IPD sale Volvo Parts Volvo Parts guaranteed for life Volvo Parts

Testing cabin temp sensor fan motor

Help, Advice and DIY Tutorials on Volvo's extremely popular car line -- Volvo's 1990s "bread and butter" cars -- powered by the ubiquitous and durable Volvo inline 5-cylinder engine.
1992 - 1997 850, 850 R, 850 T5-R, 850 T5, 850 GLT
1997 - 2000 S70, S70 AWD
1997 - 2000 V70, V70 AWD
1997 - 2000 V70-XC
1997 - 2004 C70
scot850
Posts: 4100
Joined: Mon Apr 05, 2010 2:46 pm
Year and Model: 2000 V70 R
Location: Calgary, Alberta, Canada
Been thanked: 25 times
Canada

Testing cabin temp sensor fan motor

Post by scot850 » Thu Oct 19, 2017 4:47 pm

I planned to install the bag of spare cabin temp sensors to check they work. However, as they are a pain to access requiring removing the radio and ECC unit to get to it each time, I want to check the sensor fan actually runs before installing them as otherwise it is a waste of time. I suppose I could just try to connect each one with the connector without actually installing the ECC fully, but I thought I could shortlist them by say connecting a 9V cell across the live and ground terminals hoping it is enough power just to spin the fan.

Problem is the wiring diagram I have has the heating circuit but for some reason this does not include the temp sensor and it's 4 pin connector. Can anyone tell me which wires to the connector have which function so I can try to see if this would work?

I have also considered just check the fans work and just sell all the spares as a 2 for 1 as the chances of 2 being bad are low.

I'm also thinking if I wanted to be thorough, I could use a thermal temp sensor to check the temp output at one vent and at a set temp to see how accurate the temp sensors are relative to each others.

Thoughts and help on identifying the wire/pins is appreciated.

Neil.


1993 850 GLT -Sold
1998 V70 XC - Sold
2000 V70 R - still being an endless PITA
2006 XC70
1997 Volvo 850 SE NA - Went to niece in California
2000 V70 SE NA - New project and test bed

User avatar
BEJinFbk
Posts: 3427
Joined: Sat Jan 05, 2008 10:32 pm
Year and Model: '98 V70 R
Location: Fairbanks, Alaska
Been thanked: 4 times
United States of America

Re: Testing cabin temp sensor fan motor

Post by BEJinFbk » Thu Oct 19, 2017 11:51 pm

Hey, Neil -
From what I see, you've got:

Motor Ground - Pin 2 - Black
Motor Power - Pin 4 - Yellow/Red

Thermistor - Pin 3 - Brown/White
Thermistor - Pin 5 - Yellow

Hope this Helps. Cheers!


'98 V70 R - Well Equipped for Life Up North... ;)

scot850
Posts: 4100
Joined: Mon Apr 05, 2010 2:46 pm
Year and Model: 2000 V70 R
Location: Calgary, Alberta, Canada
Been thanked: 25 times
Canada

Re: Testing cabin temp sensor fan motor

Post by scot850 » Fri Oct 20, 2017 8:04 am

Thanks my northern friend! That really helps! Now all I have to do is pull it all apart at least once to find the connector and which pins they go to on the unit. I couldn't have figured this out myself so thanks again!

Neil.


1993 850 GLT -Sold
1998 V70 XC - Sold
2000 V70 R - still being an endless PITA
2006 XC70
1997 Volvo 850 SE NA - Went to niece in California
2000 V70 SE NA - New project and test bed

User avatar
BEJinFbk
Posts: 3427
Joined: Sat Jan 05, 2008 10:32 pm
Year and Model: '98 V70 R
Location: Fairbanks, Alaska
Been thanked: 4 times
United States of America

Re: Testing cabin temp sensor fan motor

Post by BEJinFbk » Fri Oct 20, 2017 3:02 pm

Always happy to help. :mrgreen:
Is this something that you can use ... ?
Screen Shot 2017-10-20 at 12.59.07 PM.png
Screen Shot 2017-10-20 at 12.59.07 PM.png (22.12 KiB) Viewed 147 times


'98 V70 R - Well Equipped for Life Up North... ;)

scot850
Posts: 4100
Joined: Mon Apr 05, 2010 2:46 pm
Year and Model: 2000 V70 R
Location: Calgary, Alberta, Canada
Been thanked: 25 times
Canada

Re: Testing cabin temp sensor fan motor

Post by scot850 » Fri Oct 20, 2017 6:48 pm

I'll give it a whirl with a 9V battery and a couple of leads and see what happens. I'll report back. Weird how they list 5 pins but there are only 4 in the unit. Only electrickery people would do that to confuse us mere mortals!

Thanks again!

Neil.


1993 850 GLT -Sold
1998 V70 XC - Sold
2000 V70 R - still being an endless PITA
2006 XC70
1997 Volvo 850 SE NA - Went to niece in California
2000 V70 SE NA - New project and test bed

User avatar
BEJinFbk
Posts: 3427
Joined: Sat Jan 05, 2008 10:32 pm
Year and Model: '98 V70 R
Location: Fairbanks, Alaska
Been thanked: 4 times
United States of America

Re: Testing cabin temp sensor fan motor

Post by BEJinFbk » Fri Oct 20, 2017 7:04 pm

We do what we can!
Possibly, they chose that to be sure that
it was different from nearby connectors.


