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Radiator Fan Woes

MuffinMan7580

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Joined
Aug 6, 2011
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142
Location
Fort Bragg, NC
I have an issue with 570/1000. The PS fan is coming on whenever the battery is connected (key on or off, doesn't matter, or the storage disconnect active or inactive). The low speed circuit is utilized for the PS fan. I did not have an issue with it until I removed the fusible link box off the positive battery terminal. I moved the power seatbelts to an empty sub-fusible link spot that was unused, and the other was just a single 8 ga (ish) wire on a ring terminal going to the storage connector. The relays still function on/off as they should being triggered by the fan switch and A/C coolant temp switch. I removed EVERYTHING from the fuse box (relays, fuses and fusible links), disconnected the 2 grounds in the engine bay (2 and 4 as per the FSM), disconnected the A/C switch and temperature gauge sensor (thinking I may have mixed them up), and even tried hooking up the stock fan. The stock fan won't work on low-speed, works on high-speed, but also does not come on when only plugged in (possibly un-related?) It acts like a short, but I wanted to see if I could get some feedback on if I moved my wiring correctly, or if I'm causing a loop. The fan does not change speed when the low speed relay is energized. I checked the DS plug as well, and the same situation is occurring there as well.


The wire circled in red is of suspicion (came from the 80(?) amp fusible link slot for ABS pump


This is where I put it (I think). Now thinking back to it, I don't see why I would need it, but I also don't see it causing this issue with the fans. I've spent around 4 hours trying to diagnose this myself and now I'm reaching out for help. I have access to FSM's, but struggle to really understand the wiring diagrams (obviously).
 

GSTwithPSI

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I'm having a hard time understanding from your post what works, what doesn't, and when. There are a set of relays for each fan. Are all of these relays working?

Both fans are always supplied with 12v. To control them, the car uses a series of relays to control the path to ground for each fan. For the main cooling fan, at 185*, the thermo sensor allows a path to ground, activating the low speed relay, which then allows the fan motor a path to ground through a resistor. This gives you low fan speed. At 206*, the fan switch allows the high speed relay a path to ground, which in turn gives the fan motor a direct path to ground. This gives you high fan speed. See the diagram below, which you can pair up with the word picture above:
img.php



Your fan motor should only be able to go to ground through either the high or low speed relay. These relays should only be able to provide that path to ground if their coils are 1) supplied with voltage from the ignition switch and 2) supplied with a ground when all the conditions for activation are met (see the first paragraph). If your fan is coming on with the car off and battery connected, that means the fan motor has a short to ground. Trace the ground side of the fan motor circuit, and see where it is going to ground. If that doesn't work, connect the battery and let the fan motor run. Start disconnecting the grounds you moved/messed with until one of them turns the fan off.

Also, good reading: click
 
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MuffinMan7580

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Messages
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Location
Fort Bragg, NC
Thanks for the reply, I'll try to paint a better picture.

Relays-They function as designed, along with the fan switch and A/C engine temp switch. A/C relays are in unknown condition, but having them installed or not in the fuse box does not change the operation of the fan as of right now.

Fan-Runs when the car's battery is hooked up (regardless of key position). I have eliminated the resistor pack as I've installed aftermarket fans, and am using the low-speed circuit to power the PS fan, and the high speed circuit to power the DS fan. Fan runs at full speed, regardless of the state of the relay (open/closed).

Grounds-I disconnected both grounds the fans are going to (#2 and #4 as per the FSM, located on the DS and PS inner fender area). Low speed circuit was still a complete circuit (did not plug fan in).

Fuse Box-Fan runs even with everything removed (relays, fuses, fusible links etc...).

I double checked my radiator harnesses (DS and PS), and they're both good, I haven't crossed the ground from the fan switch to a fan or anything like that.

This problem occurred, or was atleast noticed, after I had removed the +battery terminal's 4 position fusible link box and had moved some wires (seat belts and another large gauge single white wire with a ring terminal) from there to the main fuse box. I removed the wires I had moved to the fuse box, and it did not change the situation. Before this, the fans worked as I had intended.


I'm reading that post you linked right now.
On a possibly related note, is there anything that controls the fans near the ECU. I had a friend help me pull some cable through the wiring harness grommet.
 

GSTwithPSI

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Ah, makes more sense now.

