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Cooling fan questions


cwsigmund

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I think the cooling fan on my '92 Lumina Euro 3.4 has stopped working for some reason. The car's temp is fine while I'm driving around, but when I stop and let the car idle for a couple minutes the temp goes up well over half way on the gauge. If I have to fix my fan anyway, I thought I'd ask about changing how it turns on.

 

What is the purpose of having the fan either on all the time, or having manual control over activating the fan?

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Jump the ALDL connector under the dash, and both fans should come on. See if both are coming on or not.

 

I personally wouldn't mess with an aux fan switch, the ECM controls the fans well enough, and if you try to get around it you'll just end up covering up a real problem with a band aide fix. The ECM fan control should be good enough.

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observed fan info!

 

this was well observed in a 95 ciera, and seems to be the same in all the 237,000 W's I have driven.

 

the drivers fan turns on at the 3/4 mark on the guage, with the a/c off.

the drivers fan turns on at the 1/2 mark on the guage, with the a/c on.

the passenger fan turns at the 3/4 mark, only if the a/c is on.

 

the marks do vary somewhat of course between cars... so the high mark may be 5/8.. etc...

 

basically the primary fan turns on a a lower set temp with the a/c on, expecting it to be hotter outside. otherwise.. you get the picture.

 

as suggested above, the best way to tell if the fans work is to jump the connector, which also tells the computer to cycle through it's check engine light, on the OBD 1.

 

if both fans work and the temp seems high... it may be a temp sensor

 

BTW.. contrary to what most people think, the fan phenominom actually makes the car run cooler if the a/c is on!

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observed fan info!

 

this was well observed in a 95 ciera, and seems to be the same in all the 237,000 W's I have driven.

 

the drivers fan turns on at the 3/4 mark on the guage, with the a/c off.

the drivers fan turns on at the 1/2 mark on the guage, with the a/c on.

the passenger fan turns at the 3/4 mark, only if the a/c is on.

 

the marks do vary somewhat of course between cars... so the high mark may be 5/8.. etc...

 

basically the primary fan turns on a a lower set temp with the a/c on, expecting it to be hotter outside. otherwise.. you get the picture.

 

as suggested above, the best way to tell if the fans work is to jump the connector, which also tells the computer to cycle through it's check engine light, on the OBD 1.

 

if both fans work and the temp seems high... it may be a temp sensor

 

BTW.. contrary to what most people think, the fan phenominom actually makes the car run cooler if the a/c is on!

 

I appreciate all ya'all's help, I'm such a noob when it comes to car mechanics....I probably shouldn't have picked a 3.4 w-body to learn with, but I'm stuck with her now :)

 

Forgive my ignorance, but what is the ALDL connector, and where can I find it? Can I jump it with a paperclip like I can use to check OBD1 codes?

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The fans come on while you are scanning codes.

Any time the paperclip is between A and B the fans should be on, and any codes will be flashing. Code 12 is the one that will flash if no codes are present.

A and B terminals are the top right terminals on the connector. If you arent sure just jump all of the pins next to the right top corner pin and one of them will work.

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The fans come on while you are scanning codes.

Any time the paperclip is between A and B the fans should be on, and any codes will be flashing. Code 12 is the one that will flash if no codes are present.

A and B terminals are the top right terminals on the connector. If you arent sure just jump all of the pins next to the right top corner pin and one of them will work.

 

Ok, cool. I'll have to try that in the morning. I have jumped the a and b before, so I know what to do now.

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