Bed Light Wiring Advice? (SOLVED)

Hi everyone and Merry Christmas!

I installed my "factory" bed lights and I'm running into a problem - they won't light up! I ran out of daylight so diagnostics will have to wait until next weekend, but here's what I'm finding.

I wired the negative side to this ground:

It's a screw attached to the cluster plug recommended by the instruction manual - which read in step ii on page 7: "...Attach a YELLOW 12-10 AWG T-Tap to the factory ground point (White wire with BLACK trace) on kick panel wall..."

LOL when you take a look at the pic, you can clearly see that they are ALL white wires with black traces, so I just tied in to the screw above since I don't like T-Taps.

I have run the hot wire to the green wire coming from the cab light switch:



Setting the switch to "On" lights up the cab bed lights, but the green wire doesn't register 12v on my VOM even though the factory cab bed lights are on.

QUESTION 1: Is this the correct wire? The searches I have done indicate this is the correct wire to tap into for 12v switched bed lights, but since I'm not reading voltage (and the factory cab lights are lit, eliminating the blown fuse idea) make me wonder if I am barking up the wrong tree. BTW, my VOM was connected directly to the battery (-) terminal on the negative side when probing this green wire. I read another thread where a poster had similar troubles trying to find the correct "green" wire and burned off the insulation on a lot of them with no success.

As a test, I ran the hot wire directly to the battery (+) terminal, my new lights are dead. I'm going to check the wires at the junction in the spare tire well first, then work my way backward, but before I do, here's...

QUESTION 2: Is this the correct ground? I saw a reference in another search that lights may require their own separate ground? The instruction manual is crap and not very helpful.

The irony is that this isn't my first rodeo - I installed these same bed lights in my 2014 and didn't have any issues. Help, anyone?

Cheers!

 

I would use the actual ground strap bolt as the ground not that screw. Not sure what kind of lights these are or what the current draw is but I'd recommend using a relay if it's anything over a few amps. DMM's are good in some situations, but a test light is much easier to back probe multiple wires. Put the ground clamp on the drivers seat rail mounting bolt and then probe the switch with it on. Test all wires with the switch on. Then turn the switch off and retest all those hot wires. Whichever wire is hot with the switch on and ground with the switch off is what you'll want to tap into for either the relay switched power or the lights main power. Also may be a good idea to retest that wire with your DMM to make sure it's a 12V signal and not a 5V signal.

 

According to the Toyota instructions you tapped into the wrong wire.
https://d354nuoz4t18d4.cloudfront.net/b4ebc7b752c2fe024e7feaac4bc89f62/images/custom/install_instructions/00016-34089_TA_16_toyota_mcdonough.pdf

You want the light green wire on a double cab, and purple on access cab. And since the connector you posted is the smaller one (from an access cab), I’m assuming you’ve either got an access cab and picked the wrong wire on right connector, of you’ve got a double cab and picked the right wire color but on the wrong connector.

 

Yep... For both of them. DCSB here. Neither wire in the instructions were apparent to me once confronted by the spaghetti in the kick panel. I couldn't see a plug that looked like the one in the pic, so I went to the switch itself. Bad idea?

Guess I'm an idiot. Any suggestions to find the correct wires?

 

Going by the pics you posted and the ones in the instructions, it looks like You got the wrong connector. You are going into the back of the switch, and Toyota want you to use a connector located where your earth is in the kick panel.

 

By the cargo light diagram, looks like you tapped one of the door switches which are a ground signal. Also looks like to get power you’ll have to find the light green wire in the kick panel as it appears the switch works off grounds to activate the cargo lamp relay.

 

Thanks guys, I'll check again tomorrow!

 

OK, I have located the correct wiring per the "OEM" instructions. No need to pull the OEM cargo light switch or use any fuse box wire taps. Also, since the bed lights are being run off the OEM relay, you aren't in any danger of frying the switch.

After you run the hot and ground wires into the cab, pull them into the drivers side kick panel. The ground wire can be attached to the screw directly above the common negative wiring plug using a ring tongue (no need for a wire tap):

The elusive "green" hot wire that is coming off the relay for the cab lights is located in the white plug nearest the common ground plug (circled in the pic.)

Pull the white plug out and flip it over. The switched wire to the cargo light is center light green(ish) wire in the middle of the bottom row (when plugged in, it is facing the floor of the truck). There is very little clearance here; it's best to cut away some of the electrical tape and use a wire tap once you get clearance. I don't recommend cutting/soldering/splicing this wire since it appears to be 24 gauge and somewhat fragile. The tap shown (included with the installation kit) does the trick just fine; and this is coming from someone that hates taps.

Mount the tap and then plug your positive wire from the bed lights into the tap. At this point you can test your lights, they will run right off the cab light switch as intended! The final installation should look like this:

You can now replace the kick panel and door trim molding. The final result:


So this is it - success! Hopefully someone who has trouble finding the correct wiring due to cryptic instructions will benefit using this guide.

Cheers all!

 

There are factory bed lights?? Tell me more plz!

 

Glad you got this working! I'll be doing this install next week.

Apparently, there are 2 bed light kits. One from South East Toyota 00016-34089 (aftermarket but pretty much OEM quality from what I've read) and the actual OEM bed light kit

$142 PT948-35160

PT948-35160 (double the cost). Don't really know if there is a difference besides price though.

 

I'd love to have wiring diagrams like that install doc.
I bet these don't even draw 200ma total. I'd wire them straight in, no relay.

 

Glad you got it working. I did mine a bit different:

https://www.tacomaworld.com/threads/bed-light-install-w-switch.504421/

 

Thanks for the follow up. I'm wiring up a dome light in my canopy to operate with the cab dome lights. Similar concept to bedlights. If I'm understanding you correctly, there's really no need to pull a ground (-) wire from the bed if I've already got a ground back there; just the (+). That makes much more sense than the factory instructions which suggest tapping into a ground (-) at the plug in the kick panel. I don't understand the necessity of running a ground wire on a negative chassis ground vehicle.

 

Yes, sir. My bed lights are grounded to the sheet metal in the kick panel area. I got the idea by looking at the instructions telling me to tap into a black/white wire that plugs into a common gang that's bolted to metal.

I thought, "why tap the wire? It's all grounded to metal!" It works like a charm.

 

Thank you for this post, saved me a few hours of frustration lol. Bed lights wired up and working fine.

 

Thanks for this. I bought two of these and will be working up soon, so appreciate the correct wiring advice!
https://www.amazon.com/gp/aw/d/B013QLMFA2?psc=1&ref=ppx_pop_mob_b_asin_image

 

Found this thread after effing around for hours with a relay. Thank you for posting this!

 

Thanks again. Courtesy and bed lights are awesome

 

Perfect! Thanks for the assistance!

 

looks good! what underbody lights are those?