Hey everyone,

I've been looking for the ambient temperature sensor for couple days. I can't seem to locate it. I ordered a new one from rock auto and it as arrived. So I have some idea what it looks like, but I can't find it on the car. It started reading -30 last fall.

It's a 2010 Nissan Sentra, automatic, 2.0 liter.

Can someone point me in the right direction on locating this thing on the vehicle?

Regards,

Jody

It's behind the grille on the vertical support underneath the Hood Latch, just south of the airbag Crash Zone Sensor (yellow connector, easy to recognize). There's a pretty clear drawing of the location here on DI-77, along with an ohm chart for the sensor:
https://www.nicoclub.com/service-manual ... 0%2FDI.pdf

Keep in mind that because it's in the grille, damaged wiring is just as likely as a bad sensor.

I have had the airbag crash zone sensor out. Thought that might be the ambient sensor until I actually held it. That is the only thing that is attached to that vertical support with wires going to it.

Then there's something odd going on, maybe a documentation screwup. The FSM actually shows two "ambients" on the "E" harness, E63 and E22, but the only one I could find in the WD's was labeled E63. However, the harness layout shows E22 in the spot illustrated on DI-77, not E63. E63 is shown in a different spot:

All I can tell you for sure is that it has to be up there someplace, Nissan ambient sensors going back to the 90's are always in the grille.

PS - It wouldn't be the first one I've seen ripped clear away by debris or collision, or chewed completely out by rodents. So check the E-Harness carefully for "used to be" wire nubs and ripped tape.

Yeah I'll take that Airbag crash zone sensor out again, see if there are wires in that harness that have been ripped away. I'd go check now but kid is gone in the car.

Thanks for the help VStar650CL. I'll let you know if I find anything tomorrow after noon

Looks like the sensor was hit by something, striped the wires back from the crash zone sensor. There is two wires there, light green with black strip, and black with white stripe. I would assume there are for the ambient temperature sensor.

Yep, that would be the ones. The sensors and connectors are pretty standard between models, so your best bet is to just grab a sensor at the U-Pullit. The sensors are RTD resistors with no polarity, so if the wire colors on the pigtail differ you can hook it up either way and it will still work. If you want to confirm the wiring is okay, short those two wires together and the temperature reading should go to max (that varies with firmware, but probably in the neighborhood of 140F).

I ordered the sensor plug on amazon.com. was 28 CAD with exchange. Right now it reads -30°C. Been like it since the fall

GreenGiant14 wrote: ↑

Wed Mar 16, 2022 3:00 pm

I ordered the sensor plug on amazon.com. was 28 CAD with exchange. Right now it reads -30°C. Been like it since the fall

It's a balance-resistor setup (voltage divider). There's a fixed pull-up resistor to 5V in the cluster, then the sensor acts as a variable pull-down. Ohm's Law determines what voltage exists at the junction, V = 5V * (1 / ((fixed + variable) / variable)). The sensors are all NTC (resistance drops as temperature rises), so grounding the input will pull it to 0V and make it read max hot, opening the circuit allows the fixed resistor to pull it to 5V and it reads max cold. That's why crossing the broken leads will effectively test the circuit. We actually see a lot of A/C problems caused by those types of sensors in Auto A/C systems. When they fail open-circuit the car thinks it's in Alaska and won't turn on the compressor.

When I joined the wires together it maxed out at 60°C. Kid informed me the air bag light is flashing. I disconnected the battery and took the crash sensor out and checked the wires, they are okay, no corrosion inside the plug. Could I have done something with that sensor by taking it off?

Sure, if you turned the key on while it was disconnected. That would cause an immediate code, and Nissan bag codes don't ever clear themselves. The light will stay on till the codes are cleared manually.