'98 V70 R - Well Equipped for Life Up North... ;)

scot850
Posts: 4100
Joined: Mon Apr 05, 2010 2:46 pm
Year and Model: 2000 V70 R
Location: Calgary, Alberta, Canada
Been thanked: 25 times
Canada

Re: Testing cabin temp sensor fan motor

Post by scot850 » Sat Oct 21, 2017 5:43 pm

So using the info supplied, I used a 9V battery and wired 2 leads to it and a couple of small screwdrivers clamped to the other ends. Touched the #4 pin with the +ve lead and #2 pin with the -ve lead and then watched for the motors spinning. I have 9 (yes 9!!) of these cabin temp sensors and all of them have been cleaned and lubed. All thankfully run nicely.

Also decided to do a resistance test. On my cheapo multitester, this can only be read in continuity mode. 6/9 gave a resistance of approx. 12.6 ohms +/- 0.05, and the other 3 strangely all read 12.9 +/- 0.5 ohms across the motor contacts.

So at least they all have good running fan motors. Does a resistance difference of 0.3 ohms make much difference?

Tried taking a resistance across the 2 pins for the thermocouple (pins #3 and #5) but go no response. Thought I might get a value like with the engine temp sensor, but nothing on any of them.

Neil.


1993 850 GLT -Sold
1998 V70 XC - Sold
2000 V70 R - still being an endless PITA
2006 XC70
1997 Volvo 850 SE NA - Went to niece in California
2000 V70 SE NA - New project and test bed

User avatar
jreed
Posts: 993
Joined: Sun Mar 08, 2009 5:43 am
Year and Model: '97 Volvo 855 GLT
Location: RTP, North Carolina
Has thanked: 1 time
United States of America

Re: Testing cabin temp sensor fan motor

Post by jreed » Sun Oct 22, 2017 6:39 am

I've got an 850 so the info may not apply to the V70, but the duct and cabin sensors on the 850 should generally measure in the 8-12kOhms range. I wrote up a easy way to test them all quickly here:
https://www.matthewsvolvosite.com/forum ... hp?t=50443


1997 855 GLT (Light Pressure Turbo) still going strong. Previous: 1986 240 GL rusted out in '06, 1985 Saab 900T rusted out in '95, 1975 Saab 99 rusted out in '95, 1973 Saab 99 rusted out in '94

User avatar
abscate
MVS Moderator
Posts: 11173
Joined: Sun Feb 17, 2013 5:54 pm
Year and Model: 1999 V70T5, 2005 V70
Location: NYC
Has thanked: 21 times
Been thanked: 27 times
Trinidad & Tobago

Re: Testing cabin temp sensor fan motor

Post by abscate » Sun Oct 22, 2017 8:45 am

scot850 wrote:
Sat Oct 21, 2017 5:43 pm
So using the info supplied, I used a 9V battery and wired 2 leads to it and a couple of small screwdrivers clamped to the other ends. Touched the #4 pin with the +ve lead and #2 pin with the -ve lead and then watched for the motors spinning. I have 9 (yes 9!!) of these cabin temp sensors and all of them have been cleaned and lubed. All thankfully run nicely.

Also decided to do a resistance test. On my cheapo multitester, this can only be read in continuity mode. 6/9 gave a resistance of approx. 12.6 ohms +/- 0.05, and the other 3 strangely all read 12.9 +/- 0.5 ohms across the motor contacts.

So at least they all have good running fan motors. Does a resistance difference of 0.3 ohms make much difference?

Tried taking a resistance across the 2 pins for the thermocouple (pins #3 and #5) but go no response. Thought I might get a value like with the engine temp sensor, but nothing on any of them.

Neil.
That resistance difference won't matter,and is probably less than the error in even a pretty good meter, no fluke intended.


1 SWMBO for 30 years
2 Volvos
3 VWs
4 Careers
5 cats/dogs/gears
6 Perfect Ladies in waiting
7 Drivers
8 Boats- with a big pointy metal thing on top

1999 V70 T5M 56 2005 V70 NA M56 VWs BMW

scot850
Posts: 4100
Joined: Mon Apr 05, 2010 2:46 pm
Year and Model: 2000 V70 R
Location: Calgary, Alberta, Canada
Been thanked: 25 times
Canada

Re: Testing cabin temp sensor fan motor

Post by scot850 » Sun Oct 22, 2017 9:09 am

Thanks guys (and yes the pun was received abscate!).

jreed, thanks for all the info. I need to spend some time reading it for the detail. I like the duct temp sensor info as I know I have some of those kicking around too somewhere!

What I found strange was I was getting no resistance reading on the temp sensor pins which I was hoping to use to see if they are all reading in the same range for temperature. Then that would mean I would be able to carry out 'field' test at PnP when pulling parts for all the sensors. It is a 50km round trip to the 2 x PnP from my house so a pain/expensive to return parts that are only found to be faulty later. I could even test the parts in the car after buying and return them right away if needed.

When testing the cabin temp sensors (I am no electrical genius) on the resistance settings all I got was a 1. on all settings.

Many thanks,

Neil.


1993 850 GLT -Sold
1998 V70 XC - Sold
2000 V70 R - still being an endless PITA
2006 XC70
1997 Volvo 850 SE NA - Went to niece in California
2000 V70 SE NA - New project and test bed

Post Reply

Return to “Volvo 850, S70, V70, C70 & V70-XC Forum (1992-2000)”

Who is online

Users browsing this forum: Google Adsense [Bot], kahl, tryingbe and 46 guests