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Ask Gm Tech (Cam) Your Own Question
Gm Tech (Cam)
Gm Tech (Cam), Cadillac Mechanic
Category: Cadillac
Satisfied Customers: 29427
Experience:  GM Grand Master Technician 2007. 14 years experience.
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I have a 2008 SRX that had a turn signal go out. I found out

Customer Question

Hello. I have a 2008 SRX that had a turn signal go out. I found out how to remove the bumper to gain access to replace it. I purchased new LED bulbs and when they were installed, the turn signal still flashed fast. I got 8ohm 100w resistor and started to put it in parallel. I accidentally touched the positive to the flasher to ground (sadly while it was on). A short spark as I pulled it away.
The rear turn signal still flashes fast but the front is not getting a power. Before I made the booboo, it was supplying voltage to the turn signal. I have checked all the fuses under the hood but they are all good.
Any suggestions?
Submitted: 1 year ago.
Category: Cadillac
Expert:  Greg Jensen replied 1 year ago.

Well It looks like you have two bulbs in the front of that system one major and one repeater. however they are controllled with output from the Bcm and it shows no fuse between the two. So Based on your info it looks like you may have burnt up your out from the Bcm and you may have not replaced the bulb that needed replacement.

Customer: replied 1 year ago.
i asked for specifics. Every thing there is possibilities that I need to check. A) I know the turn signal was out because I quit working about a week before I got these bulbs and removed the bumper. I plugged the LED bulb in and it flashed. Everything is perfect. THEN, the computer sensed low current draw and tripped the "bulb out - quick flash." Now I have the rear turn signal flashing fast and the new LED bulb that is plugged in. To stop this "quick flash," I was installing a resistor across the positive to the LED and the ground. Before the connection was secure, the positive wire going to the right flasher touched direct ground. A spark ensued and the rear blinker continued to "quick flash." The front blink no longer blinked. I checked the positive wire again and what was a square(ish) power wave is now a solid ground.
Do you have assistance for this? Also, the image you sent me is very poor quality.
Expert:  Gm Tech (Cam) replied 1 year ago.

Hi there, I am Cam. Can I get your first name please?

With this issue happening and you replacing all the fuses, did you verify the wiring at the Body Control Module (BCM) is not shorted out? Power to the lights comes directly through the BCM as it controls the lighting from the fuses. If the BCM itself shorted out internally, this would be the result. So the first place to check is at the BCM, does it have any wiring that you can see is shorted? Does it have an odour to it?

Customer: replied 1 year ago.
My name is***** odor or any overheated or shorted wires that I see. However, I have not checked the BCM because I do not know where it is located. I also noticed this morning and afternoon that the interior courtesy lights are not working. I can push the button to turn on the map light but it will not come on when the door is opened or the key removed. I even tried turning the instrument cluster all the way up to activate the interior lights. Nothing. The instrument cluster dims like normal. Can you advise if the BCM would also cause this and where is it located?
Expert:  Gm Tech (Cam) replied 1 year ago.

Lonnie, yes it would. The Body Control Module (BCM) controls most of the lighting of the vehicle.

In this schematic you can see the signal lights.
The second link is the power feeds into the BCM.
Third is the panel to remove to get at the BCM and 4th is the BCM. Its directly under the steering column.

Customer: replied 1 year ago.
thank you. Your image was slightly larger so it made it easier to read. I now understand what the first guy was trying to say. I appreciate the quick response. Sorry for my delay.
What you have described sounds like it fits my issue. I will get this fixed.
This still leaves me with the issue of "quick flash" because I am using LEDs which draw a lot less energy (thus energy/fuel efficient). I was attempting (which lead to this fiasco) to put a load of 8ohm across the wires but that increases the amps from a meager ~0.15A to a whopping ~1.4A. This defeats the purpose of LEDs. When I get the unit replaced, is there a way I can disable or lower the setting to avoid adding the dead load.
Expert:  Gm Tech (Cam) replied 1 year ago.

While I have not played with LED's as much with exterior, Is there not higher quality ones that build in a resistor to mimic the load of a regular bulb?

Expert:  Gm Tech (Cam) replied 1 year ago.

Otherwise we need to put the resistor in line with the bulb to add to the entire circuit resistance.

