[zpaul]

Originally Posted by daless2

Hi Zpaul,

I have some information for you that might help. Some of this info is Fact, some I highly suspect to be fact but cannot directly prove.

I can tell you as fact that the Turn Signal/DRL Lights on your Tundra using the Auto Light Mode SHOULD turn OFF when the Auto Mode Turns on the headlights.

In other words, yours are not working as they should be with this design.

I tried to verify this via the electrical diagrams, but could not make that determination based on the diagrams alone. One never knows what goes on inside the computer black boxes. At least not all the way.



This morning I called a young man who lives nearby who I had help install this DRL modification. He has Auto Mode Lights. I asked him if I could stop by and run some tests on his truck to see how the DRL/Turn Signals lights work when the Auto Light Function was used.

Long story short, He told me to drive over to where he works, gave me the keys and let me test away.



His Tundra is a 2007 Limited Crew Cab, with Auto Light Function and came from the factory WITH OUT DRL. He and I installed this DRL Modification several months ago.

On his truck, with ignition key “ON”, and the headlights are OFF, the DRL/Turn Signals are “ON”. This is goodness.

When the Headlights are Turned ON, either by the switch, or by the Auto Function (I had to cover the sensor to make this happen) the DRL/Turn Signals Do Indeed Turn Off, as they should.

What this tells me is that this design does work, even in Auto Light Mode.



What I Believe


Something is probably wrong with your installation, most likely involving Relay “B”.


When Relay “B” is at REST (Not energized because the headlights are OFF) it provides a ground to the DRL Relay. This turns the DRL/Turn Signal bulbs “ON”.


When relay “B” is “Energized” (This happens when the headlights are ON) the Ground path to the DRL relay is broken, or “Opened”, effectively turning the DRL/Turn Signal lamps “Off”



To be more specific I would be looking for a problem in these areas.


1) Is Relay “B” Good? It is rare but I have seen new relays fail right out of the box. To test, swap relay “A” with relay “B”. See if the DRL still work. If not, the relay is bad.

2) Check the wire going from Pin 86 on Relay “B” to the left front headlight.

Make sure this tap is mechanically and electrically sound near the headlight. If it is not, Relay “B” will never energize when the headlights are on. When Relay “B” is energized, it shuts off the Ground Signal going to the DRL Relay, which turns the DRL/Turn Signals Off.

3) Make sure there is NO WIRE connecting pin 87 on relay "B" to anything at all. This Pin is not used and cannot be connected to anything, especially not to a ground.

4) If you are using a relay socket to plug your relay into make sure the female connectors in this socket are sound mechanically and electrically. It wouldn’t be the first time one of these failed.

5) Double check all your wiring and electrical connections.

I am convinced something is preventing relay “B” from working. Time invested in checking this out should be worth your while.

Hope this helps you out my friend. If it doesn’t, I’m more then willing to continue to help trouble shooting this with you.

Have a great day,

Frank

Frank, I finally found the time to go back and fix it. Your wiring instructions were modified for my install, that is why it was not working. The wiring was done without running it to the headlights plus one relay was eliminated, that caused all the problems. But thanks for your replies and help.
It finally works like it should.
For some reason I do not see much Tundras with DRL in Baltimore area.