87 300e aux fan not working right.
07-24-2008, 03:09 AM
#1
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87 300E
87 300e aux fan not working right.
so the electric fan in front of the radiator has recently decided to not come on when its supposed too. its not a big deal until i get stuck in traffic and it doesnt come on and my car starts heating up( past 100c). i rigged it up with a switch strraight to the battery and it works fine but id really like it to work on its own.
could it be the engine temp sensor or a relay or what?
thanks for any help or advice you guys have.
could it be the engine temp sensor or a relay or what?
thanks for any help or advice you guys have.
07-10-2009, 01:57 AM
#3
Super Member
Hopefully this may help someone who has this problem today:
TO CHECK TO SEE IF BOTH AUXILIARY FANS ARE WORKING DO THIS TEST:
Step 1 - With the car off, insert key and turn ignition to the second position where the lights are lit up on the dash.
Step 2 - Press and hold both "Auto" buttons on the Climate Control unit for approx. 10 seconds and then let go (Try it again at 15 seconds if this test does not work the first time with 10 seconds).
- Both Black Auxiliary Fans should turn on and spin.
If only one fan spins, you may have a problem with the fan itself, the fan relay or a circuit to the fan. The chances that both fans do not spin during this test is very slim as both fans should not break around the same time.
The issue that I had was that the Driver's side Auxiliary Fan was shot and did not spin during the test. The Passenger side auxiliary fan was spinning. So, I swaped out the driver's side fan and viola. Fixed - spins. Comes on at approx. 103 cel and shuts off at 98 cel.
Another tip if your car starts to overheat while driving is to manually turn on the fans by doing Step 2 above while driving - this can save your engine/head gasket. My stealership thought that it was the viscous fan clutch and recommended that I change that, the Fan Relay, Thermostat and flush the coolant and then change the Coolant Sensor if the problem was still there. That easily would have been $600-$800. Morons.
Hope that this helps someone.
TO CHECK TO SEE IF BOTH AUXILIARY FANS ARE WORKING DO THIS TEST:
Step 1 - With the car off, insert key and turn ignition to the second position where the lights are lit up on the dash.
Step 2 - Press and hold both "Auto" buttons on the Climate Control unit for approx. 10 seconds and then let go (Try it again at 15 seconds if this test does not work the first time with 10 seconds).
- Both Black Auxiliary Fans should turn on and spin.
If only one fan spins, you may have a problem with the fan itself, the fan relay or a circuit to the fan. The chances that both fans do not spin during this test is very slim as both fans should not break around the same time.
The issue that I had was that the Driver's side Auxiliary Fan was shot and did not spin during the test. The Passenger side auxiliary fan was spinning. So, I swaped out the driver's side fan and viola. Fixed - spins. Comes on at approx. 103 cel and shuts off at 98 cel.
Another tip if your car starts to overheat while driving is to manually turn on the fans by doing Step 2 above while driving - this can save your engine/head gasket. My stealership thought that it was the viscous fan clutch and recommended that I change that, the Fan Relay, Thermostat and flush the coolant and then change the Coolant Sensor if the problem was still there. That easily would have been $600-$800. Morons.
Hope that this helps someone.
07-30-2009, 11:26 AM
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95' AMG SeeThreeSix
Hopefully this may help someone who has this problem today:
TO CHECK TO SEE IF BOTH AUXILIARY FANS ARE WORKING DO THIS TEST:
Step 1 - With the car off, insert key and turn ignition to the second position where the lights are lit up on the dash.
Step 2 - Press and hold both "Auto" buttons on the Climate Control unit for approx. 10 seconds and then let go (Try it again at 15 seconds if this test does not work the first time with 10 seconds).
- Both Black Auxiliary Fans should turn on and spin.
If only one fan spins, you may have a problem with the fan itself, the fan relay or a circuit to the fan. The chances that both fans do not spin during this test is very slim as both fans should not break around the same time.
The issue that I had was that the Driver's side Auxiliary Fan was shot and did not spin during the test. The Passenger side auxiliary fan was spinning. So, I swaped out the driver's side fan and viola. Fixed - spins. Comes on at approx. 103 cel and shuts off at 98 cel.
Another tip if your car starts to overheat while driving is to manually turn on the fans by doing Step 2 above while driving - this can save your engine/head gasket. My stealership thought that it was the viscous fan clutch and recommended that I change that, the Fan Relay, Thermostat and flush the coolant and then change the Coolant Sensor if the problem was still there. That easily would have been $600-$800. Morons.
Hope that this helps someone.
TO CHECK TO SEE IF BOTH AUXILIARY FANS ARE WORKING DO THIS TEST:
Step 1 - With the car off, insert key and turn ignition to the second position where the lights are lit up on the dash.
Step 2 - Press and hold both "Auto" buttons on the Climate Control unit for approx. 10 seconds and then let go (Try it again at 15 seconds if this test does not work the first time with 10 seconds).
- Both Black Auxiliary Fans should turn on and spin.
If only one fan spins, you may have a problem with the fan itself, the fan relay or a circuit to the fan. The chances that both fans do not spin during this test is very slim as both fans should not break around the same time.
