Dash light on for rear bulb out, but all lights are OK

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#1
Make
Toyota
Model
Camry
Year
1999
Miles
278,000
Engine
4 cyl
Owner and I and 2 different mechanic have all checked the bulbs and agree all bulbs are working, including 3rd light.

So what triggers the dash light to go on besides a burned out bulb? Could some sensor be the problem?
 
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#2
Some versions have additional bulbs on trunk lid. If both are not working, that can fool you.

There may be a problem with "lamp outage module" behind trunk liner.

Having bulbs of the proper wattage may make a difference.

Viewing bulb brightness (at night) may show up a weak or missing ground circuit.
 
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#3
Thanks. He dos not care about the function of the device, just wants the light to go out on the dash. Can the module be disabled removed or eliminated. If so, how?
 
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#4
Owner and I and 2 different mechanic have all checked the bulbs and agree all bulbs are working, including 3rd light.

So what triggers the dash light to go on besides a burned out bulb? Could some sensor be the problem?
On the bulb side of the Light Failure Sensor find the junction box; I can't recall if it's on the trunk lid behind the tail light assemblies or on the back wall of the trunk - there might be two of them. I no longer have my FSM's to confirm.

Open the junction box and check the screw connections that hold the wires together. Most likely one of those screws is loose.

I owned an '87 Camry that had this same issue. I found a loose ground wire in this junction box. Don't reef on the screws; they're threaded into plastic.

HTH - Paul O.
 
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#5
UPDATE: Both license plate bulbs not lighting. Not sure if they are sensed or not. No one noticed that during previous inspections. One bulb burned out and one OK but neither working . Replaced both bulbs but determined that no 12 volts came to either socket.

Located the Brake Tail Light Failure Module Sensor Relay part # 89373-33180 ($300) in left quarter panel and opened it up but found only a seemingly good looking circuit board. I did not find any junction box to tighten screws like Paul O suggested.

I now suspect a broken wire from opening and closing the trunk for 20 years. Neither the owner or I am interested in tearing into that loom. We tried just eliminating the Module but that left us with no lights.

It now seems like running a 12 volt jumper wire from the tail lights to the lic plate lights would be the simplest solution. It may not turn off the dash light but would allow the lic plate lamps to go on with the tail lights.

Any more ideas??
 

billr

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#6
UPDATE: Both license plate bulbs not lighting. Not sure if they are sensed or not. No one noticed that during previous inspections. One bulb burned out and one OK but neither working . Replaced both bulbs but determined that no 12 volts came to either socket.

Located the Brake Tail Light Failure Module Sensor Relay part # 89373-33180 ($300) in left quarter panel and opened it up but found only a seemingly good looking circuit board. I did not find any junction box to tighten screws like Paul O suggested.

I now suspect a broken wire from opening and closing the trunk for 20 years. Neither the owner or I am interested in tearing into that loom. We tried just eliminating the Module but that left us with no lights.

It now seems like running a 12 volt jumper wire from the tail lights to the lic plate lights would be the simplest solution. It may not turn off the dash light but would allow the lic plate lamps to go on with the tail lights.

Any more ideas??
I'm confused, in reply #3 you indicated the dash light was the main issue:

"...just wants the light to go out on the dash." (be sure to "expand" the quote above"
 
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#7
Hi Bill: But now we need lic lights so cops will be happy. We did not know the lic lights were not working before. More important than an annoying dash light.
 
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#10
:fixed: Well sorta. You gotta love this-- He took an old abandoned very rough road for a short distance and the lic lights came on and the the dash light went off. I just had to let you all know. Seems the bad connection got reconnected.

Saved me (86) and him (89) from any work. It will probably go bad again some day but maybe not before the car or the owner are gone. ;)
 
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#11
Go along with Mobile Dan's post, current sensing is used and if the current is lower than the preset trip point, dash warning lamp comes on.

1988 Toyota is using all bayonet type bulbs then some idiot came out with wedge type bulbs that have constant contact problems. Also some are difficult to read the number on these things to make sure they are the correct type.

Ha, if a turn signal, night bulb, or a brake light is not working, may get shot by a cop in some places.
 

nickb2

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#12
Reviving an old thread. Nickd is right, newer cars use current sensing via the BCM normally.

However, odd as this may sound, and this is a sort of repeat to a response I wrote on another thread, but in line with this new logic boards.

2017ish ram promaster 3/4 series.

3500hd truck.

Low beam on right side out. Apprentice checks it out, ends up in my lap, work order saying no current to right side headlamp MODULE.

High beam also out, plug to headlamp has current all day. Some idiot put the ground in series. Go figure. Lose high beam, loose also low beam and vice versa, don't need to have tesla in your family tree to figure this one out. :cool:
 

nickb2

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#13
Also have to clear bcm code, if not current sensing will just refuse to give power, as it is sensing. So even with two new bulbs, all wiring pristine, BCM won't reset itself without divine intervention of a bi directional scanner.