Installing the Factory TSB A/C Condenser Fan (DIY)

BAM in my experience, like Toyota Parts Deal, cancels orders when parts are back ordered. I think you’ll have better luck at Sparks or any other real dealer. But I dunno.

For the wiring, I’m not sure I understand. The TSB I look at shows going to pin 16, connector 1F. Where are you seeing it says to use pin 32?

For my truck, I had to keep the wire I spliced into intact because it fed other circuits, I think the clutch start circuit and some other stuff. I don’t recall but I know I looked into it and the wire I spliced into, I definitely had to keep intact.

I do vaguely recall deviating from the TSB but now that I look at the TSB, I can’t see why or what I would have deviated from.

 

Is there a part number for the TSB wiring harness? I suck at automotive wiring.

 

Sorry, that was a typo. Pin 16, not 32. In your write-up, it looked like you left the original wire and your new wire connected. In TSB, they leave the original wire disconnected.

82112–04050 wire, engine room no. 2. It’s listed in the TSB. Not trying to be a dick, but if you suck at wiring, you may want to ask a friend for help. Even with the harness, there’s still splicing and adding a pin into a crowded connector.

 

Wow how have I not seen this upgrade yet, will absolutely be adding this to my 21. Summer is pretty brutal so far and I was just noticing this behavior.

 

I just went through the diagram again and reminded myself of why. On every part of the diagram where 1F pin 16 is mentioned, it is referred to as (M/T), so it must be a manual only thing. According to the diagram it only feeds the cruise control clutch switch (top of the pedal, disables cruise with pedal press), and so it's definitely necessary on mine. It is just a simple 7.5A ignition circuit.

No idea why they would tell you to snip the wire and tape it off if the wire is there, this TSB must officially be for automatic transmissions only or something. Between that and the relay box that needs to go where the clutch reservoir goes, a technician that goes strictly by the book would be dumbfounded trying to install this on most MTs.

So I guess they assume all trucks getting this TSB are automatic, and if the wire is there, great, still not needed, but if it's not there, then you insert the pin. For me it was there AND needed, so I spliced into it.

Bottom line, if the wire is there already, then it can't possibly hurt to keep it spliced together, and if you have an automatic then snipping it and folding over the unused end will work fine too.

Edit: Looks like the TSB is indeed only officially supported for automatic transmissions and the V6. So that is why the instructions would say what they say.

 

I wish it was a bit larger/stronger of a fan, and sat a bit closer to the condenser to ensure pushing the extra airflow directly into the condenser, but I'm happy with it. Honestly, it doesn't come on that often, but so far 2025 and definitely 2024 were some of our more mild summers, with a lot less days over 100 than usual. It seems to come on when parked at idle on 95ish days for the most part, but it's not 100% consistent, so it's hard to say exactly when it comes on. At 100 and above, I would say it's on pretty much anytime parked.

Brief testing shows it to shut off once you're moving faster than 10 mph or so...but I didn't test that for very long. A light on the dash tied in would be neat to see from the driver's seat when it's on, to figure out the pattern.

 

It was 118F on Wednesday so this would absolutely be a nice addition. And yeah, as soon as I start moving it is instantly cooler (as I'm sure you noticed without the fan). Only really makes a difference on days that are over 105 or so, but that is all of them the last few summers. I'm sure adding some additional ducting wouldn't be too bad to do if it doesn't help enough.

 

Yeah, at 118 I imagine it will be on anytime you're stopped, maybe even sometimes when moving at low speeds. Overall it's intelligent and knows when to turn it on, which was why I hooked it up to follow stock operation. It boggles my mind that they put in the effort to install a fan on the Mexico-spec trucks, but not anyone in US or above. It's not like it doesn't get hot here, but still gets hot in Mexico. Penny pinching I guess. Not many Mexico spec trucks, so I guess install fans on the minority of trucks that make it into that destination.

 

I can give one data point. 95 out currently, truck is parked in the sun idling after driving 27 miles home. AC is on auto, set to LO, fan is running consistently (for several minutes now). Air out of the vents is nice and cold. My infrared says it’s maintaining 25-30°F. Not sure how accurate that is, seems low. But then when I hold it on the hood, it’s 140°F, which seems right.

Seems like when it’s warm out and you want max cooling (aka LO on auto), it does everything it can to get there including running the fan for as long as the compressor is on.

