Why does the bcm have to always come up?

Take a working 3157 bulb out of different socket and try it in that socket. If it works, you have a bad bulb, if not, you have a poor connection, clean and try again, or you may have a bad socket.


Parking light
3157

Front turn signal
3157

Rear turn signal
3157

Tail light
3157

Stop light
3157

Back up light
3157

 

Not 'always'.....only when it's a legitimate failure mode possibility. One of several suggestions being discussed.

 

The bcm controls numerous circuits and yes, that is an easy moneymaker for shady auto repair centers(even if they sell the customer the bcm, they still have to find the problem and fix it)!

Personally I have 30years experience in automotive repair, I've worked @$millions$+++ yearly, volume repair centers the last 20years, and I have never told a customer they needed to replace the bcm. Always found the underlying problem.

 

I did have a bad BCM. I had a rear turn signal/brake light out. I went through all the other things I could think of before replacing the BCM. I wonder if maybe the light switch on the dash is starting to go bad.

 

IF,,,i had the exact same problem, and,IF it were the bcm,i'd wire the front right to the rear right either thru a relay or direct and skip the cost of the bcm.
cant figure why they bothered to have 4 wires from the bcm when there are separate bulbs there anyway,its not like they are switching the brake lites like they used to. ?

oh btw its not the ts switch since the left side,and the right rear are working.

 

If you have the towing pkg. check the wire bundle that goes from your trailer wiring connector. It has been know to rub against the body and cause the insulation to rub off. It is visible on the rear left side. If you open the tailgate it is visible between the bumper and the body. Good luck.

 

Thanks for the further suggestions. For the one that keeps bringing up the bulb I have the correct bulb. I also tried two new bulbs in the socket with same result. For the one who suggested the trailer wiring ill have to check that but it would be wierd that if the wire is rubbing that it would only effect the right turn blinking signal and drl. I'm leaning toward the socket but just don't know. I live in an apartment so had to put it back in for now. When I changed the bulb I went thru the wheel well so for now ill have to wait until I can maybe use a friends garage to go thru the grill a d really look at the wiring. Too bad these seemingly simple things are never easy. You guys are awesome thanks for all the help. Not sure how long it will take me to resolve it but when I do I'll post back and let ya know what in fact it was. Thank you!!

 

trailer wiring is a side issue here as it would affect only the rear and should blow fuses. but you should look at it,as everyone should.

I read here yrs ago that the cure is to push up and forward to unhook it near the rear bumper from underneath. I did mine then and never had a problem.

with the bulb out see if you get any dash warning about a bulb out while you're at it.