Customer: replied 1 year ago.
I see in the diagram, it states that if I replace the BCM, it needs to be programmed. How do I do this or does a dealer have to charge me an extra $200?
You stated that if I didn't (or couldn't) get a different LED, i would need to add a resistor in SERIES with the LED. What size resistor would I need? I was told it would need to be 100W and be connected PARALLEL to LED (similar to a electrical splint).Finally, in the first image, it shows a trailer connector/provisions in the rear fuse panel. 1) Can you tell me where the rear fuse panel is located? 2) Can you provide me with this connector/provisions schematic (as stated on the first image)? 3) Can I temporarily run a wire from this connector to the front so I can have a working blinker?
Expert:  Gm Tech (Cam) replied 1 year ago.

ok the programming is not something you can do. It requires access to the GM programming server along with the programming tool.
For the resistor. Lets try your 100W 8 ohm resistor wired as pictured in the first diagram.
your rear fuse blocks are under the second row seat. There is a wire to each that goes to the rear lights. For now, We can use the wiring that runs from the BCM to the rear lights. They are in the brown connector. Pin 1 is left and pin 2 is right. Attached is the connector end view for the brown BCM connector.

Customer: replied 1 year ago.
The first image from the most message shows three wires going to the bulb. In my instance, I have 4 going into the turn signal housing. When you open this to replace the bulb, the wires split. Two go to the turn signal connector. The other two go to the fog lamp. I see that the turn signal connector has an option for a third wire but it is not connected; this would explain why only the high setting for the LED worked even though I successfully tested both settings (outside pins are bright LED and inside pins are low LED). I don't think it was a "mistake" by Cadillac so is there something else going on here? I am attempting to upload a picture I took. It may be hard to tell but the connector on the right is the turn signal and the left is the fog lamp. On the turn signal connector, there is a blue filler around the wires on the outer two pins. The middle one is empty. Is there a way to change the connector to fix this?
Expert:  Gm Tech (Cam) replied 1 year ago.

I am getting 2 different options, what is your VIN?

Customer: replied 1 year ago.
1gyee637680131264
Expert:  Gm Tech (Cam) replied 1 year ago.

OK it does not show the wiring inside the light as they classify that as an assembly. But on the matching connector that plugs into it, Dark blue is the left signal supply wire and dark green the right.

Expert:  Gm Tech (Cam) replied 1 year ago.

Any updates?

Customer: replied 1 year ago.
You are correct, the dark blue is left and the dark green is right. I was looking over the steps that I need to do in order to temporarily fix this issue. When you say "pin 2 on brown connector" is the right turn signal, is that from the BCM under the dash and not the fuse box?
The next thing I think could be an issue is this: if I connect power to the front blinker from the rear signal coming from the BCM, won't I ground that side too because the connector for the front light (dark green) is currently showing a hard ground?
Expert:  Gm Tech (Cam) replied 1 year ago.

The brown connector is indeed the BCM under the dash. IF you still have LED in the front, then it may show a dead ground, I would check and compare side to side and see what the other side shows.

Customer: replied 1 year ago.
I have checked the wires at the connector. The dark green from the BCM to the bulb (both LED and standard) and neither work because the positive wire has been grounded at the BCM. The dark blue shows a voltage when the blinker is on and nothing (not ground or positive) when the blinker is off.I have removed the LED and only using the standard bulb until I have fixed this problem.What I want to be sure of is, if I connect pin 2 of BCM brown connector to the dark green (power) wire for the front blinker, will it ground out through the BCM as well.
At this stage, I don't know what happened "to" the BCM except that one wire touched ground. Now it doesn't control half the car and the dark green wire is showing ground (both when the blinker is on and off). I don't want the rear to fail as well.
Expert:  Gm Tech (Cam) replied 1 year ago.

That’s the big question. Because of the unknown load capacity or Ampacity of the BCM rear circuit, and the nature of our issue, its unknown if the rear will handle it, but one thing in our favour is the rear shows a trailer provision so I am thinking with a standard bulb it will work fine.

Customer: replied 1 year ago.
Is there a diagram or schematic for the "trailer provisions?" Also, it shows a left rear and right rear fuse panel. Are those different than the one under the carpet behind the driver seat?
Expert:  Gm Tech (Cam) replied 1 year ago.

There rear fuse blocks are under the second row seat. If you go and look at the first schematic I provided, you will see a branch off each rear for trailer provision.

Customer: replied 1 year ago.
number two pin on brown connector under the dash. Connect and run a new wire from this connection to dark green wire in front right of engine. No need to do anything at the fuse box, correct? Have I missed something?If all that is correct, then: if I upgrade the bulb, I should add my resistor as illustrated in one of your previous images?
Expert:  Gm Tech (Cam) replied 1 year ago.

Yes run that wire to the green wire. No need to go to rear fuse blocks. Yes install resistor as per my diagram when you get it fixed. I don't think you missed anything. However the dark blue white wire in that brown connector pin 5 is the source wire to the front so jump it there and save yourself the wire.