How to replace the interior temperature sensor
05-25-14, 02:03 PM
#1
Pole Position
Thread Starter
How to replace the interior temperature sensor
How to replace the interior temperature sensor. (Also useful if you should have to replace some of the dashboard switches)
The automatic temperature control in the GX depends on several inputs. The daylight sensor on top of the dash, the outside temperature sensor located in front of the radiator by the horns, and the inside temperature sensor behind the driver’s lower dashboard under the ignition key. And if you have the navigation system, it might also include the time of year, location, and time of day.
The sensor works by drawing interior air past a thermistor. It’s a special kind of resistor where the resistance varies in proportion to it’s temperature. This is used by the computer to determine how hot the return air from the cabin is. If your auto A/C has trouble maintaining the temperature, your thermistor might be bad. The part is cheap ($28) and less than the cost of a diagnosis at the dealer, so why not just replace it and see if your temperature regulation gets better?
Tools:
- Plastic trim removal tool (you can use a flat-bladed screwdriver or a putty knife if you’re careful)
- 10mm socket
- Philips head screwdriver
- Flashlight
P/N of the thermistor is: 88625-47021
1. Remove the driver’s floor mat
2. Remove the lower cover under the driver’s dashboard. There is a single philips-head screw near the center, under the TPMS selector switch. There is a claw on the right side near the transmission tunnel (easily visible you won’t miss it). There are two clips center and left. Pull straight down. Unclip the connector for the floorboard LED puddle light.
3. Remove the driver’s door scuff plate (the panel you step on/over). Use the trim tool and pry upwards, starting from the B-pillar near the seatbelt and working your way forward. It’s held in by multiple clips on the wiring tray underneath.
4. Remove the dead pedal. Pull hard up and out, first from the top, then from the bottom. There are white clips that grab onto the threads of some threaded studs welded to the body. Mine was already damaged (thanks, PO!) and I’ll need to order a replacement.
5. Remove the left kick panel. Unscrew the black plug revealed by the removal of the dead pedal. Pull straight back. There are two clips on the left side near the wiring.
6. Remove the “wood” trim on the left side of the dash using the trim tool. Pry from the bottom left corner. There are two clips.
7. Remove the trim ring around the ignition slot (the part with the arrow and says “push”). Use the trim tool.
8. Loosen the dash panel. Remove the 3 10mm bolts revealed earlier. Two are on the bottom, one is top-left. There are three clips along the top side. Pull straight back, but not all the way (all the wires are still connected on the back). You might need to loosen part of the door gasket for this.
9. Look for a corrugated plastic hose on the back of the instrument panel by the right side - that’s the hose that draws the return air through the thermistor. Unclip the wire connector, remove the thermistor from the panel (clips are on the sides) then remove the hose from the thermistor.
Reassembly is the reverse.
Two things to keep in mind:
1. If you loosened the door gasket, it goes over the dash panel, but under the kick panel.
2. When reinstalling the lower cover you have to look far under the dash near the brake pedal for the bracket that the back end of the lower cover slides into for it's support.
Chip H.
The automatic temperature control in the GX depends on several inputs. The daylight sensor on top of the dash, the outside temperature sensor located in front of the radiator by the horns, and the inside temperature sensor behind the driver’s lower dashboard under the ignition key. And if you have the navigation system, it might also include the time of year, location, and time of day.
The sensor works by drawing interior air past a thermistor. It’s a special kind of resistor where the resistance varies in proportion to it’s temperature. This is used by the computer to determine how hot the return air from the cabin is. If your auto A/C has trouble maintaining the temperature, your thermistor might be bad. The part is cheap ($28) and less than the cost of a diagnosis at the dealer, so why not just replace it and see if your temperature regulation gets better?
Tools:
- Plastic trim removal tool (you can use a flat-bladed screwdriver or a putty knife if you’re careful)
- 10mm socket
- Philips head screwdriver
- Flashlight
P/N of the thermistor is: 88625-47021
1. Remove the driver’s floor mat
2. Remove the lower cover under the driver’s dashboard. There is a single philips-head screw near the center, under the TPMS selector switch. There is a claw on the right side near the transmission tunnel (easily visible you won’t miss it). There are two clips center and left. Pull straight down. Unclip the connector for the floorboard LED puddle light.
3. Remove the driver’s door scuff plate (the panel you step on/over). Use the trim tool and pry upwards, starting from the B-pillar near the seatbelt and working your way forward. It’s held in by multiple clips on the wiring tray underneath.
4. Remove the dead pedal. Pull hard up and out, first from the top, then from the bottom. There are white clips that grab onto the threads of some threaded studs welded to the body. Mine was already damaged (thanks, PO!) and I’ll need to order a replacement.
