Cargo Area Liftgate Lights not Working

skybum02

skybum02

New member
My cargo area liftgate lights stopped working mysteriously.

Does anyone know what fuse they are on? I looked and din't see one blown...but I may have missed it.

What else besides two burned out bulbs would cause them to stop working.

Thanks.
 
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skybum02 said:
My cargo area liftgate lights stopped working mysteriously.

Does anyone know what fuse they are on? I looked and din't see one blown...but I may have missed it.

What else besides two burned out bulbs would cause them to stop working.

Thanks.
Click to expand...

Is the switchs turned on to door or on?
 
skybum02 said:
"...What else besides two burned out bulbs would cause them to stop working."
Click to expand...

Hi sky,

The rear "Tailgate Spotlights" are connected to the "Multiplex network door ECU", located in the lower center tailgate. They are fed by the interior courtesy lighting circuit fuse. Check to be sure the Spotlight ON/OFF switches are in the 'intermittent' position. Rgds
 
skybum02 said:
It is just those that are not working...strange.
Click to expand...

I never heard you say that you checked both bulbs and they each checked out OKAY! If you haven't, they need to be checked before going any further. After this you'll need to verify power (and ground) at the tailgate bulb sockets and then harness connections at the 'Multiplex network ECU'.
 
rigtec said:
I never heard you say that you checked both bulbs and they each checked out OKAY! If you haven't, they need to be checked before going any further. After this you'll need to verify power (and ground) at the tailgate bulb sockets and then harness connections at the 'Multiplex network ECU'.
Click to expand...

The bulbs look good...I'm going to get my multimeter now. Where is the Multiplex network ECU located?

Thanks.
 
skybum02 said:
The bulbs look good...I'm going to get my multimeter now. Where is the Multiplex network ECU located?

Thanks.
Click to expand...
Here:

rigtec said:
Hi sky,

The rear "Tailgate Spotlights" are connected to the "Multiplex network door ECU", located in the lower center tailgate. They are fed by the interior courtesy lighting circuit fuse. Check to be sure the Spotlight ON/OFF switches are in the 'intermittent' position. Rgds
Click to expand...
 
skybum02 said:
"The bulbs look good...I'm going to get my multimeter now..."
Thanks.
Click to expand...

You'll need to verify that you have both 12V POS and GND! Just don't forget that this vehicle features 'ground-side switching circuitry'; which means that the loads e.g., bulbs, motors, electric heaters... are ALWAYS HOT, straight from the "ACC/IGN" circ. fuses. Now, using your meter you'll need to check the circuit for power at the "Tailgate Spotlight lamps". Find a good ground point for the NEG meter probe (near-by screw or bolt head) and test for 12V at the bulb contact making sure that the light switch is in the OFF position.

If you've established that you do have 12V at the lamp socket, connect your POS meter probe to that 12V power supply (RED wire) and check for ground NEG at the BLUE wire (Intrmt) ON/OFF: color applies to both the left and right side spotlights (constant ON GND wire is VIO on left, WH on rightside).

PS: I'll try to locate this wiring diag which I may already have posted online (somewhere?) and post it here on Monday. If I don't find it, I'll have to scan it to my computer, then to photobucket, and then send it here as a photo; these Mitchell diagrams are printable, but 'non-transferable', which means they cannot be shared electronically e.g., emailed, copy/pasted...etc. Rgds!
 
To team members who may find these "5th gen 4Runner" schematic diagrams helpful:

These are the 'Courtesy Lamp circuit' wiring diagrams; please see print 2 of 2. For the purpose of the OP I have the 'Tailgate Spotlight' components marked, traced, and labeled for convenience. Now just because the vehicle shows No power at the tailgate overhead lamp sockets/bulbs, it doesn't mean that there is no 12V power source at that location. It could however, reveal that there is no 'Earth Ground' provision for current to flow as well; which is much more common these days where the "Switched Ground" circuitry method is so often used... "See below":


At the lower RH corner of the above diagram, the Right and Left hand spotlight assemblies are traced in blue and all of the light switch wiring is labeled, as well as the 'Multiplex Network ECU' system wiring.


If you follow (pink trace) the 12V power supply line (RED wire) which connects to the B1 terminal at the multi-plx Ntwk, you'll be able to see how it relates to the entire courtesy lighting circuit/driver-side fusebox. skybum02: Try to find out if you lost the 12V power supply, or the "Switching" 'Earth GND'... Hope you'll find this helpful(!) ...and please let us know how you made out,

rigtec, Cheers
 
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rigtec said:
rigtec, Cheers
Click to expand...

OT: Hey Rigtec - Did you ever get your HO alternator issue figured out? I'm extremely curious if it was the cause of your gremlins, and if not what was to blame. I prodded for updates in the original thread a while back (twice I believe?), but I guess you stopped following it...

Thanks for any follow-up :)

Back OT :cool:
 
Randyman... said:
Sweet! So the HO Alt is still cranking away then? Good to know the HO option is viable "just in case" I get a hair up my butt :) Thanks for the update!!!
Click to expand...

There are a lot of guys with newer (late model) vehicles that are using both 'High Output' Alternators, as well as 'Multi-mode, Dual Battery set-ups' and no issues regarding the 'Multi-plex Network' power management ECUs'... these 'OBD-ll' networks have been operating since about 1996, and are highly reliable! Rgds
 
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