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Engine overheating due to fan not working


jerryhunt92284
07-07-2011, 11:34 PM
1999 Pontiac Grand Am SE, V6.

At first my reservoir cracked so I replaced it. I guess the fans might have had enough because one of them quit. I have realized that this is the fan related to the engine (or radiator?) because when I turn the A/C off, the other fan quits going and when I turn the A/C on...the fan on that side still works. The fan that doesn't work is on the left (driver) side.

I tested all the fuses and they are good. I am still confused on how to test relays, but I just pulled relays that I know worked and swapped them out with the coolant fan and it still did not come on. The wires going to the coolant fan were electrical taped so I removed the tape, re-wired it and put tape back on. So, I guess all that is left is the coolant sensor and the fan motor? The coolant sensor looks super easy to replace so it looks like I will do so tomorrow. But are there any other ideas?

Also, there seems to be this elusive fuse, #55. It says Coolant fan #2 ground (30A), but when I looked in the fuse box, there's not a retainer (right word?) for the fuse. Meaning, when I put the fuse in, it just wobbles back and forth unlike other fuse ports in which you put a fuse and the fuse gets held in place pretty firmly. You can see that there's metal prongs in the port to provide connectivity, but this is not the case for #55.

Thanks in advance for the help.

Edit: the obd II reader pulls no codes at all.

enslow
07-08-2011, 12:37 AM
It sounds as if your fans are working correctly. The fans only come on when the coolant temperature rises, and even then only one fan turns on. If the temperature continues to rise, both fans turn on. Turning on the AC will cause both fans to run.

Are you sure it's overheating?

thephantom1492
07-08-2011, 01:45 AM
You seems to have a failed fan.

Both fan should be on at once.
There is 2 modes for the fans:
low speed: it put both in series, in this mode if one is faulty the other do not run.
High speed: both fan turn on.

AC put the fans in high speed mode.

You said one fan have taped wiring? if there was no connector there it mean the fan was already replaced or someone removed the connector or someone cut and taped the wires. There is no manufacturer that just twist the wires and tape, this make an unreliable connection that can cause issues, so they don't want that.

To test the fan, just put the 2 wires going to the fan on 12V, it should spin. if not the fan motor is dead and need replacement.

As to how to test relay...
Relay is an electrically controlled switch.
The relay is in 2 parts: coil and switch.
Dending on the relay, it usually have 4 or 5 pins, 5 being more common.
2 pins is the coil, an electro magnet that pull the spring loaded switch inside. Send 12V to it and it will activate the switch.

For 4 pins relay, it mean there is 2 pins for the switch part. most are shorted when the coil is energised, as in sending 12V to the coil pull the switch to "on". for completeness, there is some relay that is inversed: power to turn off, but you won't find them on car.
To test: use a multimeter on continuity or resistance test. check the switch side, shouln't conduct (high resistance).
Power the coil, retest the switch, it should conduct (low resistance).

For 5 pins relay, the switch part is actually the 2 kind previously mentioned. You have a common pin and 2 "output" pin. when not powered the switch is shorted to one of the output. when powered it short the other instead. think of "this or that" kind of switch.
To test: put one probe on the common, find the one that conduct, the other pin shouln't conduct. power the coil. The results should be inversed.

See http://www.reuk.co.uk/OtherImages/5-pin-12V-automotive-relay.jpg for reference.
Note that the pin number might be different.
On this one, 85-86 is the coil. it is non-polarised, meaning that it's not important which side is + and which is -.
Common is 30.
87A will be non-present on 4 pins one
87 is the powered on output.

As you can see, the coil attract the switch, and switch from 87A to 87...

xeroinfinity
07-15-2011, 07:32 PM
Welcome to AF jerryhunt92284.

1 fan runs when AC is on or temp reach higher than 230 deg, at around 240-50 both should kick on. Both fans will also run if ac pressure is high.

For the 99 # 8 is cooling fan fuse(large) #12,14,15 all are micro relays for the cooling fans.
#55 & 54 are not used.

here is the procedure to test your coolant temp sensor (http://www.automotiveforums.com/vbulletin/showthread.php?t=660655).


Hope that helps

jerryhunt92284
07-16-2011, 11:05 PM
Well, I'm not to good with the electric side (as if I have a good side...). I did replace the fan motor, and to my dismay, it still does not work. The old lady just had to go everywhere today and the red light came on and stayed on with the temp over 250 for the 10ish minute trip home. I'm sure something got hurt there...

But I did change the fan out and it still won't come on. Like I said before, I've replaced the reservoir (it was cracked), the coolant sensor (troubleshooting), the large radiator hose (cracked right after the coolant sensor was changed out), and now the fan motor. We previously checked the relays (just by swapping them out), the fuses, and the neighbor checked the wires going to the fan (with a light pen?) and he said it was getting power.

:banghead: What now? I'm still foggy on the instructions of applying 12V directly to the fan. But I will try that tomorrow. Thanks everyone for the help.

