5.0stang

iTrader: (1)

I sure will - I'm going to have my mechanic take a stab at it early next week to see what he can come up with. I want to get that fixed first, before I look at the transmission purchase to hard.

Sint3k

First we will focus on the low speed circuit.

We need to find relay 1 for the fans and we need to jump it.

Remove Fan relay 1, and look for the diagram on it. Terminal 87 and 30 are the, "load side".

Remove the relay, take a jumper wire and jump those 2 terminals together, This will energize both fans on, "low".

Another method is, you can remove the top off of the relay and there is a lever in there you can manually accuate by pressing on it. Some are easy and its on the side, some are not and its on the bottom, if you have one that is on the bottom, you wont be able to manually accuate it after removing the cover, so might just be best to stick with a jumper wire.

So again, to re-iterate, Connect terminals 87 and 30 together (FROM FAN RELAY 1)with a decently heavy gauged wire and see if BOTH fans turn on. Side note, look at the relay, that is how far and the shape of the terminal it accepts, don't shove anything that is going to bend the prongs in your fuse box. You really need, "front probe jumper wire", i'm sure you can come up with something.

Let me know how it goes.

5.0stang

iTrader: (1)

I took some old "alligator clips" and stripped off the ends. I used that wire on the 87 & 30 terminals and only the driver side fan kicked on (with key on).

Sint3k

Ok, next we are going to work with only relay 2 and 3, it does not matter if fan relay 1 is pluged in or not.

Unfortunatly, you are going to need 2 jumper wires this time.

This is important you do it in this order .

On Fan Relay 2, it will be a little different. You still need to jump 87 and 30 together. Becarefull not to confuse 87A, with 87. So to reiterate, jump 87 and 30 together on Fan Relay 2.

Then, on Fan relay 3, Jump 87 and 30 together, this should make the, "passenger" fan run on high. Let me know how it goes.

5.0stang

iTrader: (1)

Well I tried it, but after rereading this I don't think I did it in the right order.

I put the wire on Relay Fan 3 first, then jumped to Fan Relay 2. Nothing happened...

I originally tried to do Fan Relay 2 first, but it was sparking (wire got hot in my hands).

Sint3k

That should not of happened, unless you jumped the wrong pins for relay 2.

But the fact nothing happened when you jumped relay 3 indicates a wiring issue or bad fan on the passenger side. I only had you jump relay2, to protect Fan 1 incase it was shorted to ground (unlikely), Engaging relay 3 should of made the passenger fan turn to high speed. SO,

That tells me you have a bad fan, or no power orrrr no ground.

So now we'll just focus on relay 3

As i said earlier, 87 and 30 are the LOAD side of the circuit, this is what powers the fuse box, when they are connected, the passenger fan should run on high.

So we need to confirm we are getting power to that relay for the passenger fan. Now depending on how you insert the relay, pin 87 and 30 can flip flop (Which does not matter) So what you need now is a multimeter.

Set your multimeter to show voltage, connect the black lead to battery ground. With the red lead, put it in pin 87 and see if you get 12 volts, if you don't put the red lead into terminal and see if you get 12 volts.

After this its going to start to get more complicated and we'll start to find ground wires etc, but this is the correct way to go about it instead of replacing parts.

Earlier in this thread you said you where able to power the passenger fan manually and it turned on, are you sure it ran ? lol. I don't want to be on a wild goose chase for a passenger fan that just does not work.

P.S. make 1000% sure your only on the 87 and 30 sides of the relay, It can get confusing when looking at it upside down etc.

5.0stang

iTrader: (1)

Yeah, I was able to kick on the passenger fan when I connected it right to the battery using alligator ciips. It is at the shop now and he is going to look at it as well. Thanks for the help so far!

Sint3k

Ok interested to hear what he says
Curious if it matches up with what we have learned so far

Thx

5.0stang

iTrader: (1)

He fixed the fan; wiring issue under one of the relay terminals that was dead. Back in action!

5.0stang

iTrader: (1)

Everything was going good, but I did recently notice that the car is running warm again in stop and go traffic.

Basically what it comes down too...

If I have the a/c on, the car seems to run cooler as it appears to cycle the fans on high, then return to low.
If I have the a/c off, the car seems to run warmer (above the middle line) and I never hear the high fans kick on. In fact, most of the time the fans don't come on at all unless it gets "hot".

When they do come on, both fans come on. If I unplug the coolant temp sensor, both fans come on high. I have put in a new AC Delco coolant sensor and radiator cap.

The mechanic suggested I may need to get a new engine wiring harness.

What is an easy way to monitor the actual engine coolant temp?

lVloses

iTrader: (1)

Easiest and cheapest way is probably a smart phone with an OBD2 app that can scan realtime and an OBD2 dongle.

rottonj

iTrader: (4)

What are you considering warm?

5.0stang

iTrader: (1)

The problem is, I don't know. Where can I get a digital read out?

What I can tell you is when the fans/car is working properly, the gauge stays in between the 2nd/3rd marker whether cruising or in stop and go.

Now, when it is in stop and go, it goes on the lower side of the 3rd/4th market (a little above the middle), but when cruising sits in the between the 2nd/3rd marker. Apparently the fans kick on when it gets between the 3rd and 4th marker and it will drop quite a bit, then come back up again and the cycle repeats until I can get on a highway.

I have never seen a car post 1995 with a properly working fan/coolant system that fluctuates like this. I want the temp to stay consistent, like 99% of cars do. This one does not.

rottonj

iTrader: (4)

I purchased this a few years ago, it works decent.

https://www.amazon.com/Vgate-Bluetoo...rds=vgate+scan

If you have an Android phone check out the app Torque pro, paired they seem to work well and will give you your temps. My GXP really never gets above the half mark unless sitting in traffic for long periods of time. Half I think we figured was about 210 degrees, and normal for most all of these cars.

rottonj

iTrader: (4)

Also if you coolant has not been flushed now would be a good time to address that, as well as the thermostat which is no fun at all(search my post on that if you want). You could have some air in the system.

5.0stang

iTrader: (1)

I have a Diablosport - I wonder if I can do something with it or play with the fan "turn on" temp.

There is coolant in the overflow reservoir and when I take off the cap, there is coolant at the cap height so I believe my level is fine.

I have an Iphone.

I wonder if when the temp gets over halfway, that is around 220* and the fan kicks on and it drops the temp:

The PCM commands High Speed Fans on under the following conditions:

• Engine coolant temperature exceeds approximately 105°C (221°F)

I also have a 2005 LS Suburban and the temp gauge never moves once it reaches operating temp, no matter what conditions I put it through. None of my other cars have fluctuated either like this one does.

rottonj

iTrader: (4)

My gauge gets under half and doesn't move. They most likely have the app for Iphone too, if you go that
route. I know nothing of Diablosport , or any tuning devices really.

Edit: guess no Torque for Iphone

lVloses

iTrader: (1)

Post up a picture of your coolant gauge and where it's at that you're concerned about.

Here's the fan settings for an 08 GXP:

cheeseburger03

Sint3k,

hate to wake an old thread, but I'm having a similar issue, but in my case only passenger fan kicks on and off when temp gauge is between the 3rd and 4th marker. I also think this fan issue is affecting my AC as well, cause only when it's real hot, the compressor disengaged, typically at idle, but as soon as I drive off, it reengages.

can u help me?