View previous topic :: View next topic |
Author |
Message |
bufflars12
Joined: 22 Apr 2006 Posts: 21 Location: ny, 10923
|
Posted: Thu Apr 27, 2006 11:34 am Post subject: cooling fan problem |
|
|
i am having problems with my cooling fans..if i were to hard wire them on with a switch, would the engine run too cold? can i just turn the fan on when the temp gauge gerts past the cent line. if this would be a good idea how would i go about doing this. where should i cut the fan off and wire the switch from? should ibypass the thermostat? any help would be apprecaited.thanks |
|
Back to top |
|
|
gohim
Joined: 02 Nov 2002 Posts: 4459 Location: Rialto, CA
|
Posted: Thu Apr 27, 2006 12:01 pm Post subject: |
|
|
It would help if you posted what model year your car was, and whether it has ac or not.
It would be easier if you fixed your problem with the factory fan wiring then if you were to hack the wiring, and try to remeber to turn the cooling fans on or off at the right time, so you don't overheat and damge the engine.
What exactly is your problem with the cooling fans? |
|
Back to top |
|
|
bufflars12
Joined: 22 Apr 2006 Posts: 21 Location: ny, 10923
|
Posted: Thu Apr 27, 2006 12:03 pm Post subject: |
|
|
its an 84 944 with a/c. it seems that the drive fan doesnt kick on. could it just be the thermostat? |
|
Back to top |
|
|
Lizard
Joined: 03 Nov 2002 Posts: 9364 Location: Abbotsford BC. Canada
|
Posted: Thu Apr 27, 2006 12:24 pm Post subject: |
|
|
running the fans constant will not cause the engine to run too cold, but it would be a waste of energy,
as per the fan first verify that with the ign on you are getting a + 12 volts to one of the connectors for the fan. you then need to find the temp sensor in the rad and pull the connectors off it and bridge them together and see if the fan runs,
the two options if the fan doesnt come on when running but by bridging the wires it does is #1 temp switch in rad is cooked, #2 is rad is not opening to allow enough fluid through. _________________ 3 928s, |
|
Back to top |
|
|
gohim
Joined: 02 Nov 2002 Posts: 4459 Location: Rialto, CA
|
Posted: Thu Apr 27, 2006 12:50 pm Post subject: |
|
|
The cooling fans should go on whenever the temperature designated by the cooling fan switch (located in the radiator) is reached, and cut-off when the coolant temperature drops down to designated temper (7-10 degrees lower than the "turn on" temperature).
If the temperature switch in the radiator is defective, the fans could be on all the time, or never go one. There are also two relays that affect the operation of the cooling fans. One is the cooling fan relay, and the other is the ac relay. When the ac is turned on, then the cooling fans will continue to run, regardless of the temperature.
If either of the relays is defective, the cooling fans may not function, or may be stuck on.
On a 84 944, you should have a cooling fan relay with two wires on it. Short the two wires together with a sturdy screwdrivers with the ignition off, and the fans should both run at the low speed. If you short the two wires together with the ignition on, then the fans should run at the high speed.
If the cooling fans will not activate with the ignition on or off, with the wires shorted, then you probably have a blown fuse or bad wiring. If the fans will run at the low speed with the ignition off, but not with the ignition on, then the cooling fan relay is probably bad. If the cooling fans will run at the high speed with the ignition on and the ac on, but will not run with the ignition on and the radiator (thermofan) switch shorted, then the cooling fan relay is probably defective. If the cooling fans run at the low speed with the ignition on, the ac off, anf the radiator switch shorted, then the cooling fan relay is probably defective. If the cooling fans will run at high speed with the radiator switch shorted, and the ignition on, and when the ignition is on, and the ac is on, but will not run at low speed with the radiator switch shorted, and the ignition off, then the round resistor located behind the dashboard on the driver's (left) side is probably defective (or the wiring to it is defective).
Note, depending on which fan switch you have, the fans could be switched on anywhere between 160 F and 200 F during normal operation.
Last edited by gohim on Thu Apr 27, 2006 12:53 pm; edited 1 time in total |
|
Back to top |
|
|
bufflars12
Joined: 22 Apr 2006 Posts: 21 Location: ny, 10923
|
Posted: Thu Apr 27, 2006 12:51 pm Post subject: |
|
|
thanks man. i will try this tomorrw and see how it goes |
|
Back to top |
|
|
Stampedetrail
Joined: 29 May 2005 Posts: 274 Location: Fairbanks, Alaska
|
Posted: Thu Apr 27, 2006 5:53 pm Post subject: Re: cooling fan problem |
|
|
bufflars12 wrote: | i am having problems with my cooling fans..if i were to hard wire them on with a switch, would the engine run too cold? can i just turn the fan on when the temp gauge gerts past the cent line. if this would be a good idea how would i go about doing this. where should i cut the fan off and wire the switch from? should ibypass the thermostat? any help would be apprecaited.thanks |
When my temp sensor lead broke off, I connected the two leads together that otherwise go to the temp switch (at the radiator, on the driver's side), because I wasn't sure if the temp switch worked or not. The fans ran all the time when the ign switch was on. It doesn't change the temperature of the engine at all, since its temp is controlled with the thermostat. It was just a safety precaution. When I fixed the temp sensor lead, I reconnected the temp switch. If you're iffy about your temp switch, by all means hotwire your fan by connecting the two leads together until you can test your temp switch.
