to determine how to set up brake light system using diodes (I think the wiring suggestion required 5 diodes - but then again maybe three).

My issue is every time I drive the car and hit the brakes - the brake light stay on. The only way to turn off is to physically take off the power side of the battery.

Any help or ideas in fixing this problem?

[enblethen]

lanerd used the same ones I have.
Diode packs

[KO]

Thanx for replies. Good info. I will let you know what I find out.

[lanerd]

enblethen wrote:
I would only replace the diode for the brake lights not all of them. For testing purposes, you could swap out one of the turn signal or taillight diode pack with the one for the brake lights.

If one has failed, what's to say any of the others won't? May have been a bad bunch to begin with. Much safer to change all at the same time....diodes are cheap.

Posted By: j-d on 03/29/15 07:05pm

What about these?

Can somebody please answer these questions I have about using Diodes in this application?

1. Which end points toward the Bulb? The diodes I use have two inputs (one from mh, one from toad) and one output that goes to the bulb.

2. There's apparently a built-in voltage drop of 0.7 VDC. Does that affect the intensity of the light (noticeably)?None

3. If a diode fails "Open" all that happens is the light doesn't light, right? Yes

4. But what happens if a diode fails "Shorted?" Seems to me a shorted diode creates the feedback-to-towed-vehicle issue we're trying to avoid.Exactly

[enblethen]

You need more then one diode per light circuit. It is so much easier just to buy the diode pack from Roadmaster or Blue Ox.
Diode installation detail

[j-d]

What about these?

Can somebody please answer these questions I have about using Diodes in this application?

1. Which end points toward the Bulb?

2. There's apparently a built-in voltage drop of 0.7 VDC. Does that affect the intensity of the light (noticeably)?

3. If a diode fails "Open" all that happens is the light doesn't light, right?

4. But what happens if a diode fails "Shorted?" Seems to me a shorted diode creates the feedback-to-towed-vehicle issue we're trying to avoid.

[enblethen]

I would only replace the diode for the brake lights not all of them. For testing purposes, you could swap out one of the turn signal or taillight diode pack with the one for the brake lights.

[lanerd]

First thing I would do is replace the diodes.

Ron

[enblethen]

Sounds like you are missing diode to prevent backfeed into toad.
Roadmaster wiring diagram.

[Healeyman]

KO wrote:
Any help or ideas in fixing this problem?

HERE is a schematic for installing diodes into the tail light circuits.

This diagram is labeled for my Miata, but should be electrically the same for your car.

If you have a Radio Shack (still open) near you, they have a 4 pack of 6 Amp. diodes for $3. They are perfect for this application.

Tim