Right Turn Signal

[dpm6836]

Just moved over from that other site.

my 02 TB is at 152K. Just replaced the tccm and got the 4wd working again.
Only other problem is the right turn signal. when it is cold (I live in PA so it is 20-40 degrees now), it will not operate. If the TB warms up and I play with the swtich it will then operate. I changed the swtich yesterday with one bought from rock auto. it still does the same thing. I changed the rear bulb, no luck.
I don't get the fast flashing or anything, the turn signal is just dead when it won't work. Could he be the flasher module? Wiring problem?
Thanks in advance!

 

[Trailshaman]

check the plug going into circut board and the one the bulb is pluged into. i have had a bit of trouble with mine in the past. i assume you are talkin about the rear lights correct?

 

[The_Roadie]

If neither the front nor the rear lamps flash, then it's not the lamps or the circuit board. I've read more reports about rare simultaneous failures of headlights than turn signal lamps. The turn signals just get so much less use.

Sorry you didn't ask here before buying a new switch, but statistically, it's about ten bad flasher modules to every bad multifunction switch. It's located on the firewall above the driver's feet. TO get help locating it if you need to, turn on the working turn signal and listen for the clicking. It could also be slight oxidation on the wiring connector to the flasher module, so try unplugging and replugging it 3-4 times before buying a new flasher module.

I hope that works, and you can come back to report a no-cost fix.

 

[dpm6836]

Yes, neither front or rear right side works. I will try the unplugging and replugging.
And yes, I should have talked to you guys before putting in a new switch. I know my wife hit the swtich hard one time so I assumed it was damaged. Especially to the right side so I took a chance. Live and Learn!

 

[dpm6836]

It was the lighting control module. I needed a new one which I got from Rock Auto. It is installed and working. Thanks for help.

 

[jccrall]

I know this is an old thread but I have the same problem. I wonder just what the lighting control module is?? Are we talking about the flasher??
Thanks

 

[The_Roadie]

Another (less precise) name for the flasher. Yes.

 

[jccrall]

Ah ha. Thanks Roadie,

Now I'm wondering if I have the right part# for the unit. The one I have is GM 12450284. It is labeled 2/4-W/OPT Trailering and I do have the trailer package on my Trailblazer.

 

[The_Roadie]

That's the right part number. For once, it's not a unique part to our platform, and they're widely available for a decent price in the usual spots including local parts stores.

 

[jccrall]

That's the right part number. For once, it's not a unique part to our platform, and they're widely available for a decent price in the usual spots including local parts stores.

Humm Roadie,

I figured out a way to pull the module without breaking my back (I'm 79 and getting a bit stiff for this stuff) because I wanted to make sure that it did not have a bad (corroded) contact pins. The pins all look fine.

Low and behold the module number is quite different from the one I came up with on the WEB. Instead of GM 12450284 the module in my 2007 Trailblazer is GM 15231201 (go figure). I don't know if the GM 12450284 would work in my SUV or if someone substituted the GM 15231201 for the original (I bought the TB used with 22000 miles on it).

Are you sure that the GM 12450284 is the correct module for a 2007 TB LS???

Thanks,

John

 

[jccrall]

Well OK,

I roughed up the pins on the module and sprayed a bunch of CRC QD Electronic Contact cleaner in the plug holes. When I plugged the module back in the turn signal is now working. I am hoping that it was just a bad connection (and thus saves me a bunch of money LOL).

Time will tell but for now I seem to be good to go!!!!

Oh yes a little research revealed that the GM 15231201 is an updated replacement for the GM 12450284 (which probably would work OK in my 2007 TB).

Thanks to all,

John

 

[jccrall]

Well so much for clean and reinsert the module. I took a drive and the signals worked for about five turns and then quit. Guess I am in the market for a flasher module. Hope that will cure the problem.

John

 

[Sparky]

Ah bummer. I hate it when it starts to work, gets your hopes up, then goes "NOPE!" and quits again.

Although here's another crazy idea - maybe it is a bad solder joint inside the module? I've repaired BCMs, blower motor controls, and several other things from various cars by simply resoldering a bad connection.

 

[jccrall]

Ah bummer. I hate it when it starts to work, gets your hopes up, then goes "NOPE!" and quits again.

Although here's another crazy idea - maybe it is a bad solder joint inside the module? I've repaired BCMs, blower motor controls, and several other things from various cars by simply resoldering a bad connection.

Hey it may be something simple like a solder joint and I may tear into the module and see what it is made of!!

In the meantime, I just decided to bite the bullet and get a new module. I found one on Amazon for $28 and change with free shipping so I ordered it. It came in a couple of days and seems to have fixed the problem. I have done a lot of signaling without a single failure!!! I use my turn signals every single turn or lane switch so I felt that it was essential to get it fixed.

Hope this thread helps others with bad turn signal modules.

John

 

[LikeEnvoy]

Inside the flasher module:......

I had no left turn; only the right worked.
Left made two click sounds (no lamps) and stopped.
I tried opening the flasher and tracing out the circuit. I ended up with a reasonable schematic of the circuit and traced the problem to one of two relays which are used to select left or right lamps.
The relays are sealed but I unsoldered the bad one and removed it from the PCB. I prised it open and examined it.
The moving arm inside has two isolated sets of contacts. When it energises it should join both of these contacts to the common arm.
One side of the contacts had a smaller range of movement than the other, so when it hit either end, the other contact did NOT contact: no lamp power output.

I was able to finely adjust the contacts so that both made contact and now it works!


HOWEVER.... for all of you out there- it's not worth the bother!
In future if it goes bad again I will simply replace the module and I advise you to do the same.

It was satisfying to find the problem and fix it but it took a few hours of peering through a high power magnifier and drawing the circuit.
I think I have seen the part on sale for about $28, as John said. Mind you that's US$ and in Canada it's probably a fair amount more!
Even so, for most people it's not a practical job, so change it.

 

[LikeEnvoy]

..Update.. the flasher again stopped working on left turns (Fall 2015) so ordered a new one. The best price I found turned out to be one digit different in part number and it flashed much too quickly. Swapped the metal strip component inside for the old one and it now has correct timing.