reasons why Fan would not turn on?

[YoPaulyzSIck]

What could be the cause/reason of the fan not turning on? Fan is new..

[PbFut]

What could be the cause/reason of the fan not turning on? Fan is new..

Fuse, Relay, bad wire, bad ground, bad sensor.

[YoPaulyzSIck]

how would I check any of these.. Checked fuses they are fined , How do I check bad ground and relay? I have a feeling it could be a sensor since I had trouble putting it back into the radiator when I replaced it.. But before I go and buy a nnew sensor I'd like to make sure its not relay or bad ground.. How would I chek that?

[Rheins2020]

Do you have a multimeter?

[FredR]

If its the radiator fan start with checking the sending unit. If its the HVAC fan check the resistor located in the cowl accessed under the hood.

[FredR]

If its the radiator fan start with checking the sending unit. If its the HVAC fan check the resistor located in the cowl accessed under the hood.

[ronnie38]

On the right side of the radiator there is the elctric fan speed control sensor.
there are three pins. PPin One ground, two power control pins one for above 80 CC and one above 88 C. Pin 2 low speed pin 3 high speed. With key on I tested my fan by grounding pin 2 low speed fan, then also pin 3 high speed.
I live in south TX so I short pins 1, 2, and 3 together in the summer.

[Racerman27410]

try pushing in the A/C button and see if it runs.

[YoPaulyzSIck]

try pushing in the A/C button and see if it runs.

tried , does not turn.. Thats why Im asking..

[YoPaulyzSIck]

bump

[FredR]

I'm guessing its the Heat/Ventilation/Air Cond fan you are talking about. It is a very common problem for the fan resistor to fail. Usual symptoms are the fan will only work in the high speed. Fan resistor in located under the black plastic trim panel in the engine compartment that covers the windshield wiper linkage. Here is a link that shows how to replace. http://forums.bimmerforums.com/forum...ighlight=works

[FredR]

The rad fan should also work when a/c is on. Teach me not to assume.

[YoPaulyzSIck]

The rad fan should also work when a/c is on. Teach me not to assume.

So you telling me if I change the resister my radiator fan will work? because if the car was over heating before I changed my cracked radiator, the radiator fan would not turn on either.. It all falls under resister categorie?

[YoPaulyzSIck]

bump

[FredR]

The heat/ac fan has a resistor that fails. The rad fan doesn't have a resistor.

[YoPaulyzSIck]

The heat/ac fan has a resistor that fails. The rad fan doesn't have a resistor.

well Im gonna change the resister anyway, any idea why the radiator fan does not turn on?????

[Silberwald]

I'm not totally familiar with the Z3 fan system yet, but in GENERAL for a car's electrical cooling fan, there are a few things I would check in this order: Fuse, Fan, Relay, Thermoswitch

1. The Fuse for the fan - easy to do...right?
2. The Fan motor itself - take a car battery or a ~12V power tool battery and pigtail the battery into the plug that powers the fan. Switch the wires both ways to test the fan in both directions. If it wont turn, then the fan itself is the issue.

Once those are tested OK, move on to the relay and switch. the RELAY handles the full amperage that the fan requires... its kind of a big switch for the fan that is told to "turn on" or "turn off" by the little switch inside the THERMOSWITCH...the Thermoswitch is a lower amperage switch that trips when the coolant reaches a certain temp...Its usually screwed into the head or block somewhere.

3. The Relay that powers the fan...these can be tricky to test, and you'll need specific instructions for that relay, but they are often cheap enough to simply replace instead of troubleshooting.

4. If the Relay tests good, or a new Relay doesnt work, then move on to the Thermoswitch for the fan...often just two wires plug into it that transmit the "on" signal to trigger the relay, and these two wires can simply bridged together to kick the fan relay on...your ignition must be set to "on" for older cars. If tripping the wires makes the fan kick on, then the switch is bad and needs replacement.


