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  #1  
Old 05-08-2001, 02:17 PM
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Location: Dallas, Texas
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Had the head gasket changed and valve job done in the 300E. WOW what a difference. My question is about the fans. When the car gets to 90deg, one of the front fans kicks on (pass side). When I turn on the A/C, NEITHER of the fans kicks on. Is it the switch on the drier, or is it the fan? I know the way my 300TD works, but am not as familiar with this car. I'm taking it back to the mechanic to have the idle adjusted, but would like to solve this one myself. He thinks the fan is out, but I am hoping for the switch.
1. Is there an easy way to bypass to check the (drivers side) fan?
2. If it is the fan, how difficult is it to change the fan?

Any suggestions would be of GREAT assistance. The car cools fine when in traffic with the A/C off, runs REAL hot with the A/C on.
Thanks!
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88 BMW E32 735i (make it go away)
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  #2  
Old 05-08-2001, 06:04 PM
John CH
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R Talley,
I hope you get a response to your fan/cooling issue. My 92 300E is doing the same thing. I'll be watching with interest.
John CH
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  #3  
Old 05-08-2001, 06:15 PM
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Two quickie checks are the fuse for a/c aux. fan
and the other is jumper the high pressure sw. at the drier/reciever. If jumper works , then you more than likely are shy on freon. [ Not enough high side pressure to trip the sw., still enough to cool.] Look at eye-sight glass for low freon [ many bubbles/foam]
2nd would be the sw. itself.
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  #4  
Old 05-08-2001, 06:21 PM
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Join Date: Jun 2000
Location: Saugus, CA USA
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I've got a 190e 2.6 with the same problem and I've looked into it. The two fans are in parallel, if only one comes on, the other one is dead. Someone mentioned if you bang on the shaft it might do something. My dead fan twitches when I bang on it. As far as getting it out I was looking at just the other day and it looks like the fans are on a common mount and both need to be removed. Don't quote me on that though. As far as checking it, I unplugged the connector and hooked the battery up to it and did get the good fan to come on. Someday I'd like to bypass the power switch so the fans stay on after the engine is off so stuff under the hood doesn't cook.
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  #5  
Old 05-08-2001, 06:27 PM
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After all that work

my initial thought would be "did everything get hooked up like it should".

I currently have an issue with my E320 aux fans that I am going to start nosing around this weekend. When the fans are supposed to be running they only start if I get out and give one of them a "spin". Once they are running everything is fine and works as it should. Thanks to Authur for reminding me I have the CD I reviewed it last night and the first thing I am going to check is the "series resistor for the aux fan". The symptoms are telling me to check it first. I will keep ya'll* posted.

Jim
'85 300D - toy
'95 E320 - garage queen
'97 CRV - Wifes car

*GOB talk for everyone that is reading this
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  #6  
Old 05-08-2001, 08:38 PM
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nothing wrong with the resistor

will continue troubleshooting over the next few days. I cleaned the ends of the fuse and the fans will come on with the a/c after a brief period of time (I thought they were supposed to come on the moment the a/c button was pushed). The ambient conditions were not favorable for driving the engine temp up much today.

In the CD rom it refers to doing something called "bridging plug on coolant temp sensor or on the pressure switch for aux fan" to test the function. What exactly does this mean?

thanks
Jim
'85 300D
'95 E320
'97 CRV

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  #7  
Old 05-08-2001, 10:13 PM
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Jim,
The pressure sw. on your E320 is on the drier. There is a pair
of wires coming off it that have 2 slide-on connectors
about 4" from the switch. These will tell you if the a/c fan circuit is OK by jumping them together.
The purpode of the sw. is to put the aux fan on low speed when the a/c pressure gets high. [ usually in warmer temps]
If it is cool out , the high side pressure is not enough to trip the sw., thus no low fan. The resistor is how the fan gets it's low speed . [ if fan does not come on when hot ambiant, it is possible you are light on freon and not attaining high pressure to trip sw.]
The high speed fan is triggered by the engine coolant temp sensor. This is independant of the a/c system.
If the high fan comes on during a/c usage, it is because the a/c is indirectly puting a load on the engine and also heating the radiator to the point of tripping the engine coolant temp. [ this can be seen at the temp gage]
The point being that the a/c is merely causing the engine to heat a call for high fan.
The jumping of each switch in the manual is to test the individual circuits.
Arthur

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  #8  
Old 05-08-2001, 10:30 PM
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thanks Authur

I went out looking around some more this evening. First thing I did was replace the aux fan fuse with a new fuse with clean ends.

