Alright I need the masses to steer me in the right direction. Car is an 03 Matrix XRS & in the month I've owned it I've noticed the low beam failure indicator light come on every now & then when there is no bulb out. When this light comes on the backlight on the stereo goes dim, light goes off the backlight reverts back to it's default setting. At first I thought it was related to the factory Nav unit since that had CD read issues when it felt like it. Since replacing the headunit with a Pioneer Double DIN unit it does the same thing. I am not sure how the two are related but somehow they are. What should I be looking at to try & fix this?
Hal
SuperDork
4/1/15 3:22 p.m.
MA$$hole wrote: What should I be looking at to try & fix this?
Step 1: Check every ground connection you can find.
On mine, has day running lights, as soon as it's dark, head lights brighten, inside lights dim so it's less distraction.
This has the DRLs as well, but it doesn't matter if it's bright or dark at the time. It's not like it's an issue that needs to be fixed, just odd.
Hal wrote:
MA$$hole wrote: What should I be looking at to try & fix this?
Step 1: Check every ground connection you can find.
Yep. Wouldn't doubt it if the headlight was losing its ground at the headlight assembly, and finding a new ground through the parking light circuit via a shared ground.
Shared grounds are nice until that ground point goes away, then whatever you were grounding find a new ground in series with whatever it was sharing with, instead of in parallel. A headlight will not draw much current if it is grounding through another bulb. and I'm pretty sure the Toyota bulb-checking modules actually monitor current.
Of course, I also remember the Camries of maybe 15-20 years ago where the prime cause of bulbs inop was the trunk-mounted bulb check module burning out PC board traces...