Edit: condenser fan has ran for over 10 minutes steady in the same condition. So ask more of your AC, you get the fan!

 

Thanks. I may tackle it this fall, when it is cooler outside. I have a 10yr/100K warranty on the truck, so I could try to have a dealer do the TSB, but I have not been impressed by 2 local (30 and 50 miles away) dealers. I think I can do better than them, if I take my time. I can run house wiring, but last automotive wiring I did was 25 years ago.

 

for $750, I think you might be better off with the PEM electric fan conversion, and Lingenfleter control, delete the manual fan, and then use the TSB to add an intelligent relay control for raising the fan speed when the free air is not adequate, for engine or AC. Very happy with this setup, and the TSB relay control certainly solved my AC problem when moving slow or at cold engine start with very slow movement before getting to an open road. There is a thread here something like cooling problems no more, that used to sell a kit, but that thread still has all the info you need to make your own kit, except the brackets. I did the kit, but opted to not use the brackets, when I realized the electric fan housing/shroud could be cut round and easily installed in the original fan shroud, cleanly and with providing much more space between the fan and front of the engine. i have posted pictures of how i mounted the fan here somewhere too. The electric fan is factory stock on some chevy cars, so is considered OEM reliable.

Toyota declined ordering parts of the TSB unless I provided my vin with the reason I wanted the parts (I only wanted the harness and relay box and body-plugs), i declined to void my warranty to purchase these parts, adn refuse to allow a dealer to work on my truck, unless catastrophic warranty claim; so I made my own harness, and used an open relay position in an existing relay box.

 

I’m curious about your setup with the intelligent relay control. How does that tie into the lingenfelter and what does it turn the fan up to? So if your engine is cold, but it’s hot outside, the fan will run at whatever you have the added relay signal set to turn the fan up to? Is that controlled at the lingenfelter or by some other method?

That said, like I’ve talked about in this thread, the factory setup doesn’t turn the condenser fan on very often (only around 95°+ and at high demand), so I still would think your fan isn’t turning on very often for AC?

Happy with the stock setup personally, but always interested to see what else works.

 

The 3rd gen AC uses a pressure sensor in the AC system, instead of a pressure switch. The AC computer monitors the AC pressure, to decide if the condenser would benefit from more fan; so how often the AC computer triggers aux fan, is contingent on many things, not just ambient T. It will depend on humidity (across the evaporator), ambient T, and Interior blower speed (airflow); which all affect the 'Load'

The lingenfelter control is extremely versatile, but i am running PWM fan speed control, with a water temperature sensor at the outlet (bottom) of the radiator; such that the electric fan only runs when the free-air cooling alone, is not adequate.

I put a resistor through a relay, in parallel with this water sensor, that tricks the lengenfelter control into thinking the water temperature is hotter, and run the fan harder. I think I assumed a hot day, cold radiator would be 85 deg, I have my control set to ramp up the fan when water leaving the radiator hits 130, so I think I used a resistor that increases the sensor reading by 60 deg, making the fan run immediately when the AC computer calls, even with a cold radiator (on a Hot day). Would need to look up what size resistor, but it works very well.

There is a secondary input wire on the Lengenfelter, that when triggered will run the fan at 100%, but I find that 100% is NEVER necessary. The cooling result of passing more air across the radiator, has a diminishing return, and the fan at 100% consumes considerable energy, to the tune of up to 2mpg (by my calculations); so what is the benefit of running it harder; other than some want the peace of mind that they have the best cooling possible. When the signal is removed from this Aux wire, the Lengenfelter defaults back to PWM curve from the water sensor.

The curve of the Lengenfelter control is programmable, you give it a start temp, and a Max temp, and in PWM mode, it runs a curve between the two settings. Is true that the fan does not seem to run very often, but the AC blowing hot at slow speeds and at initial start on a hot day; are corrected. Another reason the fan runs less, is that I have an oversize radiator, and have blocked off holes and air passages in the radiator support structure; to not allow any available free air to go around the radiator. This is also part of the same TSB, but Toyota would not sell me the plugs and fillers, I had to make my own.

 

After coming across this thread: https://www.tacomaworld.com/threads/pins-for-fusebox-relay-box.665358
I went ahead and ordered a fuse/relay box off eBay. I'll either use it to identify the pins or use some of the pins in it as pigtails to make my own harness. It'll also let me see how power is fed to the relay box and how it branches off to each relay.