5. Remove the left kick panel. Unscrew the black plug revealed by the removal of the dead pedal. Pull straight back. There are two clips on the left side near the wiring.
6. Remove the “wood” trim on the left side of the dash using the trim tool. Pry from the bottom left corner. There are two clips.
7. Remove the trim ring around the ignition slot (the part with the arrow and says “push”). Use the trim tool.
8. Loosen the dash panel. Remove the 3 10mm bolts revealed earlier. Two are on the bottom, one is top-left. There are three clips along the top side. Pull straight back, but not all the way (all the wires are still connected on the back). You might need to loosen part of the door gasket for this.
9. Look for a corrugated plastic hose on the back of the instrument panel by the right side - that’s the hose that draws the return air through the thermistor. Unclip the wire connector, remove the thermistor from the panel (clips are on the sides) then remove the hose from the thermistor.
Reassembly is the reverse.
Two things to keep in mind:
1. If you loosened the door gasket, it goes over the dash panel, but under the kick panel.
2. When reinstalling the lower cover you have to look far under the dash near the brake pedal for the bracket that the back end of the lower cover slides into for it's support.
Chip H.
The following users liked this post:
Rygar470 (07-02-19)
05-28-14, 05:30 PM
#2
Thanks Chip. Just FWIW, I did this and was able to skip steps 3, 4 and 5. I was able to get enough access to R&R the sensor this way. Just something to try if folks want to streamline.
05-29-14, 06:02 AM
#3
Pole Position
Thread Starter
I wasn't comfortable flexing the dash panel all that much (old plastics...).
Speaking of which, be careful with the dead pedal. I just ordered a replacement (from PO's damage). $78 ouch.
Chip H.
Speaking of which, be careful with the dead pedal. I just ordered a replacement (from PO's damage). $78 ouch.
Chip H.
07-02-19, 10:54 AM
#4
How to replace the interior temperature sensor. (Also useful if you should have to replace some of the dashboard switches)
The automatic temperature control in the GX depends on several inputs. The daylight sensor on top of the dash, the outside temperature sensor located in front of the radiator by the horns, and the inside temperature sensor behind the driver’s lower dashboard under the ignition key. And if you have the navigation system, it might also include the time of year, location, and time of day.
The sensor works by drawing interior air past a thermistor. It’s a special kind of resistor where the resistance varies in proportion to it’s temperature. This is used by the computer to determine how hot the return air from the cabin is. If your auto A/C has trouble maintaining the temperature, your thermistor might be bad. The part is cheap ($28) and less than the cost of a diagnosis at the dealer, so why not just replace it and see if your temperature regulation gets better?
Tools:
- Plastic trim removal tool (you can use a flat-bladed screwdriver or a putty knife if you’re careful)
- 10mm socket
- Philips head screwdriver
- Flashlight
P/N of the thermistor is: 88625-47021
1. Remove the driver’s floor mat
2. Remove the lower cover under the driver’s dashboard. There is a single philips-head screw near the center, under the TPMS selector switch. There is a claw on the right side near the transmission tunnel (easily visible you won’t miss it). There are two clips center and left. Pull straight down. Unclip the connector for the floorboard LED puddle light.
3. Remove the driver’s door scuff plate (the panel you step on/over). Use the trim tool and pry upwards, starting from the B-pillar near the seatbelt and working your way forward. It’s held in by multiple clips on the wiring tray underneath.
4. Remove the dead pedal. Pull hard up and out, first from the top, then from the bottom. There are white clips that grab onto the threads of some threaded studs welded to the body. Mine was already damaged (thanks, PO!) and I’ll need to order a replacement.
5. Remove the left kick panel. Unscrew the black plug revealed by the removal of the dead pedal. Pull straight back. There are two clips on the left side near the wiring.
6. Remove the “wood” trim on the left side of the dash using the trim tool. Pry from the bottom left corner. There are two clips.
7. Remove the trim ring around the ignition slot (the part with the arrow and says “push”). Use the trim tool.
8. Loosen the dash panel. Remove the 3 10mm bolts revealed earlier. Two are on the bottom, one is top-left. There are three clips along the top side. Pull straight back, but not all the way (all the wires are still connected on the back). You might need to loosen part of the door gasket for this.
9. Look for a corrugated plastic hose on the back of the instrument panel by the right side - that’s the hose that draws the return air through the thermistor. Unclip the wire connector, remove the thermistor from the panel (clips are on the sides) then remove the hose from the thermistor.
Reassembly is the reverse.
Two things to keep in mind:
1. If you loosened the door gasket, it goes over the dash panel, but under the kick panel.
2. When reinstalling the lower cover you have to look far under the dash near the brake pedal for the bracket that the back end of the lower cover slides into for it's support.
Chip H.
