Just picked up a used SnugTop shell, with the Third Brake Light built in. The previous owner snipped the two lines that come from this light and just left blank ends. I was going to tie in to one of my tail brakelights, but realized that those same lights are also the turn signal and would probably force the third brake light to blink with the turn signal.

Has anyone wired one of these puppies up? I know it is probably very simple and easy to do, but I need to make sure we do it right.

Thanks in advance,

Mike

 

I have the same problem. I was thinking about tying into the trailer lights, but I don't know which wires to use. With all of the knowledgeable people on this board, I find it hard to believe that no one has responded to your post.

 

As you have discovered, if you only connect one brake light to the third light, then it blinks when the turn signal is on.

The way to connect the third light is to connect both brake light wires to the third light but this must be done with the use of diodes in each connection to the third light to prevent the flow of electricty between brake lights. A diode allows current to flow in only one direction.

Diodes are available at Radio Shack. Get a couple that are 12 volts or more, at least 1.5 amps... about 5 bucks for two. There will be an arrowhead on them showing which way the current flows. Wire them into each brake light wire so that the arrow heads point towards the third light. Tie the ends together, run a single wire to your third light, and you are done.

Sorry I didn't answer eariler... just joined.

 

I have the same problem. The previous owner had the brake light blinks with the left turn signal. What I'm looking for is a spot, possiblly under the hood, where I can tap into the power for the brake light on the cab. The dome light in the bed cap is also tapped into the tail light so I have to turn on the parking lights to get the dome light on. I'm going to be pulling a wire for the dome light because it's a pain to have to turn on the parking lights to turn it on. I'm hoping to pull these wires at the same time.

DF

 

Check your latest J.C. Whitney Catalog. They sell a converter which allows you to connect a third brake lamp, eliminating the third brake lamp from flashing when you utilize the turn signals. The cost is around $5.00 plus shipping. The converter includes step-by-step instructions. This is what I utilized to connect my third brake lamp (I have a Glasstite topper). After installation, the third brake lamp will flash when you utilize the emergency flashers, but I consider this to be an added safety feature.

 

I believe you will find a GREEN wire in the harness by your trailer hitch that is folded and taped over, and not connected to anything. That is the wire for your cap break light. I ordered the trailer tow package and the wire was there. I don't know if its there on the connection for the flat 4. If after connecting the wire, the brake light doesn't work, try reversing the wires. That is what I had to do with my cap. Works great. I hope this will help.You don't need diodes. I hooked the interior light to the power source under the hood with an inline fuse so it will work anytime. I ran the wires up through the back left side, up into the cap. Good luck.

 

Interesting, Thad... I checked my 2001 SCrew (June build), and the green wire is not present in the wiring at the trailer hitch. What I have is

Yellow - left stop/turn
green - right stop/turn
brown/white - tail lights
white - ground
blue - electric brake feed
orange - trailer battery feed
black/light green - backup lights

However, if that wire _is_ present in the harness then you may be onto something. According to the trailer tow wiring schematic, the green wire to which you refer connects the brake light switch to the brake controller unit as input to the unit. Thus, if the wire was rung all the way to the hitch, then indeed you would have a clean brake light source with no worry about turn signal interruption.

 

If you follow the hitch plug wiring back about 18 inches, you will see another set of covered wires that T off into another direction, behind the drivers side rear wheel. It was in there. I had to open the plastic wire cover a little and it was coiled back on itself about a foot from the T. I hope no-one makes a mess of their wiring looking for it. Your service rep can probably tell you exactly where it is.

 

Thad,

If there is 2 wires coming from the 3rd brake light on my topper, does one of them go to the green wire and the other go to the white (ground)?

 

The two wires should be power and ground.

DF

 

I did not use a ground wire from the harness, but that would probable work as well or better than running another to the frame or some other ground.
You may have to reverse them when hooking up for some reason. Did you find the wire?

 

I should have mentioned, I ran the wires through the left rear post and bundled the wires into a short piece of garden hose to keep things neat. Then out to a flat 4 plug, and then to the brake and interior light. That way if I want to remove the cap I just unplug the wires and its off. I put them all into the back corner of the cap and hot glued them out of the way so they don't flop around. It works great.

 

Thad,

I found the green wire that you were refering to. It was in the wire bundle going to the drivers side tail light. It was sticking out of the plastic wire cover and taped back to the cover. I also dropped the spare tire and found where the trailer lights ground to the frame so I won't need to splice into the wire. Hopefully I won't be to busy at work Thursday night so I can finally get this thing done. Thanks for the info!

 

I found the wire tonight too. I disconnected the hot side of the cap brake light from the left brake light and used a Posi-Lock connector to hook up the light. Took me about 30 min. Thanks for the tip Thad

DF

 

Your welcome, glad I could help.