The last radiator fan wiring thread

[broxma]

Typically I use the search ability, even throw in the "+" and whatnot but my issue with my primary cooling fan transcends any search results I found.

Everything is in reference to the 6 pin plug at the radiator, the main cooling fan and the temp sensor located on the radiator.

I have a 6 pin fan side harness. It is not from a GVR4 so the wire colors don't match. I have searched fan wiring and while the wisdom "just use these two wires for "x" and these two for "y"" makes sense, I am unable to wire my fan in properly due to the uniqueness of my specific harness, again, not from a GVR4. My fan side harness doesn't have a resistor, just 6 wires. I cannot confirm any of the wires by color except on the harness side of the plug. I have searched for a pin out of the specific plug but either cannot find it or my sleuthing skills are not up to par.

What would be most beneficial for me would be a "pin 1-6" review of the wires. The best way I think to arrange this would be to get the 1-6 pinout as if looking at the pins on the harness side plug with the release tab to the top. Something like this...

Looking at the pins, holding the wires..

(release tab)
(Pin 1 - xxx Pin 2 - xxx Pin 3 - xxx)
(Pin 4 - xxx Pin 5 - xxx Pin 6 - xxx)

I honestly don't care too much about the color, just the function in relationship to the location.

If anyone could manage such a feat I would be eternally grateful. Thank you.

/brox

 

[solidviper89]

what are you trying to do brox?

web page

 

[broxma]

that harness, but I need the location pinout as it sits in the real world. All the posts I found say, these two wires and these other two wires, but again, I don't have the fan side GVR4 harness so the wires don't cross the plug with any coherence. I need to know which two go the fan, which two to the sensor and what specific pin goes to each specific color, (Blue/Black - Fan) (Green/black - Sensor).

Again, anything from the fan side harness does me no good what so ever. I need the pin out from the harness side similar to how I arranged it in the first post. I know you can hook that up Rick because you're a smart one.

/brox

 

[solidviper89]

I could go and check stock fan? Would that help? I have an ohmmeter

 

[524of1000]

I have a wiring diagram I can bring to you tomorrow AM if you would like. Call me and let me know....

 

[broxma]

I'm out the door at 9 tomorrow. Tuesday is better since the Big H is stopping by to pick up his stuff.

/brox

 

[cspetros]

Check out the circuit diagrams located in the factory service manual for the Turbo fan harness. Actually, here it is, along with the wire color chart:

Connector A-29 is the one you're interested in. It has 6 pins. From the diagram, you can see the pin designations as follows:

Pin 1--------Blue{L}-----------------From Fan LOW relay to Resistor
Pin 2--------Green&Black{GB}---------From Fan LOW relay trigger to Thermosensor
Pin 3--------Blue&Black{LB}----------From subfuse panel to Fan
Pin 4--------Blue&White{LW}----------From Fan Relays to Fan
Pin 5--------Black{B}----------------From Thermosensor to GROUND
Pin 6--------Black{B}----------------From Resistor to GROUND

Somebody should check that over to make sure, but I'm pretty sure I read the diagram right. The sensors just control which path the fan current takes to Ground using relays. If the Thermosensor (the one in the radiator, I think) is on, the relay that routes current through the resistor (slower fan speed) is switched on. If the Engine Coolant temp. switch (the one at the thermostat housing) is on, another relay that routes directly to ground is switched on, totally bypassing the resistor (regardless of the state of the Thermosensor), resulting in a faster fan speed.

Hope this helps. /ubbthreads/images/graemlins/cool.gif

 

[broxma]

Since I would think the increase in fan speed is achieved by increasing voltage across the motor, I can understand how it works fundamentally. A given is that the low speed relay would already be active (at 85c), allowing path to ground, with an further increase in temp (to 97c), measured by the thermostat sensor which would also allow a path to ground. The low speed relay activates at 85c, stays on until it drops below that temp and the extra voltage is achieved with activation of the high speed relay at 97c. Since it is wired in an "or" configuration(Both relays share a common positive and ground in parallel) rather than an "and"(Single positive and ground in series), even if the low speed relay is not working, the high speed relay will kick on at 97c regardless of the low speed relay.

What I don't see on that diagram is the fan itself. I see how power is reduced going through the resistor after activation of the low speed relay and full voltage through the high speed, but where is the fan? It would seem that the fan would need two inputs for this to work.

/brox

 

[cspetros]

This is turning into my circuits class.... /ubbthreads/images/graemlins/wink.gif

You've got it /ubbthreads/images/graemlins/smile.gif. A voltage drop occurs across any resistor with current flowing through it, so lack of one in a circuit increases voltage across the said motor. Definitely nice to see the OR and AND analogy to this.

The key is that the fan only has 2 pins; the high pin {3} (12 volts), and the low pin {4}(The GND pin). Pin 4 can either be totally grounded (High speed), grounded with resistance (low speed), or no ground (OFF), depending on the state of the 2 sensors.
Quote:
Since it is wired in an "or" configuration(Both relays share a common positive and ground in parallel) rather than an "and"(Single positive and ground in series), even if the low speed relay is not working, the high speed relay will kick on at 97c regardless of the low speed relay.


This is correct. A semi-common issue found in these cars is a bad resistor. The result is that the fan only comes on when the condition for the high speed relay is met (97degC). Many people simply remove the resistor.

To finalize: the fan motor is across pins 3 and 4. Pin 4 can be at 1 of the 3 states listed above (High{zero resistance}, Partial{resistance}, Off{infinite resistance, or open circuit /ubbthreads/images/graemlins/hsugh.gif}).

Oh, and one important note I forgot to mention above: current always takes the path of LEAST RESISTANCE. So, even though the High speed and Low speed relays share Pin 4 of the fan (the Low speed relay will always be On when the High speed relay is On; the Low relay is On for any temps 85degC and above), the current will flow totally through the High speed relay, because it's a straight, non-resistant path to ground.....