The automatic temperature control in the GX depends on several inputs. The daylight sensor on top of the dash, the outside temperature sensor located in front of the radiator by the horns, and the inside temperature sensor behind the driver’s lower dashboard under the ignition key. And if you have the navigation system, it might also include the time of year, location, and time of day.
The sensor works by drawing interior air past a thermistor. It’s a special kind of resistor where the resistance varies in proportion to it’s temperature. This is used by the computer to determine how hot the return air from the cabin is. If your auto A/C has trouble maintaining the temperature, your thermistor might be bad. The part is cheap ($28) and less than the cost of a diagnosis at the dealer, so why not just replace it and see if your temperature regulation gets better?
Tools:
- Plastic trim removal tool (you can use a flat-bladed screwdriver or a putty knife if you’re careful)
- 10mm socket
- Philips head screwdriver
- Flashlight
P/N of the thermistor is: 88625-47021
1. Remove the driver’s floor mat
2. Remove the lower cover under the driver’s dashboard. There is a single philips-head screw near the center, under the TPMS selector switch. There is a claw on the right side near the transmission tunnel (easily visible you won’t miss it). There are two clips center and left. Pull straight down. Unclip the connector for the floorboard LED puddle light.
3. Remove the driver’s door scuff plate (the panel you step on/over). Use the trim tool and pry upwards, starting from the B-pillar near the seatbelt and working your way forward. It’s held in by multiple clips on the wiring tray underneath.
4. Remove the dead pedal. Pull hard up and out, first from the top, then from the bottom. There are white clips that grab onto the threads of some threaded studs welded to the body. Mine was already damaged (thanks, PO!) and I’ll need to order a replacement.
5. Remove the left kick panel. Unscrew the black plug revealed by the removal of the dead pedal. Pull straight back. There are two clips on the left side near the wiring.
6. Remove the “wood” trim on the left side of the dash using the trim tool. Pry from the bottom left corner. There are two clips.
7. Remove the trim ring around the ignition slot (the part with the arrow and says “push”). Use the trim tool.
8. Loosen the dash panel. Remove the 3 10mm bolts revealed earlier. Two are on the bottom, one is top-left. There are three clips along the top side. Pull straight back, but not all the way (all the wires are still connected on the back). You might need to loosen part of the door gasket for this.
9. Look for a corrugated plastic hose on the back of the instrument panel by the right side - that’s the hose that draws the return air through the thermistor. Unclip the wire connector, remove the thermistor from the panel (clips are on the sides) then remove the hose from the thermistor.
Reassembly is the reverse.
Two things to keep in mind:
1. If you loosened the door gasket, it goes over the dash panel, but under the kick panel.
2. When reinstalling the lower cover you have to look far under the dash near the brake pedal for the bracket that the back end of the lower cover slides into for it's support.
Chip H.
Thanks Chip.
07-03-19, 01:53 PM
#5
Pole Position
Thread Starter
I originally found it on Butler Lexus' parts site but they no longer list older Lexus models. But I searched & found it on mylparts.com. They claim it's used in 140+ different model+year combinations so appears to be a common Toyota part.
https://www.mylparts.com/oem-parts/l...00NzAyMQ%3D%3D
The symptoms were the auto A/C wouldn't hold the correct temperature.
Chip H.
https://www.mylparts.com/oem-parts/l...00NzAyMQ%3D%3D
The symptoms were the auto A/C wouldn't hold the correct temperature.
Chip H.
The following users liked this post:
Rygar470 (07-03-19)
07-06-19, 05:38 PM
#6
I originally found it on Butler Lexus' parts site but they no longer list older Lexus models. But I searched & found it on mylparts.com. They claim it's used in 140+ different model+year combinations so appears to be a common Toyota part.
https://www.mylparts.com/oem-parts/l...00NzAyMQ%3D%3D
The symptoms were the auto A/C wouldn't hold the correct temperature.
Chip H.
https://www.mylparts.com/oem-parts/l...00NzAyMQ%3D%3D
The symptoms were the auto A/C wouldn't hold the correct temperature.
Chip H.
Hmm.. I never bother to use the "Auto" feature, but I do have a code(As mentioned in my " B1252" thread) which from all the reading I've done on the web, points to this region. Trying to decide if I should go ahead and change this sensor or leave it be.
07-07-19, 03:32 AM
#7
Pole Position
Thread Starter
Have you tried cleaning it? Because it sucks air past, it's not uncommon for it to get clogged with lint & gunk.
Chip H.
Chip H.
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07-08-19, 07:20 PM
#8
No but I took a 2 hour trip over the 4th/weekend, with a tiny bit of "off-the-beaten-path" type of traveling. came back home, scanned it and the sucker has zero codes again... I scanned it 3 more times over the course of the past few days, and still nothing..
When I get a chance, I'll try to tear into her and try to clean said part.
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