Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
What are the type bulbs you are using for the trailer turn signals? The normal type bulbs that is.
Sorry, I was out. Why didn't you answer my question?
What do you mean the trailer isn't part of the problem right now? So, you have the trailer unhooked and you still have problems with the lights on the truck?
Ok, yes than you have a short, the green wire should be for right trailer turn. The yellow is for left trailer turn. So, the problem is with the truck, you are correct.
So you have both trailer turn signal wires hot no matter which way you turn the truck turn signal switch to, either left or right.
Wait, why are you saying when you hook up trailers with incandescent bulbs the bulbs act up when they already act up with a trailer hooked up.
Any who how, I think you should double-check all of the bulbs on both the truck ad trailer and make sure they are the correct bulbs. At least the truck I the trailer is not yours.
The ground by the way for that trailer connector should be G302 located at the left side of the fuel tank.
Here is the wiring diagram, for what it's worth cause this is going to be a tuff one, but I'll help you through it.
Now I am no bulb expert but I believe the 1156 are single filament and the 1157 are two filament, plus I believe there is the 2057 and I believe they are an updated version of the 1157 but don't quote me on that one.
Check the voltages at them 2 fuses, the rt trlr st/turn and lt trlr st/turn , if you get the same results there, I believe you are looking at a faulty turn signal flasher module.
Yes, a power source will find ground through any source that it an and it will always take the path of least resistance. So, let's say for instance a wire was short circuited to another wire, the ground path could change from the first wire and take the second wires path, even if it happens to be a normally positive wire, it doesn't matter as long as it has a path to ground that is less resistance then the first.
That is why I wanted you to check all of the bulbs, cause with the wrong bulb in a socket say a single filament instead or a double filament, the power could possibly be touching the ground spot at the bulb as well as the power spot both at the same time and sending power back through the power circuit of let's say the parking lights and then head over to the other side and finding a ground through the turn signal on that side and back along the power wire back into the truck and so froth.
That is why I said to check all of the bulbs, that includes on the truck as well
Let me ask, are you using a metal ground when testing at the trailer plug or are you using one of the terminals in the plug as a ground for the test light?
Yes, an LED is a light emitting diode and voltage only flows in one direction.
Which relay, the "park lamp" relay? No, that is not part of the trailer turn signal circuit at all.
Do you know the name of it?
Are you sure it's a relay and not that module?
Well, that is the ground for the module. If the voltages are correct at them fuses I mentioned, then I don't think it has anything to do with that relay, module and/or ground G203.
So you are done, the ground was bad?
You can test the ground voltage drop in order to tell if it's loosing any voltage.
Hook up a dc voltmeter the positive lead as close to the ground wire on the trailer connector as you can, then hook the negative test lead to a good metal ground or on the battery negative post, to be sure. I have a 25 Foot wire I use just for that. Anyhow, when the voltmeter is hooked up, power the circuits and watch the voltmeter. It should read no more, than 0.2 volts. If it does that is the amount of voltage drop and how much that ground wire is loosing cause the ground will take the path through the meter instead or the wire if the meters résistance is lower and the wire will also measure how much voltage is flowing through the meter when it should be flowing through the ground wire. So, if the voltmeter reads anything over 0.2 volts, that 14 gauge ground wire isn't enough.
What was the voltage drop/loss along that 14g ground wire?
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