Test the temp switch with a multimeter & with the temp switch sitting in a pot of boiling water & a meat thermometer. |
|
Back to top |
|
|
gohim
Joined: 02 Nov 2002 Posts: 4459 Location: Rialto, CA
|
Posted: Thu Apr 27, 2006 11:36 pm Post subject: |
|
|
Making a fixed connection between the two leads that are normally attached to the thermofan switch is a BAD IDEA. Yeah, the cooling fans will run alright. They will run whether the ignition is on or not (at high speed when the ignition is on and at low speed when the ignition is off). The only time that the fans would not be running is if the low speed sooling fan resistor is disconnected, or burned-out, or if the battery is FLAT.
The thermostat controls whether coolant flows through the engine. The thermofan switch controls whether the radiator gets the additional cooling air flowing through the radiator. You better believe that the cooling fans will affect the temperature of the coolant. Without proper operation of the cooling fans your engine is going to overheat whether the thermostat works or not.
Last edited by gohim on Sat Apr 29, 2006 5:03 am; edited 1 time in total |
|
Back to top |
|
|
bufflars12
Joined: 22 Apr 2006 Posts: 21 Location: ny, 10923
|
Posted: Thu Apr 27, 2006 11:44 pm Post subject: |
|
|
ok the a/c fan goes on when then a/c is turned on. i have yet to see the driver side fan kick on (but havent really been driving it). i am going to check the relay today |
|
Back to top |
|
|
Ozzie
Joined: 12 Mar 2005 Posts: 4448 Location: Townsville, Qld. Australia
|
Posted: Fri Apr 28, 2006 4:27 pm Post subject: |
|
|
bufflars12 wrote: | ok the a/c fan goes on when then a/c is turned on. i have yet to see the driver side fan kick on (but havent really been driving it). i am going to check the relay today |
The ac fan is operating normally.
If you join the two wires on the radiator temp switch the other fan should kick on slowly.
Turn the key on and it should run at full speed.
Let us know the results.
If the fan doesn't work at all hook up 12v directly to it and see if it runs. _________________ Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance |
|
Back to top |
|
|
Stampedetrail
Joined: 29 May 2005 Posts: 274 Location: Fairbanks, Alaska
|
Posted: Fri Apr 28, 2006 6:09 pm Post subject: |
|
|
gohim wrote: | Making a fixed connection between the two leads that are normally attached to the thermofan switch is a BAD IDEA. Yeah, the cooling fans will run alright. They will run whether the ignition is on or not (at high speed when the ignition is on and at low speed when the ignition is off). The only time that the fans would not be running is if the low speed sooling fan resistor is disconnected, or burned-out, or if the battery is FLAT. |
Not so on mine, for whatever reason, they only ran when ignition was on. You could of course wire from accessories lead if you had to. Until you get another thermofan switch. Just a thought. |
|
Back to top |
|
|
Ozzie
Joined: 12 Mar 2005 Posts: 4448 Location: Townsville, Qld. Australia
|
Posted: Fri Apr 28, 2006 11:22 pm Post subject: |
|
|
Stampedetrail wrote: |
Not so on mine, for whatever reason, they only ran when ignition was on. You could of course wire from accessories lead if you had to. |
My fan used to come on only with the key and on full.
The PO had bypassed the thermo switch and cut the wire to the resistor. _________________ Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance |
|
Back to top |
|
|
bufflars12
Joined: 22 Apr 2006 Posts: 21 Location: ny, 10923
|
Posted: Fri Apr 28, 2006 11:31 pm Post subject: fans` |
|
|
i took the fans out on wendsay and tested both. one ran 100% but the other one was alittle stiff. i broke it loose and they both spin freely when connected to an external 12v source. so its not the fan motors. i am going to connoct the two wires at the switch today and see what happens. thansk guys |
|
Back to top |
|
|
gohim
Joined: 02 Nov 2002 Posts: 4459 Location: Rialto, CA
|
Posted: Sat Apr 29, 2006 4:59 am Post subject: |
|
|
Both cooling fans should run when the ac is turned on and the ignition is on (not just the secondary cooling fan). I suspect that you have at least (1) bad relay. |
|
Back to top |
|
|
D Hook
Joined: 02 Nov 2002 Posts: 3156 Location: Omaha, NE
|
|
Back to top |
|
|
|