"Factory" 7pin Trailer Harness Installation

Interesting, it looks like there was a change made. The 2005 diagram does not show a backup light relay.

 

See the thread I linked need above. It's behind the glove box.

 

I'm glad you edited that, I wasn't sure what exactly you meant. What year is your truck?

 

I have a 2007. And I didn't realize until now that only the later 2nd gens got an extra circuit for trailer backup lights with the relay behind the glove box...

Where's the signal/wire for those backup lights coming from on the 2005-2008?

Makes no sense to me that Toyota would use a towing converter to relieve the trucks own brake/turn/tail light circuitry but not have trailer backup lights governed by the towing converter

 

The converter only "converts" the STOP n TURN circuits. TAIL is not handled by the converter.

 

The back-up light switch in the diagrams.

 

Yes, sorry I meant physically on the truck, where is it?

Edit: the shift lever I guess

 

Switch P1 or B1 are on the transmission itself.

 

I think I got all the wires needed from the junkyard now. Do you have an electrical diagram for the non tow package trucks like the OP's? I'm just curious what Toyota is doing with two different harnesses and what the difference is exactly

The instructions on the Toyota 4pin harness that he bought tell you to plug the 4pin plug somewhere behind the kick panel in a hidden connector.

Pretty sure I can skip that step all together (tho I probably have that connector buried in the kick panel somewhere. I got the towing converter, all the wires, connectors, terminals and relays to retrofit the factory towing package but one of the 4 wires that the OP ran into the cab and plugged into that hidden connector is a ground wire. Why?
Why not just ground it on the frame which is how it is on the tow package equipped trucks or almost all the aftermarket 4pin harnesses

 

Three questions about this:

What's the deal with the E3 junction after the 30A towing tail fuse where the fused wire splits and goes to two different pins on the towing tail relay?
And why does the smaller green-black wire from that relay just terminate after about 30" near or in the firewall?

On the battery charge relay the white-black wire is just a ground wire and the light-green wire I can splice into any ignition positive lead right?

 

It shows that the juice to the relay is split to provide fused power to relay pin 30 (to TAIL circuit of the towing connector) and to pin 86 (+) of the relay. It's tied into the vehicle's tail circuit, which in turn is provided a ground via the BECU. (Body Electronic Control Unit)

 

Why? If the vehicle doesn't have the "package" then it ends there. If it does then ti continues to connector BE1 at rear of vehicle.

 

No it's two wires, both are green-black and that's how it IS on the tow package trucks. The bigger wire goes to BE1 like you say but the smaller one just ends. Look at the schematic you posted

 

Yes, the "only" IGN switched tap in the engine fuse box is the lime green wire on connector EB1, there are other circuits in the cab if you want to go that route.

 

No idea why they have an extra wire split for that circuit....sorry

 

Thanks, yeah from the factory the light green wire actually does run from the battery charge relay thru the firewall into the cab but it ends at some connector. If the other side of it already has the terminal and wire I'll just pop it in there but if not I'll probably splice it right in the engine fuse tray

 

Do you have the diagram of the non tow package trucks for that?

My speculation is that on those trucks the wire doesn't terminate but runs to the 4pin connector (along with signal wires for left turn, right turn and a ground) behind the kickpanel where you plug in the 4pin harness that the OP bought from Toyota

 

It runs into a "hub" that shares the 10 amp IGN N0.2 fuse.

 

Check your INbox...