Very simple question with a simple answer.

The wire you are cutting will be connected to a relay.

When the relay is at rest, the wire cut will be connected as if it was OEM.

When the relay is charged bu 12V(+) from the orange wire, it will disconnect the OEM Wire and sent a 12V(+) to the HU making it think it was in reverse.

Does it make sense?

1 relay is enough. You can also get a rocker switch with a LED built in for a simple setup.

 

My head hurts. So is this really a one wire deal?
I can build computers, but this is way above me.

 

Yes. This can be a one wire deal with the help of a relay and a +12v source. If you review the schematic I posted earlier in this thread and read the comments in ISTUNDRA's last post, you should have no problems at all. The biggest part of this is modification is removing the HU. Even that is not a big challange if you read and follow the posts here.

If you are not interested in a switch with a light (however, you may be able to find one with a light) and can find a SPDT (single pole double throw) switch you can eliminate the relay. I just used parts I had in my cabinet. If you choose to do this, the arm of the switch will be attached to the HU side of the Blue wire, the NO contact is attached to the 12v source and the NC contact is attached to the harness side of the blue wire. In the NC position, the switch acts only as OEM with no modification. When you press the switch, you then break the OEM configuration and supply an alternate 12v source to the head unit which then thinks the car is in reverse, although it is not.

I hope this is clear for you.

 

Yeah it is simple. 1 wire to cut, 1 wire to TAP, 1 wire to ground, and 1 wire to the switch and 1 wire from the switch.

Post here if you are ready and i can post the pin-out.

 

can anyone provide precise details? as to which wire to cut and things...thx

 

Blue06GS,

I am not certain how much more or what type nfo you need. All that should be required is here in this thread. Airwolf originally described this mod cutting the blue and the gray wires. This was untested at that time. I then reviewed the Lexus schematics and found that this could be done with the blue wire only. I then tested the modification and have performed it in 3 different IS cars. All worked the first time with no associated problems in other areas.

If you will follow the directions I posted on 9-29-06 and review the .pdf file I attached, it will work perfectly. There has been other discussion since that post regarding variations to not include an indicator lamp in the switch, to use a switch which uses own 12v source which it switches,and most recently I posted on how you can do this without a relay. To my knowledge, only my first posting has been actually proven to work. I am sure that as long as you use the information that has been posted in this thread you will be fine.

The concept is to just remove the trigger 12v coming from the "blue" wire (OEM) and replace it with an alternate 12v source to turn the camera on while driving (not in reverse). This can be done several different ways involving a switch or a relay and may include an indicator bulb or not. The information is here in ample detail to make this modification safely. I hope this helps. If you have a specific question you may PM me and I will try to help you.

 

i dont think the pdf works anymore...maybe you can repost it?

 

I just checked it and it opened fine. I also went to a different computer and was able to open it as a guest.

Is anyone else having a problem opening it? I assume you do have Acrobat reader or other program which will read .pdf files?

 

Worked fine for me as well.

 

I think it will be best to rate each DIY by skill level. I have noticed alot of members here plan to complete the DIY with positive results but some do lack experience. The disclaimer is always good to protect not only the author of the DIY but the site itself.

I personally always use the DIY as a reference and triple check everything before i make any incisions to the car.

 

This sounds good in theory, however there are no standards to set the DIY skill levels. You are correct in that what is a comfortable mod for one person can often present a challange to another. With there being no set standards other than those which could be set subjectively by any one of us, I believe the best option is still a good description, diagrams, photos and trial and error experience as posted here remains the best way to present this information IMHO.

 

Very true. Didn't mean to hijack but personally.. If i were to rate this DIY.

1 being very easy
5 being difficult

I would rate all of the electrical connections to be a 2. The only hard part is removing the vent from the dash.

 

OK - my car is all torn apart and I would really like to do this hack. But, there are a few things I just cannot figure out from Lexellent's diagram. I have no interest in having an LED. But, I went ahead and purchased DPDT relay from RadioShack (pn 275-218... same one suggested in the diagram).

The first few steps are easy:

1. Cut the blue wire.
2. Relay Pin 1 = blue wire from loom
3. Relay Pin 3 = blue wire from Nav unit
4. Relay Pin 5 = tapped orange wire (tapped, not cut like the blue wire)
5. Relay pin 7 = one side of the switch (does it matter which side?)

It is here where I get confused. There are two steps left... pin 8 of the relay and the other side of the switch.

Since I'm not using an LED, I can't really figure out where to connect the switch. Do I connect it to pin 5 also (so pin 5 will be connected to two wires... the orange one and one side of the switch)? And, what is pin 8 of the relay connected to exactly? It says it needs to be grounded. So, I need to ground it to the frame somewhere?????? Where did you ground yours?

Thanks for the quick response... I'd love to put my car back together ASAP.

 

Pin 7 is one side of the switch, Pin 6 is the other side. (There will be two connections on pin six.)

Exactly as in the diagram, minus the wires to the LED (green and gray). All other connections must be the same.

Pin 8 for the earth - White with black stripe is earth on Lexus. You should be able to pick one of these up or as you say, to the frame.

 

I see - I thought I read somewhere above that if you aren't using the LED you'll only use "one side of the relay". But, I must have misinterpreted that. So, the orange wire will still go to BOTH Relay pin 5 and Relay pin 6. Pin 6 will also have one side of the switch. Pin 8 will be to the white w/ black stripe.