Joel's_84_944

Hey everyone,

I am having a overheating problem. I replaced the ThermoSwitch, Thermostat, and the Cap for the resevoir. I pressurized the coolant using the instructions from Clarks-Garage.
But when i turn on the Car, and let it warm up, The drivers side fan never turns on to cool down the car, the Passenger fan turns on. When i turn on the A/C only the passenger fan stays on. I cannot get the drivers side fan to turn on. I checked the fuse and it was blown. Replaced it but still the DS fan will not go on. What steps should i take to check the fan?. I am at a loss, I 'don't know what to do.. Is it the fan itself or just the motor, connections.......

I need some help since I have to get this running before monday, I have to work the late shift again, and I don't want my wife and kids to have to pick me up @ 10pm, when they get up around 5am everyday.

thanks.....

Granite 944

Sounds like a bad fan motor to me. But, you could try switching the wire connectors that go into the motor on the passenger side with that of the other, and you'll have a good idea if its the motor or wiring. Turn on the AC button, if that drivers side motor still won't come on, its the motor (look at that drivers side connector real good however). Both motors run at the same time on the earlies. Different on the laters. HTH

hosrom_951

How about the actual fan connection to the harness? it looks like a plug, maybe it's loose or has some corrosion there.

Did you try the trouble shooter at clarks?:http://www.clarks-garage.com/shop-manual/cool-01.htm

lleroyb

Charlotte944 posted this a couple of days ago.

"Lou:

Here are the differences:

On the early cars, only ONE fan is "dual speed" This is the driver side fan. The only time this fan runs in slow speed is when the ignition is OFF and the radiator is "hot". When the ignition is on and either the radiator temp switch is closed, or the A/C is on, BOTH fans run at high speed. The slow speed control is provided by a current limiting resistor that is in series with the temp switch and the fan. When the ignition is on and the radiator is hot, the cooling fan relay shorts out the resistor so the fans run at high speed. When the A/C is on, the A/C relay shorts out the radiator temp switch so both fans run continuously at high speed. The radiator temp switch has one set point, and is either open (fans off), or closed (fans on).

The later cars are a tad more "sophisticated".

First off, the radiator temp switch has TWO set points, and fan speed is controlled by the fan relay, G19. When the lower set point is reached, G19 runs both fans in slow speed. When the upper set point is reached, both fans run at high speed. When the ignition is off and the radiator is hot, G19 runs both fans in slow speed.

Second, G19 also gets two inputs from the A/C system. When the A/C is on G19 runs the fans in slow speed (Normal operation). The second input comes from a "Refrigerant Temperature Switch" which is located at the reciever dryer. This switch actually senses refrigerant pressure, which is a function of temperature. If you look at the A/C plumbing at the reciever/dryer you can see two switches. The upper switch with the green top is the temperature switch. The other switch is the A/C low pressure shut down.

Anyway, if you trace the wires from the temp switch you will find two male/female connectors. These wires are in parallel with the high temp setting input from the radiator temp switch to G19, so when the A/C temp switch closes, its just like the radiator upper temp set point was reached. this additional switch is necessary to protect the A/C system from over pressure during idle conditions, or when you are sitting in stop and go traffic. Early cars do not need this switch because the fans are running at high speed whenever the A/C is on.

Hope this helps."

I like the idea of swapping fan connectors if they reach. If that does not move the problem I would try a different fan relay.

Lou

xsboost90

pull the plug nearest the fan, w/ the a/c etc turned on..check for 12v power...if none, its a relay or something. If it has power, the motor is most likely toast. If your brave, try to put 12v to the motor to jump it...but carefully.

Bret 944

We just wired our fans to a switch in the car on our '84. Couldn't get them to work right. Now they come on when I say so !!

Joel's_84_944

Well,

I swapped the connectors from the PS fan to the DS fan, and it turns on.. I used the jump wire on the thermoswitch (which is brand new I might add) and neither one turns on. I Turn on the A/C and only the PS fan kicks in. I have family over (great timing guys)
so I will have to check the other steps you guys just mentioned when I get back from work.

thanks......Joel

P.S. BTW where is the fan relay anyway?

