colorado turn signal

[BK2LIFE]

The rear taillight of the Chevy Colorado’s are a 4 wire system similar to imports.
And I have new LED 3 wire lights installed.

I used a simple 4 wire to 3 wire convertor (AutoZone, like 12 bucks) and am having some problems with turn signals now.

Under some checking around, the Colorado’s don’t use turn signal or 4 way flashers, the computer controls the flashing.

When the running lights are switched on, they come on at the taillights.
When the brake lights are applied, the brake lights light up at the taillights.

When the turn signals are on, and the brakes are applied, the turn signal indicators (both left and right) in the instrument cluster both light up. Also the clicking noise (think turn signal flasher relay) stops making noise when the brakes are applied with the turn signals. But let the brakes off, and the clicking noise comes back, and the indicators work as normal.

So I get into the wiring and try different things, such as placing a resistor in line to add extra load to the turn signal/brake circuit, and also tried placing diodes in line to prevent brake circuit voltage to go upstream the turn signal circuit. Nothing works.

Now I could be so simple as to use brake lights that have 2 bulbs, one for brake, one for turn, and both for running lights, but that’s the cheap way out. I want to use the LED lights already fabbed into my truck.

I am sure there is a simple way to get around this problem, so please any suggestions greatly appreciated.

-james

[MonzaRacer]

Sounds like flasher issues partially(use electronic one and triple check grounds).
what year of Colorado, and see if you can post up the aftermarket light diagram your trying to install. I can get Colorado diagrams, with divorced lights each light usually have own circuit.

[MonzaRacer]

OK I see big issue for installer with lack of understanding, this truck runs the lights through the BCM (Body Control Module)
This could get sticky.
Also the turnsignal switch simply diverts power from which ever side you want turn signal flashing on THROUGH the flash on most cars.
This vehicle flashes through the BCM.
I will work on a fix, but no promises cause it may cause a MIL to come on with code in BCM.
The BCM is going to look for the resistance of the bulb at all times, it will flash the brake light when you turn the switch appropriately. If it doenst see the right resistance,,, it wont work and you can break thing, expensive things.
Lee Abel
AFTERMARKET PERFORMANCE

[BK2LIFE]

The BCM is going to look for the resistance of the bulb at all times...



Right now the 4 wire Chevy Colorado rear taillight wiring is going into a "trailer" style 4 to 3 wire converter. I have standard 1157 bulbs hooked up to it now, which should be same if not similar resistance to the stock bulbs. So the BCM should not be seeing a different style bulb/resistance. BUT, (lol there is always a but isn’t there?) the factory wiring going into the trailer converter might be seeing a voltage drop/less resistance due to the current going through the diodes inside the converter.

I picked up some 50ohm 10 watt resisters and will try wiring them into the circuit to give extra load to the tail light circuit. 50ohm should simulate the added electrical load of an attached trailer.

[BK2LIFE]

found this diagram on the net, and got the pieces and will try it out tonight.



Here is a circuit you can build in about 45 minutes, and it costs 6-8 dollars in parts besides the universal 4 pin trailer harness.

Truck connections on left side, 4 pin trailer harness on right

From LEFT BRAKE LIGHT____(+D1-)___(+D2-)___(+D3-)___
From LEFT TURN LIGHT______________(+D4-)___________]__YELLOW____

From RUNNING LIGHTS__________________________________BROWN____
From CHASSIS GROUND_________________________________WHITE_____

From RIGHT BRAKE LIGHT___(+D5-)___(+D6-)___(+D7-)___
From RIGHT TURN LIGHT_____________(+D8-)___________]__GREEN_____


D1-D8=6amp 50volt silicon diodes radio shack p/n 276-1661 (you'll need 2 packages each pkg.=$2.49)
Instructions:
1. Cut and solder D1, D2, D3 together end to end, Cathode to Anode.
(Cathode is Negative and is the end with the silver band.) I recommend a hook splice solder joint, not offset splices.

2. Solder D4 cathode to D3 cathode, and then solder those to the YELLOW wire of the 4 pin harness.

3.Repeat steps 1 and 2 for the D5, D6, D7 bank, and then D8 cathode to D7 cathode.

4. Solder the GREEN wire of the 4 pin harness to the D7, D8 Connection.

5. Solder wire tails to each input to splice into your Vehicle. One on each: D1, D4, D5, D8. These go to the turn signals and brake lights on each taillight.

6. Tape over all connections, then tape the left wires and the right wires to bundle them.

7. You'll splice the wires as follows:

Truck wire harness color

Yellow wire = left turn signal (D4)

[BK2LIFE]

So I made the above “circuit” and installed it…
And the left side turn signal works perfectly. Brakes on or off the turn signal flashes at the correct speed.

Now the right signal, having the exact same “circuit” blinks normal speed with no brakes applied, but when brakes are applied, the lights flash at a double time, or same speed as if a bulb was burnt out.

I find this a bit weird, as it’s the same circuit as the drivers side, same resistance, same diodes, etc..

What I did not try was installing a resister in line. I will do that tonight.

Also the four way flashers flash at the correct speed now, both with brakes applied and not applied.