Tacoma Towing OEM

If you find a way to get the part number to the connector, I could find a substitute one and you could de-pin it then add a mating set. It be four wires running from there to the bumper. The 2nd Gen has one but that square connector you have seems different. It might be the color.

2nd Gen 4 pin add-on harness

 

If you could fit a cell phone camera to verify the part number.

 

I tried to get in there and get a picture, I may have to wait until tomorrow for daylight to get ones worth sending but the only number I could see on it was J4. But I will look closer with more light and less rain.

 

that would be cool, with this now I wonder with a 4 pin set up and using the trucks harness and fuses what would be the best way to tie in the 7pin? by using a universal 4 to 7 conversion? like this one:
https://www.etrailer.com/Trailer-Wi...dNftqjnCpgPU3TzPxfkwVD5Z7idy9OJxoCGekQAvD_BwE

To clarify, with this I would still have to run 12v from battery and the brake lights to brake controller, as well as the mystery reverse light tap?

 

Looking closer at the connector it seems a match to the 2nd Gen harness connector.

 

Since you have the OEM type already, I'd use that.

 

sure that is my plan but what about the remaining 3 wires from the 7 pin. Also, I got a few more pics to help see if the 2nd gen harness fits.

 

Damn, looks like no part number on it...

 

I'd guesstimate that it is compatible to the 2nd Gen 4 pin towing harness...

90% probable...

 

I like the odds, now the next step would be to get the secondary "engine room" installed. Does said harness go through the firewall to the 2nd engine room?

 

Since it's not there and it has other circuits in it (DRL relay & Inverter relay) I would add a stand alone relay set. One to power the towing break, the other to power the trailer battery charger circuit. For the back-up (reverse) circuit, @daveeasa can sell you a modified harness that taps the rear lamp reverse circuit without cutting the OEM harness.
Or you could assemble it yourself.

 

Thanks caribe makaira for all of the great information. I may end up going with the Takonsha/ Curt Harness, the Reverse Lamp T-one from @daveeasa, then just install the brake controller with fresh wire. cheers y muchas gracias.

 

So I am thinking that I would like to run the 4pin harness you showed me. I have a couple more questions now, 1) once installed and routed what is the part to get from the harness end to the 4pinflat?[edit: oops I didn't look close enough to see it is already included.] 2) I am not going to need the aux "engine room J/B" with the relays because they are for the 7pin system? Can anyone confirm this?

Next in regard to the 7pin setup and all the grounding (only 2 grounds I think) that is happening in the back I am thinking of wiring up a weatherproof bus bar direct to the negative battery terminal so all my grounds in the rear end are directly grounded to the battery and not the body. Any thoughts on this?

 

So I never looked into this one. What is the C/B clutch start for? Manual transmission?

 

Yes

 

Yes, it be easier to set up a pair of weatherproof relays on their own, then acquire the missing relay box and have that wired into the main relay/fuse box.

There is a chassis ground point on the rear driver's side. There even is an extra hole where you could add an additional ground.

 

So you'd only need one weatherproof relay added, and a hot fuse for the towing brake module.
Towing Brake module requires ground, tails, battery fused power, brake input.
T harness for the backup (reverse) lamps.

 

Stop input for Towing Brake Module.

 

@caribe makaira I have found the part number! I sure hope it will fit the gen2 harness!! looks to me like it is saying, part no. 11766
Also, is this harness something you would sell to me? I would be happier to make a sale with you over Amazon.