Wiring 2008 4R SR5 V6 for trailer brakes

[xxaarraa]

Hey guys, I'm about to buy a dual axle 7x12 trailer and want to wire my 4th gen for trailer brakes.

Mine is a V6 and only has the 4 pin connector in the back. I know I need a brake controller that I need to plug into the empty plug underneath the steering wheel area, and my search reveals that the 'tekonsha' unit works well.

What I haven't been able to find an answer to is what wiring needs to be done in the back? I am assuming you need something more than the regular 4 pin flat on the rear bumper side, correct?

Inputs and recommendations for model numbers of any units to get would be much appreciated. Thanks all.



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[RonJR]

Yes, you'll need a 6 or 7 pin connector to have the extra line for brakes. I'd go with the 7 pin - that's kind of the standard nowadays and it's likely your new trailer will already be wired with that.

You can buy the 7-pin sockets with mounting bracket at any auto parts stores, and they'll have the standard wiring diagram shown on the packaging somewhere. All you'll need to do is transfer the turn signal and taillight wires from your 4-pin, run a wire back from the brake controller, and mount it to suit yourself.

 

[xxaarraa]

Yes, you'll need a 6 or 7 pin connector to have the extra line for brakes. I'd go with the 7 pin - that's kind of the standard nowadays and it's likely your new trailer will already be wired with that.

You can buy the 7-pin sockets with mounting bracket at any auto parts stores, and they'll have the standard wiring diagram shown on the packaging somewhere. All you'll need to do is transfer the turn signal and taillight wires from your 4-pin, run a wire back from the brake controller, and mount it to suit yourself.

I see. Thank you.

 

[xxaarraa]

Thanks for your thoughts guys. I wired in the prodigy p3, very easy job. Dialed it in when I hooked up the trailer for the first time by following the instructions that came with it. I also added a Bluetooth obdII module to keep an eye on my transmission temps via my smartphone. So far everything's gone smoothly.

 

[alia176]

Just for my knowledge base, do the V6 Runners have a trailer wire harness already under the dash, ready to accept a E-brake controller? My V8 has one so I was simply curious.

What app are you using, Torque Pro?

 

[xxaarraa]

Just for my knowledge base, do the V6 Runners have a trailer wire harness already under the dash, ready to accept a E-brake controller? My V8 has one so I was simply curious.

What app are you using, Torque Pro?

Yup. If you have the tow package, even the v6 has the unused pin under the dash and 7 pin connector in the back - it's pre wired for trailer brakes.

Yes, Torque Pro. Had to create two custom PIDs to monitor trans temps but easy to do so. One is temp t the tranny and one is temp f trans fluid at radiator.

 

[TechWrench]

Yup. If you have the tow package, even the v6 has the unused pin under the dash and 7 pin connector in the back - it's pre wired for trailer brakes.

Yes, Torque Pro. Had to create two custom PIDs to monitor trans temps but easy to do so. One is temp t the tranny and one is temp f trans fluid at radiator.

I am curious about the source for the trans temp #2 reading. You indicate it is the trans fluid temp at the radiator. I wasn't aware there was s second sensor monitoring the trans fluid at the radiator. I only knew about the one on the transmission.

 

[xxaarraa]

I am curious about the source for the trans temp #2 reading. You indicate it is the trans fluid temp at the radiator. I wasn't aware there was s second sensor monitoring the trans fluid at the radiator. I only knew about the one on the transmission.

See my post here: http://www.toyota-4runner.org/showthread.php?t=225475

 

[TechWrench]

See my post here: Towing with a 4th gen V6. Brake controller, what else? - Toyota 4Runner Forum - Largest 4Runner Forum

I remember that thread, and re-read it again, but all I can see from your posts is that you are using an app to read info from the OBDII port. That doesn't give me the answer I am looking for, which is, what is the source for the 2nd trans temp reading? I will have to look further into this.