I unhooked the temp switch connector at the thermostat housing and both fans came on wide open. I hooked this back up and then I turned the a/c on and off and it seemed to work fine operating at low speed. May have been just the fuse not making a good connection. I will drive it sometime this week in traffic when it warms up and see if the temp switch brings it on. If it does not I will take a long hard look at the temp switch.
thanks,
Jim
'85 300D
'95 E320
'97 CRV
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  #9  
Old 05-09-2001, 10:55 AM
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Thanks for the replies! I'm even more confused now. If the fans are to come on as parallel, does that mean the driver's side fan is out? Is there a resistor or something that could be preventing it from coming on? A switch between the two? Is there any part of the fan that's replaceable without taking the whole front of the car OFF?
When I jumped the two wires with the A/C on, nothing happened. It was in the cool of the parking garage. When the car warmed the pass. side fan came on and off as it should. If I unplugged either of the wires coming out of the switch while the pass. side fan is running, it stops. Hmmm... Normally I can figure these things out. Wish I could just put the big fan from my old TD on there.
Thanks for ANY input. I'm still confused, but at least confused with somewhere to start...

Robert
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  #10  
Old 05-09-2001, 06:29 PM
someguyfromMaryland
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REmoving 300TE aux fans

While we're on the subject, has anyone removed these fans? I'd like to overhaul mine and relube the bearings (don't bother telling me their sealed, I understand sealed bearings, do you?) before they die. The fans still turn over ok but the car has 209k miles and now would be the right time. My car is a 4matic and the p/s cooler (just a tube run in front of the fans) appears to be an obstruction. Can you get the fans out without disconnecting the p/s cooler?

Let me know if you've BTDT.

Thanks,

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  #11  
Old 05-10-2001, 12:00 PM
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Had a chance to run the car last evening and watch the fans. My earlier posting was incorrect. It only runs the fans when the A/C builds up pressure, and then only one. I drove the car in stop/go traffic until the temp gage got up to 100. The fan never kicked in. I had to get on the highway drive at speed to get it to cool. Before I buy a new fan I'd like to determine what will make them come on. The sensor on top of the motor (sort of under the air cleaner housing) doesn't have a cover...just two wires attached to the sensor. Is that what is out? Or is there a relay?
I'm going out of town tomorrow and would like to fix this before leaving. I truly appreciate ANY suggestions short of a toggle switch on the dashboard.
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R Talley
88 BMW E32 735i (make it go away)
95 Volvo 960 "Inga" (valve problems)
95 Nissan Maxima (the indestructible)
89 Ford Ranger XLT (ugliest truck in the South)
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  #12  
Old 05-10-2001, 01:05 PM
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Please re-read Arthur's post

It contained *everything* that's pertinent to your problem.

Since only one fan worked, the switch is ok and a new fan is in order.

Re TEMPERATURE: although 100C is where it is designed to come on, in my car it is more like 105C. Probably the same for you. This is triggered by the Engine Coolant Temp (ECT) sensor as Arthur described. This is mounted on the front of the car near the water pump.

The sensor on the air cleaner is the Intake Air Temp (IAT) sensor. Has nothing to do with A/C or fans.

[Edited by JimF on 05-10-2001 at 07:54 PM]
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  #13  
Old 05-10-2001, 01:22 PM
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Jim,

Thanks for your reply! I am sure one of the fans is out. The sensor of which I'm speaking is UNDER the air cleaner, and screws into the head. If you jump those two wires, the fan comes on. Over the weekend, driving with the air on, the temp raced up to near 120, and when I turned the air off, the fan wasn't running even though the temp gage read that high. I let the car sit for a couple of hours (long enough to watch the movie) and cool. The temp outside was about 75, so I would like to get it fixed before temps in Texas get to 100 (about another 3 weeks). I would think that over the 100 degree mark, the fan should kick in at some point. It gets up to that point just sitting in traffic. I'm going to flush the system again this weekend to make sure no more gunk (oil) is in the system.
I would assume this sensor on the head is the same one as near the water pump on the E320.
The water pump on mine was replaced in February.
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R Talley
88 BMW E32 735i (make it go away)
95 Volvo 960 "Inga" (valve problems)
95 Nissan Maxima (the indestructible)
89 Ford Ranger XLT (ugliest truck in the South)
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  #14  
Old 05-11-2001, 01:31 PM
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Location: Dallas, Texas
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An update...
Installed a new temp sensor and resistor last night. The fan kicks in with the A/C on at about 80 degrees. After driving with the A/C on, the car got warmer, and the fan speed went from high to low.
So, I guess I hooked up a wire backward. Which wires would do this? The resistor, the temp switch, or the wires coming off the drier? After all this I know I need a fan, so I'll install this next week.
Thanks for all your help!
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R Talley
88 BMW E32 735i (make it go away)
95 Volvo 960 "Inga" (valve problems)
95 Nissan Maxima (the indestructible)
89 Ford Ranger XLT (ugliest truck in the South)
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  #15  
Old 05-11-2001, 01:53 PM
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'94 S500: only 793 sold!
 
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Confused?

Temp sensor: ECT sensor?
Resistor: looks like a coil of wire?

A/C will cause the fan to come on when a/c pressure is high independent of temperature. So that makes sense.

Confused here: "After driving with the A/C on, the car got warmer, and the fan speed went from high to low."

Low freon is the only thing that could cause that assuming that temp dial was set to LO (or cold).
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