Hope that helps, and good luck!

[YoPaulyzSIck]

I'm not totally familiar with the Z3 fan system yet, but in GENERAL for a car's electrical cooling fan, there are a few things I would check in this order: Fuse, Fan, Relay, Thermoswitch

1. The Fuse for the fan - easy to do...right?
2. The Fan motor itself - take a car battery or a ~12V power tool battery and pigtail the battery into the plug that powers the fan. Switch the wires both ways to test the fan in both directions. If it wont turn, then the fan itself is the issue.

Once those are tested OK, move on to the relay and switch. the RELAY handles the full amperage that the fan requires... its kind of a big switch for the fan that is told to "turn on" or "turn off" by the little switch inside the THERMOSWITCH...the Thermoswitch is a lower amperage switch that trips when the coolant reaches a certain temp...Its usually screwed into the head or block somewhere.

3. The Relay that powers the fan...these can be tricky to test, and you'll need specific instructions for that relay, but they are often cheap enough to simply replace instead of troubleshooting.

4. If the Relay tests good, or a new Relay doesnt work, then move on to the Thermoswitch for the fan...often just two wires plug into it that transmit the "on" signal to trigger the relay, and these two wires can simply bridged together to kick the fan relay on...your ignition must be set to "on" for older cars. If tripping the wires makes the fan kick on, then the switch is bad and needs replacement.


Hope that helps, and good luck!

where is thermoswitch located? and where is the relay located.. Cant be a fan, Its brand new..

[ronnie38]

where is thermoswitch located? and where is the relay located.. Cant be a fan, Its brand new..

On the right side of the radiator there is the elctric fan [COLOR=blue !important][COLOR=blue !important]speed [COLOR=blue !important]control[/COLOR][/COLOR][/COLOR] sensor.
there are three pins. PPin One ground, two power control pins one for above 80 CC and one above 88 C. Pin 2 low speed pin 3 high speed. With key on I tested my fan by grounding pin 2 low speed fan, then also pin 3 high speed.
I live in south TX so I short pins 1, 2, and 3 together in the summer.

[YoPaulyzSIck]

On the right side of the radiator there is the elctric fan [COLOR=blue !important][COLOR=blue !important]speed [COLOR=blue !important]control[/COLOR][/COLOR][/COLOR] sensor.
there are three pins. PPin One ground, two power control pins one for above 80 CC and one above 88 C. Pin 2 low speed pin 3 high speed. With key on I tested my fan by grounding pin 2 low speed fan, then also pin 3 high speed.
I live in south TX so I short pins 1, 2, and 3 together in the summer.

you have an image on how you short them out?

[ronnie38]

you have an image on how you short them out?

I dont have a photo right now, I took 3 resistor leads ((cut off of the resistors) soldered one end together and stuck the other ends in the connector sockets pins 1,2 and 3.
When I get home this afternoon I will take a photo of the jumper.

[YoPaulyzSIck]

I dont have a photo right now, I took 3 resistor leads ((cut off of the resistors) soldered one end together and stuck the other ends in the connector sockets pins 1,2 and 3.
When I get home this afternoon I will take a photo of the jumper.

thnk you..

[YoPaulyzSIck]

So I was told that even if the sensor does not work or disconected.. the radiator fan should still turn on when you press the AC button.. is this true? or false info?

[dion]

So I was told that even if the sensor does not work or disconected.. the radiator fan should still turn on when you press the AC button.. is this true? or false info?

Give it a try and let us know! As soon as you turn the key to the on position, hit the AC switch...

[YoPaulyzSIck]

Give it a try and let us know! As soon as you turn the key to the on position, hit the AC switch...

Thats the thing.. It does NOT turn on even when I have the AC button on... I had a little issue with that sensor. Placing it back in when I changed the radiator.. Thats why Im asking to make sure that sensor is a problem.. If the radiator fan should go on with AC button without having the sensor in then its a different issue...