Sadly, I doubt anyone will be able to help much without seeing the car in person. You've modified the circuit(s) so that troubleshooting using the factory diagram is pretty much impossible. Not that that's a bad thing, it just that you'd have to draw out exactly how everything is currently wired (down to what wires go to what pins on the relays) before I'd be able to provide any worthwhile feedback. I bet if you did this, you'd probably solve your own problem.

Nothing on the 1G DSM/VR-4 ECU controls the fan circuit. That's only a 2G DSM thing.
 

MuffinMan7580

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Aug 6, 2011
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Fort Bragg, NC
I was afraid I'd hear an answer of that sort. Help could still be provided though, if anyone is interested in checking their fuse blocks and taking pictures of how a stock one is setup (where power is provided from and such). I was a dingus and didn't take pictures of how it was before I started.

Edit- What about around the ECU's area, but not controlled by it?
 
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GSTwithPSI

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You need pics of the back side? Also, fuse box and batt box terminal, one, or both?

Edit: I'm not aware of any wiring that would be around the ECU that would affect the fan circuitry. Off the top of my head, the only wiring that would even run inside the cabin having to do with the fan circuit would be the ignition switch wiring, which is on the opposite side of the car.
 
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toybreaker

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Apr 30, 2006
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Only thing inside the cabin that *could* be a player is the a/c compressor control box (and / or it's harness). Might be worth looking at if this happened after things were disturbed behind the glovebox.

It's a black box, about the the size of a pack of smokes, located on the hvac housing directly behind the glovebox.
 
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MuffinMan7580

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Aug 6, 2011
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142
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Fort Bragg, NC
Pictures of any/all of the bolted connections of wiring entering/exiting the fuse box, and the same type of connections of the wiring in the battery terminal fusible link box, and what they're associated with. I know it's a pain in the ass, but I'd be really grateful.

I'll double check the A/C stuff behind the glove box to rule it out, thanks!
 

MuffinMan7580

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Joined
Aug 6, 2011
Messages
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Location
Fort Bragg, NC
A little update. I went back and found all the wiring I had moved, and it all checks out. The second wire I moved was the white/black wire from the main fusible link junction to my distribution block (B+). The main fuse box is now oriented so any wiring in the back of the fuse box is not in contact with any part of the body, and I still have this fan issue. I've made some pretty knowledgeable friends this week out of happen-stance, and I'll be enlisting some of their help for a couple sets of new eyes. Hopefully I'll have an update tomorrow with some good news.

I haven't had a chance to check the A/C wiring behind the glovebox yet, but that's on the to do list tomorrow before I go and start ripping wire loom off of the harness.
 

MuffinMan7580

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Aug 6, 2011
Messages
142
Location
Fort Bragg, NC
I'm still at a loss with this. Fan is wired up to pins #3 (+) and #6 (-) as per the FSM pinout. Wiring for the fusible link box has been put back to stock, as well as the alternator wire.

HVAC control box behind the glove box-Has no effect on the fans, plugged in or not.

Managed to locate the ground wire the fans are using right now, it's at grounding point #2 on the PS inner fender. I currently have the wire unplugged from the junction and am connecting it manually to check things.

The hot side of the fan circuit seems to function as it should.

The radiator fan relays in the fuse box still are being bypassed somehow.

A relay on the DS in front of the power steering pump will click on when ground is connected, but the fan still operates when the relays are removed from the harness (FWIW, the relay with the GY wire, which I believe to be the condenser fan motor relay Lo, connector A-26).

I find it odd that even though all the grounds were removed from the chassis, the fans were able to back-feed through another ground wire. The wire i believe it to have been back fed through is the forward-most ground on #2. Does anyone have any idea what that goes to, and is my fan wiring wrong? Is there anything else that could be causing this?
 

GSTwithPSI

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The main factory fan comes wired to pins 3 (+) and 4 (-) as traced from connector A-29. If you're currently trying to mimic the stock configuration, swap your fan wires to these pins. If your fan ground wire is currently wired to pin 6, it will have a direct path to ground all the time just like you're describing. Swap the ground wire and you'll probably fix your issue.
 
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MuffinMan7580

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Aug 6, 2011
Messages
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Fort Bragg, NC
Issue resolved. I wired it up as per the other thread that was linked, and it worked as soon as I remembered to hook the grounds back up!


I feel like I should have noticed that pin 6 was grounded as much as I stared at the diagram.
 

GSTwithPSI

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Don't feel bad man, sometimes it just takes another set of eyes. After looking at that for too long, the lines start to blur together. Glad you figured it out finally!
 
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