Hope that makes sense. It's hard to pick the correct way to order all of this in writing sometimes... but it's all good /ubbthreads/images/graemlins/hsugh.gif

 

[broxma]

And since I, and everyone else, wanted this to be the ABSOLUTE DEFINITE LAST thread on this topic, we are saying, looking at the plug, holding the wires, the fan gets signal from pins 3 and 4, The sensor in the radiator from pins 2 and 5, the resistor runs between 1 and 6??

So we have no confusion what so ever.... I want to be sure, that this will be the thread we can point all future posts about this singular issue to. I am even going to make a final post with the exact pin out aside from the schematic so anyone can wire these or any other slim fans up properly and have them running properly.

I think you are getting the cut of my jib here. I don't want anything left to question.

/brox

 

[cspetros]

I see what you are trying to accomplish.

The manual defines the "Thermosensor" as the one inserted into the base of the radiator (Manual Group 14, Page 9), and the "Engine Coolant Temperature Switch" as the one inserted into the thermostat housing (Manual Group 14, Page 31)

Your summary is correct. It's important to note that Pin 4 has 2 branches, one to the low speed relay, and one to the high speed relay. But, essentially, 3 is Fan High, 4 is Fan Low....

Also, think of all the components on the A-29 connector as being on the "fan side"... this helps you get your head around how the connector is oriented. You will notice that the Fan motor, the resistor, and the radiator thermosensor, are all part of the same little harness..... this harness plugs into the main control harness (the one you're interested in getting the pinouts of) so, you'll see that:

Between pins 3 and 4 (of the fan side connector) is the fan motor. When plugged into the main control harness, Pin 3 links the fan motor to the subfuse link. Pin 4 links the fan motor to the poles of the high speed and low speed relays.

Between pins 1 and 6 (of the fan side connector) is the resistor. When plugged into the main control harness, Pin 1 links the resistor to the low speed relay pole. Pin 6 links the resistor to ground.

Between pins 2 and 5 (of the fan side connector) is the radiator Thermosensor. When plugged into the main control harness, Pin 2 links the thermosensor to the low speed relay trigger. Pin 5 links the thermosensor to Ground.

By connecting A-29 (fan side and control side) together, you're just making all of these links.

/ubbthreads/images/graemlins/smile.gif

 

[broxma]

Does that mean both branches are connected to the fan? Do you mean from the relay? This I believe is a large part of the confusion. I'm gonna pull out the MSPaint in a minute. /ubbthreads/images/graemlins/smile.gif

/brox

 

[cspetros]

Hey, I found this. This is the little harness I mentioned, containing the fan motor, the resistor, and the thermosensor.


This connector connects to the main control harness, joining these three items to where I mentioned above. I guess I'll wait till you use MSPaint...

I'm going to sleep now... can't think much more /ubbthreads/images/graemlins/hsugh.gif. g'Nite.

 

[524of1000]

Thats the exact stuff I was gonna bring you lol

 

[broxma]

So tonight I got the bug to figure the entire thing out. I have been able to get the fan working by grounding out the sensor plug. I learned one thing in the process. Onto the definitive answer.

The image of the clip from the schematic above is from the HARNESS SIDE.

 

[solidviper89]

Good info! This should be stickied? /ubbthreads/images/graemlins/laugh.gif

 

[broxma]

It may also be wrong. I realized that while the lowspeed relay is tripped by the sensor activation, the fan doesn't come on. I can manually trip the relay by looping the sensor plug but with the fan connected at pins 1 and 6, nothing. I verified that the fan has a good connection going through the fan side harness plug by running wires to the pins (1 and 6) with some wire. Fan comes on. So i know it's not a physical issue with the wires or the fan. It must again be the wiring.

So I pulled every wire from the harness side out and looped the 5-2 pins which did in fact trip the relay. One would assume then that at least one of the other 4 wires would have power. No. Nothing. I was unable to find power at any of the 4 wires. I have since maintained the relay switch active, and swapped every wire with every other(Loop the resistor) and checked for 12v on the other two. Under no circumstance could I find 12v regardless of configuration. This tells me two things. One, it may be a physical issue beyond the scope of the harness and two, it is a ton easier to just wire the stupid fan up to a relay and install a switch which is what I am doing now.

If anyone else wants to run with this, feel free. My conclusion to this post is,it is easier to install the fan on a relay and a switch than spend hours dealing with the futility of hunting this stupid electrical gremlin.

/brox

 

[Lucas03ES]

Okay first I know this is a bit of a bump, I have already messaged brox and he said he never got it figured out, and I didn't want to make another thread on this subject. I'm essentially doing the same thing here and was wondering if I could get some help to see if I could get it to run off the stock circuit before running a manual switch. I am going to be installing a dsm 4-pin radiator fan harness, instead of the gvr4 6-pin. The only difference I see between the two is that the dsm did not have a resistor stock. Correct me if I am wrong, please.

Pins 2&5 to radiator thermosensor (order not important)
Pin 3 to SPAL fan (+)
Pin 4 to SPAL fan (-)

Now my question is what should I do with the 1 and 6 pins, should I just splice them together so the fan will always trip in to the stock "high" mode? or should I add a resistor to the circuit?

Also, is it possible to test this without heating the car up all the way? As, it is a new motor that has not been fired on yet.
Thanks!

 

[MuffinMan7580]

Quoting broxma:
So tonight I got the bug to figure the entire thing out. I have been able to get the fan working by grounding out the sensor plug. I learned one thing in the process. Onto the definitive answer.

The image of the clip from the schematic above is from the HARNESS SIDE.

 

[Terrance362]

I second that. works like a charm