Location of Fan Thermo-Switch 1998 940

dibbles00 · Aug 9th, 2011, 14:01

Hi,
Can anyone point me in the direction of the thermo-switch for the 1998 Volvo 940 LPT please?

Thanks in advance,
Dee

PS I read that if the fan does not switch on then it is either this or the block temp sensor? Any input would be great.

dibbles00 · Aug 9th, 2011, 14:14

http://www.volvoclub.org.uk/faq/Cool...ngFanOperation

According to this site there is no thermal switch on the later 940's only a block temp sensor?

Could anyone please point me in the direction of it please?

"In later 940s, the coolant fan is controlled by either the high and low pressure air conditioning sensors on the condensor outlet and the ECU block temp sensor: there is no independent radiator fan sensor. If the fan fails, check the fan relay behind the left side headlight first. "

wooble · Aug 9th, 2011, 14:52

Basically the fan is controlled from the ECU via the fan relay behind the passenger side headlight. The ECU reads the engine temperature from a sensor in the cylinder head on the passenger side, underneath the intake port for cylinder 3. If this sensor is faulty, the car will run far too rich and will probably show a check engine light.

There's also another temperature sensor for the dash gauge under the port for cylinder 2, this has no connection to the ECU or fan.

dibbles00 · Aug 9th, 2011, 18:33

Hiya,
Thanks for your help with this. Quick question please: Is cylinder port 1 at the front bumper end or is it at the dash/firewall end. I've put two scenarios below to help with what I mean.

Scenario 1 = [Bumper] (1) (2) (3) (4) [Firewall/Dash]

Or

Scenario 2 = [Bumper] (4) (3) (2) (1) [Firewall/Dash]

Thanks again,
Dee

PS I've located the two plugs with your help - 1 has a square fitting plug like this [], which is towards the bumper/front lights side. The other has a square bottom and a half moon top like this (], which is located at the firewall/dash side.

wooble · Aug 9th, 2011, 21:05

Cylinder 1 is the front of the engine, i.e. the end closest to the bumper.

The ECU sensor has a small square plug / square pins and is normally under no.3 and the gauge sensor has the larger half moon / round pins is normally under no.2.

I'll make a post in your other thread about diagnosing fan probs.

dibbles00 · Aug 9th, 2011, 23:35

Thank you ever so much for all of your help with this issue Wooble

You are a genius! I have ordered the ECU switch from Eurocar parts and will change it over tomorrow when it arrives at 8am.

Thank you so, so much!

Aug 9th, 2011, 14:01	#1
dibbles00 New Member Last Online: Oct 28th, 2017 07:33 Join Date: Jul 2011 Location: Birmingham	Location of Fan Thermo-Switch 1998 940 Hi, Can anyone point me in the direction of the thermo-switch for the 1998 Volvo 940 LPT please? Thanks in advance, Dee PS I read that if the fan does not switch on then it is either this or the block temp sensor? Any input would be great.

Aug 9th, 2011, 14:52	#3
wooble Stay gold baby! Last Online: Jul 24th, 2022 16:15 Join Date: May 2009 Location: Bristol	Basically the fan is controlled from the ECU via the fan relay behind the passenger side headlight. The ECU reads the engine temperature from a sensor in the cylinder head on the passenger side, underneath the intake port for cylinder 3. If this sensor is faulty, the car will run far too rich and will probably show a check engine light. There's also another temperature sensor for the dash gauge under the port for cylinder 2, this has no connection to the ECU or fan. __________________ Click to see 240 parts I want to give you money for!

Aug 9th, 2011, 18:33	#4
dibbles00 New Member Last Online: Oct 28th, 2017 07:33 Join Date: Jul 2011 Location: Birmingham	Hiya, Thanks for your help with this. Quick question please: Is cylinder port 1 at the front bumper end or is it at the dash/firewall end. I've put two scenarios below to help with what I mean. Scenario 1 = [Bumper] (1) (2) (3) (4) [Firewall/Dash] Or Scenario 2 = [Bumper] (4) (3) (2) (1) [Firewall/Dash] Thanks again, Dee PS I've located the two plugs with your help - 1 has a square fitting plug like this [], which is towards the bumper/front lights side. The other has a square bottom and a half moon top like this (], which is located at the firewall/dash side. Last edited by dibbles00; Aug 9th, 2011 at 18:40. Reason: Plug connectors at the bottom

Aug 9th, 2011, 21:05	#5
wooble Stay gold baby! Last Online: Jul 24th, 2022 16:15 Join Date: May 2009 Location: Bristol	Cylinder 1 is the front of the engine, i.e. the end closest to the bumper. The ECU sensor has a small square plug / square pins and is normally under no.3 and the gauge sensor has the larger half moon / round pins is normally under no.2. I'll make a post in your other thread about diagnosing fan probs. __________________ Click to see 240 parts I want to give you money for! Last edited by wooble; Aug 9th, 2011 at 21:13.

Aug 9th, 2011, 14:14	#2
dibbles00 New Member Last Online: Oct 28th, 2017 07:33 Join Date: Jul 2011 Location: Birmingham	http://www.volvoclub.org.uk/faq/Cool...ngFanOperation According to this site there is no thermal switch on the later 940's only a block temp sensor? Could anyone please point me in the direction of it please? "In later 940s, the coolant fan is controlled by either the high and low pressure air conditioning sensors on the condensor outlet and the ECU block temp sensor: there is no independent radiator fan sensor. If the fan fails, check the fan relay behind the left side headlight first. "

Aug 9th, 2011, 23:35	#6
dibbles00 New Member Last Online: Oct 28th, 2017 07:33 Join Date: Jul 2011 Location: Birmingham	Thank you ever so much for all of your help with this issue Wooble You are a genius! I have ordered the ECU switch from Eurocar parts and will change it over tomorrow when it arrives at 8am. Thank you so, so much!

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