The issue that I had was that the Driver's side Auxiliary Fan was shot and did not spin during the test. The Passenger side auxiliary fan was spinning. So, I swaped out the driver's side fan and viola. Fixed - spins. Comes on at approx. 103 cel and shuts off at 98 cel.
Another tip if your car starts to overheat while driving is to manually turn on the fans by doing Step 2 above while driving - this can save your engine/head gasket. My stealership thought that it was the viscous fan clutch and recommended that I change that, the Fan Relay, Thermostat and flush the coolant and then change the Coolant Sensor if the problem was still there. That easily would have been $600-$800. Morons.
Hope that this helps someone.
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05-17-2010, 02:12 AM
#8
Just found this thread.
The original method says press and hold "both" auto buttons. What about the earlier ones that only have 1 auto button? Is this ability still possible?
The original method says press and hold "both" auto buttons. What about the earlier ones that only have 1 auto button? Is this ability still possible?
05-17-2010, 09:12 AM
#9
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1993 300D turbo
Auxiliary fan not working
This tip is fantastic!
Thank you much.
Is that tip somewhere in a manual?
OldBeaver
Thank you much.
Is that tip somewhere in a manual?
OldBeaver
Hopefully this may help someone who has this problem today:
TO CHECK TO SEE IF BOTH AUXILIARY FANS ARE WORKING DO THIS TEST:
Step 1 - With the car off, insert key and turn ignition to the second position where the lights are lit up on the dash.
Step 2 - Press and hold both "Auto" buttons on the Climate Control unit for approx. 10 seconds and then let go (Try it again at 15 seconds if this test does not work the first time with 10 seconds).
- Both Black Auxiliary Fans should turn on and spin.
If only one fan spins, you may have a problem with the fan itself, the fan relay or a circuit to the fan. The chances that both fans do not spin during this test is very slim as both fans should not break around the same time.
The issue that I had was that the Driver's side Auxiliary Fan was shot and did not spin during the test. The Passenger side auxiliary fan was spinning. So, I swaped out the driver's side fan and viola. Fixed - spins. Comes on at approx. 103 cel and shuts off at 98 cel.
Another tip if your car starts to overheat while driving is to manually turn on the fans by doing Step 2 above while driving - this can save your engine/head gasket. My stealership thought that it was the viscous fan clutch and recommended that I change that, the Fan Relay, Thermostat and flush the coolant and then change the Coolant Sensor if the problem was still there. That easily would have been $600-$800. Morons.
Hope that this helps someone.
TO CHECK TO SEE IF BOTH AUXILIARY FANS ARE WORKING DO THIS TEST:
Step 1 - With the car off, insert key and turn ignition to the second position where the lights are lit up on the dash.
Step 2 - Press and hold both "Auto" buttons on the Climate Control unit for approx. 10 seconds and then let go (Try it again at 15 seconds if this test does not work the first time with 10 seconds).
- Both Black Auxiliary Fans should turn on and spin.
If only one fan spins, you may have a problem with the fan itself, the fan relay or a circuit to the fan. The chances that both fans do not spin during this test is very slim as both fans should not break around the same time.
The issue that I had was that the Driver's side Auxiliary Fan was shot and did not spin during the test. The Passenger side auxiliary fan was spinning. So, I swaped out the driver's side fan and viola. Fixed - spins. Comes on at approx. 103 cel and shuts off at 98 cel.
Another tip if your car starts to overheat while driving is to manually turn on the fans by doing Step 2 above while driving - this can save your engine/head gasket. My stealership thought that it was the viscous fan clutch and recommended that I change that, the Fan Relay, Thermostat and flush the coolant and then change the Coolant Sensor if the problem was still there. That easily would have been $600-$800. Morons.
Hope that this helps someone.
07-29-2013, 01:26 AM
#10
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1998 E300 TD
Thank you for this tip, the test worked. My problem is the aux fans have not been going to high speed and the car overheated. The test triggered the fans to cycle ... from stop, start to accelerate, then stop and repeat. The highest speed achieved is better than before though. Any thought ?
Thank you much,
hikingmapa
Thank you much,
hikingmapa
07-29-2013, 04:11 PM
#11
Out Of Control!!
Thank you for this tip, the test worked. My problem is the aux fans have not been going to high speed and the car overheated. The test triggered the fans to cycle ... from stop, start to accelerate, then stop and repeat. The highest speed achieved is better than before though. Any thought ?
Thank you much,
hikingmapa
Thank you much,
hikingmapa
Typically the aux fan only engages when the engine coolant is grater than 104C and or the refrigerant temp exceeds a set temp(I forgot the value).Therefore it is not designed to be on all the time.
The two fan system is very simple---you have the one fan and the motor then a small drive belt connects and drives the second fan---therefore if only one motor driven fan engages---the drive belt is faulty.
If they both wont engage and the belt is good and the connection is not corroded then the fan controller or relay is faulty.
08-13-2013, 04:30 PM
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1987 300e
In my '87 300E, there's a .2-ohm resistor just below the left headlight housing. It's a tan, rectangular thing with 2 wires screwed into it (one at each end). It was cracked (and fell apart completely when I removed it.) Replacing this very inexpensive part, if it's worn/defective is a good idea. It was in series with the fan...