Oh, and after today's events. It only seems to take the car about 10 minutes to go from zero ambient temperature (in the desert and the car is black, so... about 100degrees) to 225 or more. I've waited until the red light went on for the temperature before giving up on the new fan motor to come on. The passenger/AC fan works just fine.

danielsatur
07-17-2011, 10:22 AM
Disconnect ECT sensor wire. The coolant system should go into default mode, and both fans should turn on.

jerryhunt92284
07-17-2011, 01:35 PM
i did end up applying power to the fan and the fan did come on. but the fan won't work directly. I did try disconnecting the etc sensor and that did not work either. i tried wiring them directly to each other but all that did was blow a fuse.:runaround::banghead:

thephantom1492
07-17-2011, 06:58 PM
the 2 fans together sure will blow the fuse that is 1 fan sized.

If you are sure that the relay is fine (have you triple checked it?)... you might want to do some tests.

The relay should be powered on when the fan should be on. With a test light check to see if the relay get power.

There is 6 reasons to why the fan don't turn on:
* blew 12V fuse
* blew ground fuse (not all model have this one)
* failed relay
* fault in wire from ECU to relay
* fault in wire from relay to fan
* faulty ECU

There is some weirder reasons too, but, well, it always depend on how bored the engineer was that morning when he conceived the car :D (like... why a ground fuse?)

jerryhunt92284
07-19-2011, 01:37 AM
well, i ended up saying the hell with it and installing a switch to just turn on when the engine gets hot.

Prior to that...the other day we had a problem where it got hot and usually as long as we get moving, the air flow will cool down the engine to a manageable temperature. It didn't do so and it was about a 10 minute ride home. It was past the 270 mark and the red light on all the way home. The air flow didn't help.

So, now it will overheat within about 15 minutes of driving. After about 5 minutes of the engine running, the temperature needle will rise like a second hand (yet smoother). I've heard that I should check the thermostat and see if that is it, but honestly...i think I warped a head or cracked the block. There is no water mixed with the oil just yet and no black smoke, so I'm not sure. Hesitant to take it in to the shop just so I can dump more money into what seems to be a time bomb.

Thoughts?

thephantom1492
07-19-2011, 02:33 AM
might want to see if you have air in the coolant lines.
If you cracked the head, the first thing that you will get is bubble in the radiator.

skeeter123
07-19-2011, 08:50 AM
Does your switch turn them on High or Low speed?

It sounds like the problem is in the ground/return line for CoolFan #1 (driver's side) This ground line comes from the Fan mode-control relay and goes to a ground-splice-pack. You may want to verify that the mode-control relay really works, and ohm-out the wire from the relay, to the ground-splice-pack, to ground. If that ground-line for CoolFan #1 is bad, it will run in Low speed ("grounded" thru other fan, which also runs at low speed), but won't run at high speed when ground is routed to the splice pack).

Check out Xero's wiring diagram at:

http://i28.photobucket.com/albums/c242/xeroinfinity/SeCond%20Hand/heater-acwiringdiag.jpg

Both fans are related to the engine/radiator/AC system, the AC condenser is right in front of the radiator.

The fans are either both off, both on (low speed), or both on (high speed). Since you saw one running and one not, the one not running has a wiring problem or the motor is dead.
Hope this helps.

xeroinfinity
07-21-2011, 02:43 PM
i would replace the thermostat, and pray the head gaskets or intake hasnt blown.
And if the thermo replacement doesnt fix the over heating probly time to rerplace some gaskets. :eek7:

Btw did you buy new relays for the fans?

inafogg
07-21-2011, 04:08 PM
i would think especially if this all started after resivior was replaced is that you have air in the system.these cars can be a problem bleeding.try letting it idle
with the cap off.coolant will rise/fall in radiator as air bubbles are released.

xeroinfinity
07-23-2011, 04:16 PM
i would think especially if this all started after resivior was replaced is that you have air in the system.these cars can be a problem bleeding.try letting it idle
with the cap off.coolant will rise/fall in radiator as air bubbles are released.

i agree, if you did not get all the air out of the cooling system it will get temp spikes and heat up realy fast.
But if the air is all out you could have other issues like head or intake gaskets needing replaced.

here is something i wanted to post earlier on this fan set up but couldnt find.(thanks BNaylor)
The fan system includes the following components:

* Two (2) electric cooling fans (Left & Right)
* Three (3) fan relays (COOL FAN 1, COOL FAN & COOL FAN 2)
* Two (2) fuses (30 Amp Maxi fuses #6 [COOL FAN 1] & #1 [COOL FAN 2])
* All associated wiring & connectors

There are three basic modes for the fans: OFF, Low-Speed, and High-Speed. These modes are controlled by the Powertrain Control Module (PCM).

Fans OFF:

* When the coolant temperature is less than about 220°F (104°C) or
* The A/C refrigerant pressure is less than 190 psi (A/C off).

Low-Speed:

* When the coolant temperature is between about 220°F (104°C) and 230°F (110°C) or
* The A/C refrigerant pressure is more than 190 psi (1310 kPa) or
* When car is turned off and the coolant temp is more than about 284°F (140°C) and system voltage is more than 12 Volts. Fans will run for about 3 minutes.

High-Speed:

* When the coolant temperature is above about 230°F (110°C) or
* The A/C refrigerant pressure is more than 240 psi (1655 kPa) or
* When certain DTCs are set.

Other information:

* The thermostat for these cars normally opens at about 195°F (93°C)
* The "Engine Coolant Temperature" message should appear (on dash) if the engine coolant temperature is above about 262°F (128°C). PCM sends a message to the Instrument Panel indicating temperature.
* The "Engine Coolant Level" indicator should appear (on dash) if the coolant level goes below a certain level.

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