 

[xxaarraa]

I remember that thread, and re-read it again, but all I can see from your posts is that you are using an app to read info from the OBDII port. That doesn't give me the answer I am looking for, which is, what is the source for the 2nd trans temp reading? I will have to look further into this.

It's explained in the screenshot I posted. That user explains it clearly.

Reposting it here.

 

[TechWrench]

It's explained in the screenshot I posted. That user explains it clearly.

Reposting it here.

View attachment 221937

Ok, I read that, and went through the associated threads linked in the thread.

Not trying to be difficult, but I am having some doubts as to what the 2nd trans temp reading actually is. I have an '03, and the newer units ('06 and up) may be different, but according to my understanding, and the electrical wiring diagrams (specifically page 239 in the Pub. # EWD514U which I have) it shows two temp sensors imputing to the engine control module, A3 - A/T Fluid Temp. Sensor (Input signal THOC), and E2 - Engine Coolant Temp. Sensor (Input Signal THW). I admit, this diagram is for the 1GR-FE V6 variant, but interestingly, the diagrams for the 2UZ-FE don't appear to show any sensor for A/T temp, only the E2 - Engine Coolant Temp. Sensor, which also inputs signal THW to the Engine Control Module. In any case, I am suspecting that the reading for Trans Temp 2, that the app is monitoring is actually the Anti-Freeze/Coolant in the radiator, and not actually the trans fluid temp from the internal trans fluid cooling loop inside the radiator.

I suspect that, depending on how fast the fluid is passing through the cooling loop, and the its temp as it enters the loop, the trans fluid temp exiting the radiator may be close to the actual cooling temp. But, if the incoming fluid temp is too high, the internal cooling loop may not be adequate enough to lower the fluid temp to the optimal level, which would explain the need for an aux cooler added to the fluid circuit after the radiator cooler.

An interesting conversation, and one I plan to investigate further.

Thanks for your patience.

 

[xxaarraa]

Ok, I read that, and went through the associated threads linked in the thread.

Not trying to be difficult, but I am having some doubts as to what the 2nd trans temp reading actually is. I have an '03, and the newer units ('06 and up) may be different, but according to my understanding, and the electrical wiring diagrams (specifically page 239 in the Pub. # EWD514U which I have) it shows two temp sensors imputing to the engine control module, A3 - A/T Fluid Temp. Sensor (Input signal THOC), and E2 - Engine Coolant Temp. Sensor (Input Signal THW). I admit, this diagram is for the 1GR-FE V6 variant, but interestingly, the diagrams for the 2UZ-FE don't appear to show any sensor for A/T temp, only the E2 - Engine Coolant Temp. Sensor, which also inputs signal THW to the Engine Control Module. In any case, I am suspecting that the reading for Trans Temp 2, that the app is monitoring is actually the Anti-Freeze/Coolant in the radiator, and not actually the trans fluid temp from the internal trans fluid cooling loop inside the radiator.

I suspect that, depending on how fast the fluid is passing through the cooling loop, and the its temp as it enters the loop, the trans fluid temp exiting the radiator may be close to the actual cooling temp. But, if the incoming fluid temp is too high, the internal cooling loop may not be adequate enough to lower the fluid temp to the optimal level, which would explain the need for an aux cooler added to the fluid circuit after the radiator cooler.

An interesting conversation, and one I plan to investigate further.

Thanks for your patience.

Not sure what your confusion is. It says very clearly that those PIDs are for the 750 tranny. If you have an older tranny you need to research itfor your specific tranny.

I'm not saying that what that user posted is absolutely accurate. I just don't see a reason why it won't be, he seems to know what he's talking about and I'm pulling two different temps like he said.

If you look closely, he's using the same PID but the equation / calculation down below is different for the two different temps. I take that to assume its possible to approximate the temp at different points in the cooling system using different math. I just assume the whole thing is a reasonable approximation and not 100% and for my use, I'm ok with that.