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post #1 of (permalink) Old 03-19-2017, 05:59 PM Thread Starter
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fan relays

Does anyone know where the power to the fan relays comes from? Does it come directly from the fan 30 amp fuses? I read that the pcm supplies a ground to turn the relays on when the engine reaches a certain temperature which in turn, turns the fans on. If the fans are turned on by the pcm supplying a ground shouldn't I have power at the relays at all times?
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post #2 of (permalink) Old 03-19-2017, 06:50 PM
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Can't remember what year car you have sorry. So on the 08 Car there are 2 Fan Fuses and where it may confuse someone. They are numbered odd..

Fan1 fuse goes to fan1 realy Fan 2 fuse goes to Fan Relay 3 and for Fan 2 Relay it is a Speed Relay that is connected between the Fan motors and Relay and some Diodes on both sides. There are 2 spots from the ECM that is part of the Source for the relay coils ground side and Emmissions 2 fuse is the hot side of the coils

James

Edit: Sorry that info was off an 09 not an 08 as I stated before even though it could be the same..

It isn't what you Drive that matters, It is how you drive it.

James

Last edited by Revo2Maxx2016; 03-19-2017 at 06:57 PM. Reason: added info
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post #3 of (permalink) Old 03-19-2017, 08:27 PM Thread Starter
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Thanks James, My car is a 09 but should be the same as a 08 I imagine. Should the 3 fan relays have 1 wire that goes to each relay that is hot at all times? I have power at both fan fuses but no power at any of the relays even when the engine is hot enough that the fans should be on.
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post #4 of (permalink) Old 03-20-2017, 12:06 AM
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Ok almost sounds like the issue again with the Fuse box that had the no start issue. Bad spot in the box it self...

However here is something to look at. Here is one of these times that it don't matter what side the Power for the Control side is on. I say this because so many people get all bent out of shape when you say 12v+ on pin 85... Anyway sorry getting off topic..

On Relay for Fan1 Pins 86 and 30 should both show 12V+ or if you test with Test light should light Red for 12v or turn light on.
On Relay for Fan3 Pins 85 and 87 should both show 12V+ " "

This again is one of them times that it can be confusing unless there is a road map for the setup.

These next test are going to be done without the Relay or Fuse installed.

So if you were to test your continuity between Fan 3 Relay Pin 87 and the bottom pin of the Fan2 fuse it should beep if you using the sound or test there is connection.

So for Fan 1 Relay Pin 30 to the Top of Fan1 Fuse and it should show connection. Another spot where there is no constant to the way people think things are or should be wired. Because the bottom of the fuse for Fan 1 is the 12V+

Problem is on most of these Fuse boxes when the top side of the block most times top of the fuse would show hot. However about middle of the fuse box this changes to the bottom of the fuses lol. There really isnt a normal anymore.

Hope this added some insight to things to check

James

It isn't what you Drive that matters, It is how you drive it.

James

Last edited by Revo2Maxx2016; 03-20-2017 at 12:16 AM.
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post #5 of (permalink) Old 03-20-2017, 03:59 AM Thread Starter
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Thank You James, It will be this afternoon before I get a chance to check but will post the results when I do. Thanks again for the help.
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post #6 of (permalink) Old 03-20-2017, 09:52 AM
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Subscribing to the thread.

Until fan starts, both coil side terminals of all 3 relays must be hot. Really strange.
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post #7 of (permalink) Old 03-21-2017, 01:45 PM Thread Starter
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James, Sorry for the delay but I had to buy a multimeter to do the test. With all fuses and relays removed I have continuity between the bottom pin of fan fuse 2 and pin 87 on fan 3 relay. Also have continuity between the top pin of fan 1 fuse and fan 1 relay pin 30. However with fan fuses installed and all relays removed on fan 1 relay I have 12v at pin 30 but 0v at pin 86. Likewise on fan 3 relay I have 12v at pin 87 and 0v at pin 85.
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post #8 of (permalink) Old 03-21-2017, 05:08 PM
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OK you need o check the Power train Relay that goes to the Emmissions Fuse 2 It is a 15amp fuse. It is controled By the relay and I need to look deeper myself see if it is constant or Controlled by Relay. I am going to assume by relay. Maybe turn on AC and see if it provides the 12v on that area!

