Turn Signal Mirror Lights

M4X

Tremor Fanatic
Joined
Mar 28, 2021
Messages
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Location
Texas
Current Ride
'22 Plat Tremor 6.7
Current Ride #2
'22 Rivian R1T
Simple problem, maybe not so simple solution.

My truck did not come with turn signal mirrors even though it has the $1,075 Power Equipment Group option. I inspected the 22 pin connectors and confirmed that they are wired for the turn signals, the clearance lights, the power functions, the heat, and even BLIS even though my truck does not have the appropriate tail lights or modules for that.

So I bought a set of aftermarket lights knowing full well that all of the "features" wouldn't work for about $380 vs spending nearly $1.5k on some OEM mirrors. Specifically got these: https://www.americantrucks.com/supe...s-smoked-turn-signals-rmx-f25017f1h-p-fs.html

The only features my truck does not have that these mirrors do is BLIS.

So I plugged them in and everything works except the turn signal. (Power is fine, heat is fine afaik, and the clearance lights even work.)

signal-2021-04-19-145420_001.jpeg
signal-2021-04-19-145420_002.jpeg



The only problem I have is the turn signals will not activate.

I can't seem to find access to any wiring diagrams for the truck (or any 2020+ for that matter) online, but what I found for other years (2017+) is that Pin #7 on the driverside is supposedly the Turn Signal Positive.

So I put a multimeter to it, found a good ground, verified voltage on other pins, then turned on the truck and turn signals/hazards. 0 volts to Pin #7 even though it's wired. Either I'm checking the wrong pin, don't understand how the signals work due to lack of electronics knowledge, or there is a missing link somewhere else in the truck.

Any advice?
 
Last edited:
Yes, I changed alot of things on day 2 of having the truck. Just download their most recent update

I'm sure there is probably a thread on this anyways.... But could you recommend an OBDII dongle for forscan?
 
I'm sure there is probably a thread on this anyways.... But could you recommend an OBDII dongle for forscan?
This is what Forscan recommends for Forscan lite. They recommend a wired connection but this works fine for me.
 

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How do you go about getting forscan for a 21? Does it come with a laptop typically or do you need to buy a laptop and download it?
You can use Forscan with a smart phone or a windows laptop. The laptop is the easiest way. You need to be able to open spreadsheets and read them well, kind of hard to do with a small phone screen. Make sure you get a laptop with Bluetooth connectivity so you can use a wireless OBD II device like the one in the previous entry. Watch some Youtube videos on the process. It's actually pretty easy. There are threads on the Forum about the topic and some have shared the needed spreadsheets. Spreadsheets can also be found using a Google search.
 
You can use Forscan with a smart phone or a windows laptop. The laptop is the easiest way. You need to be able to open spreadsheets and read them well, kind of hard to do with a small phone screen. Make sure you get a laptop with Bluetooth connectivity so you can use a wireless OBD II device like the one in the previous entry. Watch some Youtube videos on the process. It's actually pretty easy. There are threads on the Forum about the topic and some have shared the needed spreadsheets. Spreadsheets can also be found using a Google search.
Thanks for all the info
 
How do you go about getting forscan for a 21? Does it come with a laptop typically or do you need to buy a laptop and download it?
Also don't be tempted to save a few bucks and get one of the cheap no name OBD II links. There's a lot of information on line about problems folks have had using the knock offs. Forescan recommend certain ones for a reason. Go to the Forescan site and read what they have to say and watch their videos.
 
Hmm...

Looking at the 2020+ Forscan Spreadsheet does not show anything about enabling turn signals on the mirrors.

I'm guessing that is part of something I've read about called the "as built" data?

Is there more functionality to forscan than what is on this spreadsheet?

If not, then maybe it cannot help me here.
 
Hmm...

Looking at the 2020+ Forscan Spreadsheet does not show anything about enabling turn signals on the mirrors.

I'm guessing that is part of something I've read about called the "as built" data?

Is there more functionality to forscan than what is on this spreadsheet?

If not, then maybe it cannot help me here.
Within Forscan you can go to specific modules (I.E. the BCM) and turn options on/off. You don't have to do everything by the spread sheet but you have no choice on some options.
 
Hmm...

Looking at the 2020+ Forscan Spreadsheet does not show anything about enabling turn signals on the mirrors.

I'm guessing that is part of something I've read about called the "as built" data?

Is there more functionality to forscan than what is on this spreadsheet?

If not, then maybe it cannot help me here.
I hooked up to a 2021 STX yesterday and I did see the option to activate mirror turn signals, power fold, and the puddle lights under the BCM section.
 
Yep that was it. I just had to enable the turn signal under the DDM/PDM's in Forscan.

 
I had try looked into both DDM and PDM modules but did not see any selections for mirrors or turn signals options at all. May be the 22MY they leave them out.
 
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