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A Single Side-Marker Light Not Working (Puzzled, Need Help)

2.9K views 12 replies 4 participants last post by  katekebo  
#1 ·
2014 RAV4 (Limited with Push Button Start, if that makes any difference), its passenger-side front Side-Marker light is not working regardless of all I did below... very puzzled... what/where have I missed?
1. Replaced a new Wedge Bulb, turned light switch to ON - (all lights are lit except for the Passenger-Side front Side-Marker)
2. Wedge Bulb removed from socket, Check Ground with Ignition/Power Off - (tested OK with proper ground)
3. Wedge Bulb removed, turned light switch to ON, voltmeter tested passenger-side front marker light bulb socket - (showing 12.6V)
4. Insert yet another new Wedge Bulb, turned light switch ON - (all other lights are ON except for the Passenger-side front side marker light)
5. Exchanged the Black colored wedge bulb socket with the Driver-side - (all lights are lit except for the passenger-side front side-marker light)
6. Removed the passenger-side front side-marker bulb socket (Black colored) and tested Brown connector for 12V and Ground - (getting 12.6V with light switch turned ON)
7. With the Wedge Bulb Socket disconnected from the Brown/power connector, tested for Short with Wedge Bulb removed - (No short detected despite how i wiggle the contacts)
8. With the Wedge Bulb Socket disconnected from the Brown/power connector, insert the Wedge Bulb in to the bulb socket - (showing connectivity with minimum resistance)
9. Reconnect the Passenger-side front side marker bulb socket with the deemed Good bulb to the Brown/power connector, turned light switch to ON - (tested voltage showing "0" Volt, with all other lights are lit) WHAT WHAT WHAT??? Why is it showing "0" Volt when the bulb is inserted to the socket Yet measuring 12.6V with the bulb removed (I did also tried different wedge bulbs including the working bulb I switched over from the driver-side)

Basically, without the wedge bulb inserted, with light switched to ON the voltage tested Good with 12.6V; however, as soon as I insert the (tried 4~5 different) wedge bulb the voltage dropped "0" Volt... The wedge Bulbs I tried are Good, the bulb socket is also tested Good (remember I had exchanged this socket with the Driver-Side bulb socket), the side-markers on this RAV4 is one of those constant ON type (Not that alternates with the Turn signal) so I don't think there is a relay to deal with (or is there ?)... Since all lights are lit (except for this passenger-side front side-marker light), I don't believe there is a bad fuse either ... I am simply puzzled at this point... can this be some kind of control module issue, yet, it is only this single Passenger-side front side-marker that is not working.... Can anyone help/thoughts?

Thanks!!
 
#3 ·
Thanks for the reply!
Yes, I did also tried the driver's side bulb on the passenger side (both using the socket from the driver's side and the socket originally on the passenger sids)..
P.S. I did also bench tested all the wedge bulbs I tried using a 110V to 12V converter to be sure all the bulbs are good.
 
#4 ·
Very strange. I believe the circuit is quite simple. There's a single taillight relay and fuse that supplies power to the tails and marker lights. The relay is under control of the body ECU. The only possibility I can think of is a very resistance somewhere in the wiring to the marker light such that you get 12V under no load (i.e. measured with a multimeter), but zero as soon as you pull some current through it. Have a look at this schematic Maybe check the wiring from the A70 connector out to your marker light.
Image
 
#5 ·
Fantastic! That ("... a very resistance somewhere in the wiring to the marker light such that you get 12V under no load (i.e. measured with a multimeter), but zero as soon as you pull some current through it. ") would definitely explains what I have encountered (multimeter read 0 Volt indeed), I will take a look then report back ASAP (my wife has the RAV4 and is currently out of down, so may be after the Christmas before I can get my hands on the wiring).
For now, Thank you for the insight and very helpful diagram!
 
#8 · (Edited)
.... I will take a look then report back ASAP (my wife has the RAV4 and is currently out of down, so may be after the Christmas before I can get my hands on the wiring).
....
Unfortunately, my capability and tools (basically my my multi-meter) are limited, I was only able to track to the relay (by swapped relays of the same from other locations) & fuses (for continuities) panels and still cannot isolate down to which/where the component that causes a single passenger front-side-marker to not working properly (showing 12V without the bulb installed, yet drops to 0V with the bulb installed... 😵).

Even with the diagrams from grampas_sienna (Thanks again!!), I was not sure where the two components (circled in RED in the attached picture below) are physically located (perhaps I had touched it/them when checking the relay/ fuse block while looking behind the passenger side kick panel or behind the lower dash cover under the steering column somewhere.. , lacking the knowledge what they look like...)

Hmm... I will keep trying if I can think of other ways to go about diagnosing ...
 

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#10 ·
Just wanted to close this discussion and Sincere Thanks to grampas_sienna for the help and information, Thank You!

This RAV4 received a Battery Recall notice a week+ ago, I was scheduled for a Pre-Recall Service inspection this morning (01/02/2024)... the dealership service advisor noticed the non-working side-marker so I asked them to look in to it... after an hour of diagnoses and $120, I was told they will need another minimum 3-hours ($599) of wire tracing to "possibly" determine the issue :oops:. I guess I will just give-up until I can think of something else to try from here. Thanks!
 
#11 ·
As @grampas_sienna said, when a socket's positive cable/terminal shows +12V without the bulb (no load condition) and 0V with the bulb in (under load), it means that there is high resistance (a loose / corroded connection) somewhere along the positive cable path. A digital multimeter has an input impedance of many megaohms, it practically puts no load on the circuit and even a corroded / loose connection will supply enough current to get a good measurement. I think your only choice is to trace the cable back all the way from the socket to the fuse/relay box and look for any loose/dirty connection. Alternatively, you could just pull a new cable from the fuse/relay box to the socket, if you are handy with electric wiring.
 
#12 · (Edited)
.... A digital multimeter has an input impedance of many megaohms, it practically puts no load on the circuit and even a corroded / loose connection will supply enough current to get a good measurement...
katekebo , I appreciate what you have said, that is so right and I had simply overlooked that, Thank You!

Being a lazy individual that I am with a bad-back, it scares me :oops: having to trace the wires and unwrap all those nicely factory wrapped wire bundles/looms, so I figured, Corrosion = Resistance as Current flows through that corroded section should generate extra heat (not by much, but will be slightly higher temperature than the rest, so I used my handheld Infrared Thermal Scope followed the wires from the side-marker bulb socket down and under then around the windshield Cowl/Firewall ... I was unbelievably fortunate to locate only one section of the wires (about 1.5" long, still nicely wrapped within the OEM wire loom just below the headlight assembly) showing a mildly higher temp color on the scope... to make an already long story short, I cut-out then re-soldered/connected the wires (then relocate how the wires/looms are routed/arched) and the side-marker is now working again. I suspect the corrosion was from years of soaking in car wash detergent as the detergent has an unique aroma (approximately 1/3 oz of liquid dripped out of the wire loom when I pried it open ---- my wife takes her RAV4 to a local Delta Sonic Car Wash every couple of weeks)...

A Big Thank You to all of you guys for the help, information and quick responses !!! Sincerely, Rick
 
#13 ·
90% chance that the high resistance spot is in a connector, not along the wire. It can be dirty, corroded, loose or damaged. Start with the connector to the offending light. Disconnect, inspect, clean, put some dielectric lubricant, reconnect. Follow the harness until the next connector. Repeat. All it take is just one "pin" to be dirty, corroded, loose or damaged to cause the problem. The rest of the connector can be perfectly fine (actually, it is as the rest of the lights are working fine).