DIY: ECC Cabin Temperature Sensor 3524841 Removal/Replacement/Cleaning

Post by **bmdubya1198** » 08 Oct 2017, 14:58

There's probably a DIY floating around somewhere for this, but I had my camera handy and I figured it would be easy enough to write something up and hopefully help someone out who needs to clean or replace their ECC temp sensor. And another DIY writeup can only be a good thing, right?
I've had a code for a while for the ECC temperature sensor, and within the past few months it started buzzing constantly. I have cleaned it before through the vent with compressed air, but it must not have done much.
The buzzing finally got me irritated enough to pull it out and clean it a little more carefully, and lubricate the little fan to eliminate the buzzing sound.
This applies to the S70, V70, and C70. The 850 has a different setup.

The temperature sensor is located behind the small vent next to the switch panel with the sunroof and rear defrost switches. You may be able to clean off the dust through the vent with either a can of compressed air or an air compressor blow gun, but I decided to remove it to make cleaning it a little easier.

First thing you need to do is remove the radio, using the two tabs on the sides. Just push them in, with your finger nail or a coin and pull it right out. No need to disconnect the wires, just rest the head unit on the console. Put a towel or something over your shift knob if you’re worried about scratching it.

Reach behind the ECC unit and pull it forward to remove.Take note of the position of the connector prior to removal to make it easier to replace. The temp sensor is held in by four clips, two on top and two on bottom. If it’s a little stubborn, pivot it up and down a little bit. Disconnect the two green connectors and slide the radio back in place.

Now you should be able to see the temperature sensor to the left. Reach around and depress the two tabs and pull it back gently. It’s a little tricky to find the tabs at first, but once you pull it out, it’s much easier to see.
Then pull the connector and remove it from the car.

If you’re just replacing the sensor, skip the next two steps.

At this point, you’ll see the temperature sensor itself, and the fan in the bottom of the sensor. Use your choice of canned air or an air compressor to blow the dust out of the unit. I went ahead and sprayed the sensor with MAF sensor cleaner to make sure any dirt or dust was completely removed.

Now, in my case, the fan bearing was making an awful buzzing noise. I went ahead and used some CRC plastic-safe, electrical grade lubricant on the base of the fan and spun it around a bit to make sure it coated it completely. I sprayed more MAF sensor cleaner on the sensor and the plastic to try to prevent any lubricant from fouling the sensor and potentially damaging it. I’m not liable if you ruin your temperature sensor doing this!

At this point I reinstalled the sensor (just pop it back into place). Once you find the connectors for the ECC unit that most likely fell into your dash, reconnect it and push the unit back into place. It will click right in. Resecure the radio head unit if you didn’t already.

Turn on your car and enjoy the lack of buzzing! If your sensor was saved, your ECC unit should stop blinking at you that there is an error. Unfortunately mine did not, but I might just have to manually clear the ECC codes with Vol-FCR. Or the sensor is shot.

Anyway, I hope this will help out somebody!

Post by **wizechatmgr** » 08 Oct 2017, 16:29

Only thing I'd add to this is put a rag over your hands/arms as you're extracting the ECC unit otherwise you may get cut up as it suddenly releases without warning.

Great write up

Post by **bmdubya1198** » 08 Oct 2017, 18:05

wizechatmgr wrote: ↑08 Oct 2017, 16:29 Only thing I'd add to this is put a rag over your hands/arms as you're extracting the ECC unit otherwise you may get cut up as it suddenly releases without warning.

Great write up

Thanks!
Yeah, I watched Robert's video where he said he needed stitches after cutting his wrists on that trim. You have to be very careful pulling out the ECC unit.

Post by **scot850** » 11 Oct 2017, 10:48

Agreed, wear long sleeves and gloves. Gloves and sleeves for removing the ECC (850 is worse!) and long sleeves for removing the temp sensor as the ECC slot has sharp edges and likes to slice your forearm when reaching through the slot.

I wrote something on this a while ago, but this is a better version and the pictures are better too! Well done. This is a simple job to do in reality, but worth doing as most of these cars are up to 20 years old and the amount or airborne crud they have consumed over those years will amaze you! Only other point I would make is that the temp sensor unit does fail with age, so don't be surprised if cleaning it doesn't fix the issue.

Neil.

Post by **jvl** » 30 Mar 2018, 04:28

Great writeup, just cleaned my sensor and reinforced the b+ wire: no more blinky lights! Thanks!

Post by **abscate** » 30 Mar 2018, 05:26

Added part number 3524841 to title for search

This one fits the late P80 platform, 1998-2000, and the P80 platformed C70and S50cars

It’s an expensive part new, about $140

Post by **bmdubya1198** » 30 Mar 2018, 07:17

abscate wrote: ↑30 Mar 2018, 05:26 Added part number 3524841 to title for search

This one fits the late P80 platform, 1998-2000, and the P80 platformed C70and S50cars

It’s an expensive part new, about $140

Ouch, I feel I remember checking too, but I don't remember it being that much. That's crazy.

Post by **scot850** » 30 Mar 2018, 17:13

I will try and post to this thread again as the last time it didn't post!

When you remove the sensor from behind the dash, there is a rubber seal that clips into the front of the sensor and acts as a seal. it has x4 little tangs that clip in around the top edge. It generally gets stuck with gunge in the hole in the back of the dash. If you feel back there you will find it. Careful when pulling it out as it is easy to drop down the LHS of the center dash section requiring removal of the foot board on the drivers side to retrieve (how do I know.....?).

Neil.

Post by **bmdubya1198** » 30 Mar 2018, 17:22

scot850 wrote: ↑30 Mar 2018, 17:13 I will try and post to this thread again as the last time it didn't post!

When you remove the sensor from behind the dash, there is a rubber seal that clips into the front of the sensor and acts as a seal. it has x4 little tangs that clip in around the top edge. It generally gets stuck with gunge in the hole in the back of the dash. If you feel back there you will find it. Careful when pulling it out as it is easy to drop down the LHS of the center dash section requiring removal of the foot board on the drivers side to retrieve (how do I know.....?).

Neil.

I don't recall that seal, but great tip!

Post by **scot850** » 30 Mar 2018, 17:30

If you check this thread you can see it:

viewtopic.php?f=1&t=70611&hilit=Cabin+t ... ure+sensor

Neil.