KuHL 951

Joel,
If you need a pair of fans and shroud I have the good ones off my 83 when I did the 6-blade upgrade. Yours for the cost of shipping.
Steve

Granite 944

Well, its not the fan motor itself then. Kinda sounds like the relay might be bad? See http://www.clarks-garage.com/shop-manual/cool-01.htm for fan troubleshooting procedure/operation.

The cooling fan relay is in the relay box in the #1 position. Uppermost/ leftmost relay. Fuse for it I believe is # 5 in aux. fuse box. IIRC, its easier to access these upper relays in the relay box if you first drop the aux. box loose. Make sure your fan connectors are not cruded up and making good contact. Clean and dielectric grease. Good luck

Joel's_84_944

hey,

I pulled out the relay and tested the resistance and found out the relay is bad. So when I went to check online for a replacement, @ 944online and Eurowebparts.com has the 6 prong relay for an A/C relay. My relay shows part # 898340, so does the pics online. But on Vertexauto.com it is showing a 4 prong Relay showing part # 431.951.253 H. I can't seem to find the one I need .

Is it supposed to be a 6 prong relay or a 4 prong relay?

HEELLLLLLPPPPPPPPPPP!!!!

Granite 944

My Parts and Technical Reference Catalog shows that in the #1 position, relay should be pn 141.951.253B (4 prong FAN RELAY). In position #3 on the board, it should be pn 944.615.113.01 (6 prong A/C RELAY) which also has the 898340 on it.

Both of my cars use the 6 prong/944.615.113.01/898340 relay in the #1 position. So if yours is the same, you need this 6 prong relay.

I'm a little confused with what is really what here according to the books, but go with the same as you had. It will be one of the two numbers above. It was working properly until recently, right? According to Clark's test procedure, your testing a 6 prong, when testing the fan relay, so thats what I would deduct from this.

Joel's_84_944

Ok,

It took over a week just to get the part, but I won't get into that.

I replaced the faulty relay with the new one, started her up, everything seems fine. I turned on the A/C and both fans are turning. I get up this morning and get ready for work, started driving and got to the I-275 and when I am on it The needle goes past the middle mark! I'm like what the H...! . So I turn on the A/C and it keeps it on the middle mark. At lunchtime I'll check the fluid level and add some if it needs it. When I get home I'll try and pressurize the coolant again. But If that is not it, then what else is there?. BTW the thermostat I bought is the 72 degree one, so Technically the DS Fan is supposed to turn on earlier right?

I hope to GOD the Father it's not the Waterpump, If it is.....that's it I'm done.

Granite 944

Sounds like the fans are both working fine. At least when you use the AC switch. Both fans will run on this car only when the temp. switch in the radiator tells it to. Both fans work together on these early cars, not independantly. Both fans will run in a slow mode, after the ignition switch is off, and only if the temp. in the radiator tells it to. Clark's Garage for more info.
You say the needle goes past the middle mark. Do the fans come on automatically at any point when this happens? If your car is trully overheating, they will (or should). If they are not coming on, might be the gage itself. I'd be a lot more likely to believe that there is a grounding or bad connection problem at the temp gage sender on the engine or possibly other grounding issues like the main ground at the back of the engine. I've had that experience with the gage reading higher than it should (but the engine was not overheating, it was a bad connection at that sender unit). I also cleaned my rear engine grounds, and added a #4 wire (battery cable basicly) from the upper balance shaft bolt to the drivers side headlight lamp area frame grounding point. All of these actions made a sizeable difference in how the gage itself operated. Also make sure your bleeding the air out of the system real good. If none of this works, then I'd start thinking plugged radiator, or yep, maybe the waterpump. Good luck!

EDIT: Above I said "Both fans will run in a slow mode, after the ignition switch is off,......." . It should be drivers side fan only.......
Thats the only time only one fan will come on by itself.

PaulStewart

Have you bled the cooling system?

Any chance your timing belt is loose and not turning the pump?

Jon Moeller

Joel,
What's your voltage gauge indicate?
FYI, the lower and upper lines cover a range of ~10 degrees, so it's not too big of a deal if you're running a little hotter. Once you pass the top white line, all bets are off.
I ask about your voltage gauge as the ground issues in these cars can result in skewed results from the electrical gauges.
-Jon