Rear light bulb indicator warning light - gettin' irritated...

[Drake69]

This has started to light up whenever I tap the brakes after starting the car and never goes off until I turn the car off. I removed the rear panels and checked all the bulbs for scoring or carbon, all bulbs are intact. I also checked for loose wiring to each bulb and found one that looked like the screw itself was a little corroded (flippin' moisture... :3d_frown: ). I tightened down all screws but didn't overtorque them and now I get actual illumination when I tap the rear brakes back there (HAH! Fixed a problem I didn't even know I had!!!), BUT I still get the alert light on my instrument panel.

I'm going to remove the spoiler housing next and check the bulb in there (it does light up), but I also noticed the front side marker lights have apparently never come on since I bought the car. I went and got the bulbs for those (haven't had time to pull the assembly off yet), but would those front side markers affect the rear bulbs any? I thought they were on a different circuit.

:1zhelp:

 

[lewis15498]

This has started to light up whenever I tap the brakes after starting the car and never goes off until I turn the car off. I removed the rear panels and checked all the bulbs for scoring or carbon, all bulbs are intact. I also checked for loose wiring to each bulb and found one that looked like the screw itself was a little corroded (flippin' moisture... :3d_frown: ). I tightened down all screws but didn't overtorque them and now I get actual illumination when I tap the rear brakes back there (HAH! Fixed a problem I didn't even know I had!!!), BUT I still get the alert light on my instrument panel.

I'm going to remove the spoiler housing next and check the bulb in there (it does light up), but I also noticed the front side marker lights have apparently never come on since I bought the car. I went and got the bulbs for those (haven't had time to pull the assembly off yet), but would those front side markers affect the rear bulbs any? I thought they were on a different circuit.

:1zhelp:

Its your tail lamp failure box aka "FAILBOX" Its a common problem, you could replace it or just remove it. I did a writeup a while back, I'll post the link, Supracentral also has a writeup in articles.

http://www.supramania.com/forums/showthread.php?t=82576

 

[mecevans]

i have one for sale

 

[Drake69]

Awesome writeup!!! But first I'm going to check the spoiler lights tomorrow and see if they have any carbon scoring, then go through each wire back there and make sure all the connections are tight. I've never soldered before, so if I run across one that's literally hanging by a thread I have a friend that can help. If all else "fails" I'll do the bypass. I'd rather keep the feature and get it to work like it was meant to do instead of throwing it out, but it makes a great stopgap until I find out what the problem really is.

Mucho-appreciated!! +1....

 

[Drake69]

:rant2:Well.... that was semi-fruitless.... :3d_frown:

I found out that the front marker bulbs were touchy, and although I replaced the bulbs with fresh ones, I had to wiggle the blessed things a few times to get them to make contact with the wires, so now both front side markers light up. That's at least a start.

Now, back to the original problem. I got a replacement RLBIWL sensor from a parted out Supra and replaced mine with that, getting the exact same result. The 3rd Light indicator in the spoiler is nice and tight, so THAT'S not the problem, and all the bulbs in the rear come on nice and bright, so THAT doesn't seem to be the issue either. It's remotely possible the new sensor is also bad as well, but I don't think that's very likely, so it's probably a loose wire somewhere in the rear housings (or a loose screw, I didn't get a chance to check all of 'em...). At this rate I may just say what-the-hell and splice out the sensor altogether, but I noticed how tight it is working around back there (especially upside-down when you're looking into the cargo bay...). I could just ignore the S.O.B., but seeing ANY indicator light on my dash is an annoyance to me, so that's gonna last a day or two.

Fun, fun, fun...... :3d_frown::cry::icon_mad::nono:

 

[mecevans]

you need to check the bulb holders. over time the plastic weakens from the heat and the screws come out. use a washer or flip the two eye connectors. took me a couple tries over a couple days to figure it out.

 

[Drake69]

With the help of D7MSupra, I was able to find out what the actual problem was. Someone had mentioned the wiring sensitivity of the bulb housings, and after carefully wiggling the wires on the rear housings the problem went away (this was after I had replaced the sensor and the problem had come right back...). So, apparently if those wires are in any way loose, it can cause that sensor to trigger just like it would if a bulb was going bad.

Thanks to D7M for his help!!!

 

[Victor Charlie]

With the help of D7MSupra, I was able to find out what the actual problem was. Someone had mentioned the wiring sensitivity of the bulb housings, and after carefully wiggling the wires on the rear housings the problem went away (this was after I had replaced the sensor and the problem had come right back...). So, apparently if those wires are in any way loose, it can cause that sensor to trigger just like it would if a bulb was going bad.

Thanks to D7M for his help!!!

If it comes back again, your moisture issue raises another possibility: corroded wiring in the left quarter panel due to water leakage. Water from the hatch or from any openings to the wheel well could also cause this. The water pools in the quarter panels and corrodes the wires. This can cause an intermittent failure. Probably some tail light failure sensors are being tossed needlessly. I hear they can blow like a fuse if shorted, but I had one that just give a false signal due to wiring, and then worked fine in a different vehicle.