James

Edit: Ok looking over that Relay I can find info for turning on AC should power up the Relay that would send power to the Coil side of the fan Relay that you said was showing 0V. That part is controlled by the ECM

It isn't what you Drive that matters, It is how you drive it.

James

Last edited by Revo2Maxx2016; 03-21-2017 at 05:13 PM. Reason: Added info
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post #9 of (permalink) Old 03-21-2017, 06:39 PM Thread Starter
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I will check the relay in the morning and report back. The a/c does not work. When I push the button it flashes a couple of times and the light goes off.
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post #10 of (permalink) Old 03-21-2017, 07:50 PM
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Pls delete this post
Attachment didn't upload right.

Last edited by paker; 03-21-2017 at 07:59 PM.
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post #11 of (permalink) Old 03-21-2017, 07:58 PM
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Here is 08 AC wiring diagram.
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post #12 of (permalink) Old 03-22-2017, 12:16 AM
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OK so to look over some more Relay info lol

Sadly the diagram above don't show the info about turning on the fans. That is because the Power Train Relay is still above that diagram.

So when you can. Take out the Power train Relay it will be next to the Fuel pump relay. Test Pins 30 and 85 These both need to show 12v+ at all times. IF that shows 12v on both

Remove the Emission Fuse 2 It is the fuse right next to the Wiper Relay. These tests will be with Relay and Fuses out. Test the pin closest to the Emission Relay to pin 87 of the relay for BEEP. When I say beep I am talking about Continuity. Easier to say beep lol... IF that does

You know I started to just say test this and there and so on. Forget it to much LOL . So I will post a picture of the fuse box that I drawn. Or is that Drew? I don't know but here is what I did. I added some colors to show points to test. Then they started to look the same so I added some lines to show the tests areas lol Sorry I tried lol

So to understand that Fuse Fan2 to Relay Fan 3 there is only 1 connection point there at the top of Fan 3 Relay that would beep the same area on fan 2 Relay. The rest I think you can make out. IF not Fan 3 top right to fan 2 top center. Then Bottom right fan 3 to bottom right fan2 relays also top left of Fan 1 Relay and that would go to the Emission Fuse. So them points should all test out or beep. Say starting at the Fuse, touching each spot on that pink layout should all beep.

Hope I was able to do it in a way that was understandable. I almost lost myself when I was tying this all out lol So I made this in hopes to be clear...



James

It isn't what you Drive that matters, It is how you drive it.

James
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post #13 of (permalink) Old 03-22-2017, 06:29 AM Thread Starter
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Got it. Will do these test today and get back with you. Thank You very much for your help.
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post #14 of (permalink) Old 03-22-2017, 11:59 AM Thread Starter
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OK, Just finished the test. I have 12 volts at both pins 30 and 85 at the power train relay. All the test for continuity tested positive. This is really baffling. Could the engine temperature sensor have anything to do with it? If so how could I test it? Thanks
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post #15 of (permalink) Old 03-22-2017, 12:38 PM
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There is where a Tech II would be handy lol.. There are some other tools out there that may work to test sensors. However if your not with one. You could test for 5v to the sensor and ground on the other side. I am not sure I haven't worked on one for long time. If 2 prong it would be ground for one and 5v for other. Then the Sensor would test our around 2 or 3k Ohms cold and when car heats up it lowers the reading. This changes the Info from the 5v because it is going to the computer and it reads the difference.

Is it that your fans not coming on? Could it be that your Temp isn't high enough to make the fan come on? Thermostat locked in the open state? Have you tried to command your fans on by jumping power? I don't want to say you have bad fans but that could be an issue as well...

James

are you getting any MIL/CEL on the Coolant line area If there was a problem it should trip a Code?

It isn't what you Drive that matters, It is how you drive it.

James
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